[Federal Register Volume 59, Number 145 (Friday, July 29, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-17650]


[[Page Unknown]]

[Federal Register: July 29, 1994]


_______________________________________________________________________

Part III





Environmental Protection Agency





_______________________________________________________________________



40 CFR Parts 141 and 142




National Primary Drinking Water Regulations: Enhanced Surface Water 
Treatment Requirements; Proposed Rule
ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 141 and 142

[WH-FRL-4998-1]

 
National Primary Drinking Water Regulations: Enhanced Surface 
Water Treatment Requirements

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: EPA is proposing to amend the Surface Water Treatment Rule to 
provide additional protection against disease-causing organisms 
(pathogens) in drinking water. This action would primarily focus on 
treatment requirements for the waterborne pathogens Giardia, 
Cryptosporidium, and viruses. With the exception of one requirement 
(sanitary surveys), this action would apply to all public water systems 
that use surface water or ground water under the influence of surface 
water, and serve 10,000 people or more. Among the features of the rule 
would be a stricter watershed control requirement for systems using 
surface water that wish to avoid filtration; a change in the definition 
of ground water under the influence of surface water to include the 
presence of Cryptosporidium; a periodic sanitary survey requirement for 
all systems using surface water or ground water under the influence of 
surface water, including those that serve fewer than 10,000 people; a 
health goal (maximum contaminant level goal) of zero for 
Cryptosporidium; and several alternative requirements for augmenting 
treatment control of Giardia, Cryptosporidium, and viruses.

DATES: Comments should be postmarked or delivered by hand on or before 
May 30, 1996. Comments received after this date may not be considered. 
Public hearings will be held at the addresses indicated below under 
ADDRESSES on August 30, 1996 (and 31, if necessary) in Denver, CO and 
on September 13, 1994 (and 14, if necessary) in Washington, DC.

ADDRESSES: Send written comments to ESWTR Docket Clerk, Water Docket 
(MC-4101); U.S. Environmental Protection Agency; 401 M Street, SW; 
Washington, DC 20460. Please submit any references cited in your 
comments. EPA would appreciate an original and three copies of your 
comments and enclosures (including references). Commenters who want EPA 
to acknowledge receipt of their comments should include a self-
addressed, stamped envelope. No facsimiles (faxes) will be accepted 
because EPA cannot ensure that they will be submitted to the Water 
Docket. The Agency requests commenters to follow the instructions 
regarding format provided in Section IX of the Preamble, immediately 
before the list of references.
    The Agency will hold public hearings on the proposal at two 
different locations indicated below:

1. Denver Federal Center, 6th and Kipling Streets, Building 25, Lecture 
Halls A and B (3d Street), Denver, CO 80225 on August 30 (and 31, if 
necessary), 1994.
2. EPA Education Center Auditorium, 401 M Street SW., Washington, D.C. 
20460, on September 13 (and 14, if necessary), 1994.

    The hearings will begin at 1:00 p.m., with registration at 12:30 
p.m., on the first day. The hearings will begin at 9:30 a.m., with 
registration at 9:00 a.m., on the second day. The Hearings will end at 
4:00 p.m., unless concluded earlier. Anyone planning to attend the 
public hearings (especially those who plan to make statements) may 
register in advance by writing the ESWTR Public Hearing Officer, Office 
of Ground Water and Drinking Water (4603), USEPA, 401 M Street, S.W., 
Washington, D.C. 20460; or by calling Tina Mazzocchetti, (703) 931-
4600. Oral and written comments may be submitted at the public hearing. 
Persons who wish to make oral presentations are encouraged to have 
written copies (preferably three) of their complete comments for 
inclusion in the official record.
    The proposed rule with supporting documents and all comments 
received are available for review at the Water Docket at the address 
above. For access to Docket materials, call (202) 260-3027 between 9 am 
and 3:30 pm for an appointment.

FOR FURTHER INFORMATION CONTACT: The Safe Drinking Water Hotline, 
Telephone (800) 426-4791. The Safe Drinking Water Hotline is open 
Monday through Friday, excluding Federal holidays, from 9 a.m. to 5:30 
p.m. Eastern Time. For technical inquiries, contact Stig Regli or Paul 
S. Berger, Ph.D., Office of Ground Water and Drinking Water (MC 4603), 
U.S. Environmental Protection Agency, 401 M Street SW., Washington DC 
20460; telephone (202) 260-7379 (Regli) or (202) 260-3039 (Berger); or 
Bruce A. Macler, Ph.D., Water Management Division, Region 9, U.S. 
Environmental Protection Agency, 75 Hawthorne Street (W-6-1), San 
Francisco, CA 94105-3901; telephone (415) 744-1884.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Statutory Authority
II. Regulatory Background
III. Discussion of Proposed Rule
    A. Basis for Amending Existing SWTR: Limitations of SWTR
    B. General Approach for Revising SWTR
    C. Proposed Maximum Contaminant Level Goal and Treatment 
Technique for Cryptosporidium
    D. Proposed Revisions to SWTR under All Treatment Alternatives
    1. Inclusion of Cryptosporidium in definition of ``groundwater 
under the direct influence of surface water''
    2. Inclusion of Cryptosporidium in watershed control 
requirements
    3. Sanitary surveys for all surface water systems
    4. Possible supplemental requirements
    E. Alternative Treatment Requirements
    1. Options for defining pathogen densities in source waters
    2. Treatment alternatives for controlling pathogens
IV. State Implementation
    A. Special State Primacy Requirements
    B. State Recordkeeping Requirements
    C. State Reporting Requirements
V. Public Notification Language
VI. Economic Analysis
    A. Cost of Proposed Rule
    B. Benefits of Proposed Rule
VII. Other Statutory Requirements
    A. Executive Order 12866
    B. Regulatory Flexibility Act
    C. Paperwork Reduction Act
    D. Science Advisory Board, National Drinking Water Advisory 
Council, and Secretary of Health and Human Services
    E. Consultation with State, Local, and Tribal Governments
VIII. Request for Public Comment
IX. Instructions to Commenters
X. References

I. Statutory Authority

    The Safe Drinking Water Act (SDWA or the Act), as amended in 1986, 
requires EPA to publish a ``maximum contaminant level goal'' (MCLG) for 
each contaminant which, in the judgment of the EPA Administrator, ``may 
have any adverse effect on the health of persons and which are known or 
anticipated to occur in public water systems'' (Section 1412(b)(3)(A)). 
MCLGs are to be set at a level at which ``no known or anticipated 
adverse effects on the health of persons occur and which allows an 
adequate margin of safety'' (Section 1412(b)(4)).
    At the same time EPA publishes an MCLG, which is a non-enforceable 
health goal, it also must publish a National Primary Drinking Water 
Regulation (NPDWR) that specifies either a maximum contaminant level 
(MCL) or treatment technique (Section 1401(1), 1412(a)(3), and 
1412(b)(7)(A)). A treatment technique may be set in lieu of an MCL if 
it is not ``economically or technologically feasible'' to determine the 
level of a contaminant.
    Section 1412(b)(3) of the Act requires EPA to publish regulations 
for at least 25 contaminants at three year intervals. Section 
1412(b)(9) requires EPA to review each NPDWR every three years and 
revise it if appropriate.
    Section 1412(b)(7)(C) requires the EPA Administrator to publish a 
NPDWR ``specifying criteria under which filtration (including 
coagulation and sedimentation, as appropriate) is required as a 
treatment technique for public water systems supplied by surface water 
sources''. In establishing these criteria, EPA is required to consider 
``the quality of source waters, protection afforded by watershed 
management, treatment practices (such as disinfection and length of 
water storage) and other factors relevant to protection of health''. 
This section of the Act also requires EPA to promulgate a NPDWR 
requiring disinfection as a treatment technique for all public water 
systems and a rule specifying criteria by which variances to this 
requirement may be granted.
    Section 1445(a)(1) of the Act requires a public water system to 
``establish and maintain such records, make such reports, conduct such 
monitoring, and provide such information as the Administrator may 
reasonably require by regulation . . .''.
    Section 1414(c) requires each owner or operator of a public water 
system to give notice to persons served by it of any failure to comply 
with an MCL, treatment technique, or testing procedure required by a 
NPDWR and any failure to comply with any monitoring required pursuant 
to section 1445 of the Act.

II. Regulatory Background

    Two NPDWRs control disease-causing microorganisms (pathogens) in 
public water supplies--the Total Coliform Rule (TCR)(54 FR 27544; June 
29, 1989) and the Surface Water Treatment Rule (SWTR)(54 FR 27486; June 
29, 1989). A third regulation, the Groundwater Disinfection Rule 
(GWDR), which is currently under development, will add further 
protection for systems using ground water.
    The SWTR met the requirements of Section 1412(b)(7)(C) and, for 
surface waters, Section 1412(b)(8) of the SDWA, as amended in 1986. The 
SWTR requires all systems using surface water, or ground water under 
the direct influence of surface water, to disinfect. In addition, all 
such systems are required to filter their water unless they demonstrate 
that they have an effective watershed protection program and meet other 
EPA-specified requirements (Sec. 141.71). The watershed control program 
must minimize the potential for source water contamination by Giardia 
cysts and viruses, and typically includes characterization of watershed 
hydrology, land ownership by the system, and activities on the 
watershed that might have an adverse effect on source water quality. 
The rule also requires an annual on-site inspection of all systems that 
wish to avoid filtration. This inspection must demonstrate that the 
required watershed control program and disinfection treatment processes 
are adequately designed and maintained. The SWTR also established MCLGs 
of zero for Giardia lamblia, viruses and Legionella.
    The SWTR requires all systems to achieve at least 99.9% (3-log) 
removal/inactivation of Giardia lamblia cysts, and 99.99% (4-log) 
removal/inactivation of enteric viruses. The intention of these 
provisions was to provide appropriate multiple barriers of treatment to 
control pathogen occurrence in finished drinking water. This rule was 
promulgated as a treatment technique rather than an MCL, because EPA 
believed that routine monitoring for the pathogens was not economically 
or technologically feasible. Another pathogen, Cryptosporidium, was 
considered for regulation under the SWTR, but was not addressed, 
because EPA lacked sufficient health, occurrence, and water treatment 
control data regarding this organism at that time.
    The TCR established MCLGs of zero for total coliforms, which 
includes fecal coliforms and E. coli. MCLs, monitoring requirements, 
and analytical requirements were promulgated for these organisms. The 
TCR requires all public water systems that collect fewer than five 
samples per month to have an on-site sanitary survey every five years 
(ten years for some systems). The purpose of this requirement is to 
help ensure the long-term quality and safety of drinking water in small 
systems that cannot be accomplished by infrequent coliform monitoring.
    The TCR and SWTR were promulgated to minimize both epidemic and 
endemic waterborne microbial illness. The public health goal, as 
described in the preamble to the SWTR, was to provide treatment to 
ensure an acceptable risk of less than one waterborne microbial illness 
per year per 10,000 people.
    In addition to the SWTR, TCR, and GWDR, EPA is also developing a 
rule that would limit concentration levels of disinfectants and the 
chemical disinfection byproducts (DBPs) resulting from their use. The 
use of chemical disinfectants in water treatment results in a 
substantial decrease in waterborne microbial illness and is an integral 
part of a multiple-barrier removal/inactivation approach. However, 
disinfectants and DBPs may present potential health risks themselves. 
DBPs form when disinfectants used for microbial control in drinking 
water react with various organic chemicals in the source water. Some of 
these are known to be toxic to humans or are considered to be probable 
human carcinogens. As such, a number of disinfectants and DBPs were 
included on the 1991 Drinking Water Priority List (56 FR 1470, January 
14, 1991) as candidates for future regulations. To address these health 
issues, EPA is proposing elsewhere in today's Federal Register the 
disinfectants/disinfection byproducts (D/DBP) rule, which includes 
NPDWRs for several disinfectants and disinfectant byproducts.
    To develop the D/DBP Rule, EPA instituted a formal regulation 
negotiation process in 1992 with potentially affected parties (57 FR 
53866; Nov. 13, 1992). The committee established to negotiate the 
regulation included representatives from water utilities, State and 
local health and regulatory agencies, environmental groups, consumer 
groups, and EPA (hereafter the Negotiating Committee or the Committee). 
One of the major goals addressed by the Committee was to develop an 
approach that would reduce the level of exposure from disinfectants and 
DBPs without undermining the control of pathogens. The intention was to 
ensure that drinking water is microbiologically safe at the limits set 
for disinfectants and DBPs and that these chemicals do not pose an 
unacceptable risk at these limits. The approach in developing this rule 
considered the constraints of simultaneously treating water for these 
different concerns. As part of this effort, the Negotiating Committee 
decided that the SWTR may need to be revised to address health risk 
from high densities of pathogens in poor quality source waters and from 
the protozoan, Cryptosporidium. If such requirements were deemed 
necessary, and could be promulgated concurrently with new D/DBP 
regulations (the regulations proposed elsewhere in today's Federal 
Register and termed ``Stage 1 D/DBPR''), a system could comply with 
both regulations and meet the intended public health goals.
    The Negotiating Committee also decided that to develop a reasonable 
set of rules, including today's proposed rule, and to understand more 
fully the limitations of the current SWTR, additional field data were 
critical. Thus, the Committee agreed to the development of an 
information collection rule (ICR) that would require, in part, systems 
serving a population of 10,000 or greater to determine the density of 
specific pathogens in their source water and to characterize their 
treatment processes. Under the ICR, systems serving populations greater 
than 100,000 would also be required to monitor for pathogens in their 
finished water (depending upon the pathogen density in the source 
water), and the concentration of DBPs and parameters related to their 
formation at various steps in the treatment process. To this end, EPA 
proposed the ICR on February 10, 1994 (59 FR 6332) that would require 
this additional information. The Committee agreed to the requirements 
in the proposed ICR as necessary and reasonable.
    According to the regulatory strategy developed by the Committee, 
systems serving a population of 10,000 or greater would use the 
monitoring and treatment data collected under the ICR to decide what 
additional treatment measures, if any, would be necessary to protect 
the public from pathogens while controlling for DBPs. This decision 
would be based on criteria specified either in amendments to the SWTR 
or by guidance. Today's proposed rule includes a variety of regulatory 
options, from requiring systems to provide minimum levels of treatment 
based upon the density of pathogens in the source water to maintaining 
the existing requirements of the SWTR.
    According to the Committee's strategy, amendments to the SWTR would 
be developed under two rules. The first of these rules, which is 
today's proposed rule, would be an interim enhanced SWTR (ESWTR) that 
would only pertain to systems serving 10,000 people or greater. Data 
collected under the ICR would be used to determine the appropriate 
regulatory option(s) under this rule, and then to implement it at the 
time systems are required to comply with the Stage 1 D/DBP regulations. 
Following the full compilation and analysis of all data collected under 
the ICR rule and from other research findings, EPA would propose a 
long-term ESWTR with which systems serving fewer than 10,000 people 
would comply while also complying with the Stage 1 D/DBP rule. The 
long-term ESWTR might also include additional refinements for systems 
serving 10,000 people or greater. Today's proposal also satisfies the 
provision in section 1412(b)(9) of the SDWA for review of NPDWRs every 
three years; the SWTR was promulgated on June 29, 1989, and became 
effective in stages, beginning December 31, 1990.

III. Discussion of Proposed Rule

A. Basis for Amending Existing SWTR: Limitations of SWTR

    As discussed above, the SWTR requires all systems using surface 
water, or ground water under the direct influence of surface water, to 
disinfect. It also requires all such systems to filter their water 
unless they can demonstrate that they have an effective watershed 
control program, meet source water quality criteria, achieve minimum 
disinfection requirements, and have no evidence of reported waterborne 
disease among the served population. The SWTR also specifies that 
systems using surface water must treat water to remove/inactivate at 
least 99.9% of the Giardia lamblia cysts and at least 99.99% of the 
enteric viruses, regardless of their densities in the source waters. 
The SWTR does not require a system to monitor its source water or 
drinking water for these pathogens. At the time of promulgation, EPA 
recognized a variety of uncertainties and unknowns regarding potential 
health risks, but these were not possible to address at that time. 
Subsequently, additional information has become available that 
indicated possible deficiencies in the SWTR. Some of these deficiencies 
are described below.
SWTR Did Not Address Cryptosporidium
    During the development of the SWTR, the United States experienced 
its first recognized waterborne disease outbreak of cryptosporidiosis, 
caused by the protozoan, Cryptosporidium (D'Antonio et al., 1985). 
Other outbreaks caused by this pathogen have since been reported both 
in the United States and other countries (Smith et al., 1988; Hayes et 
al., 1989; Levine and Craun, 1990; Moore et al., 1993; Craun, 1993). 
Because of the lack of data before 1989 on Cryptosporidium oocyst 
occurrence and removal by treatment, EPA decided to regulate this 
pathogen in a future rulemaking, rather than to delay publication of 
the SWTR until this data was available. Thus, the SWTR does not now 
specifically address Cryptosporidium treatment removal/inactivation 
requirements, watershed control requirements for Cryptosporidium for 
systems that wish to avoid filtration, or a definition of ground water 
under the influence of surface water that includes Cryptosporidium. 
Moreover, the assumptions about Giardia reduction under the SWTR may 
not be applicable to Cryptosporidium, which, based on laboratory 
studies, is much more resistant to common disinfection practices than 
is Giardia (Korich et al., 1990; Korich et al., 1992). Since 
publication of the SWTR in 1989, some information on Cryptosporidium 
occurrence and control measures has been published. EPA will have new 
data available shortly from systems that monitor for this organism 
under the ICR and from research currently being carried out by the 
Agency and the water industry. As a result, EPA believes that it will 
soon be in a better position to develop a suitable regulation for 
Cryptosporidium.
Specified Pathogen Reductions May Be Inadequate
    The 3-log removal/inactivation of Giardia and 4-log removal/
inactivation of enteric viruses required by the SWTR were developed to 
provide adequate protection from pathogens in average quality source 
water, and thus may be inadequate when a system is supplied by poorer 
quality source water with high levels of these or other pathogens. In 
developing the SWTR, EPA assumed, on the basis of data available at 
that time, that this level of treatment was adequate for the vast 
majority of systems.
    Additionally, risk assessments for the pathogens of concern had 
high degrees of uncertainty, such that the risks associated with a 
given level of pathogen contamination were unclear. Moreover, methods 
for quantifying these organisms were not generally available. 
Therefore, the Agency believed that a simple, yet conservative 
treatment requirement was most appropriate. However, it was apparent 
during the development of the SWTR that the level of treatment being 
specified might not always be adequate. Therefore, the Agency published 
associated guidance recommending greater treatment for systems supplied 
by poorer quality source waters (EPA, 1991a).
    Subsequent data on Giardia and virus densities in source water and 
drinking water, however, bring into question the assumption that the 
treatment specified in the SWTR was adequate for most systems. These 
new data suggest that the concentrations of Giardia cysts and viruses 
in the source waters of many systems may be too great for the specified 
level of treatment to adequately control waterborne pathogens. For 
example, LeChevallier et al. (1991a,b) examined Giardia and 
Cryptosporidium levels in the source waters and filtered drinking 
waters of 66 surface water systems in 14 States and one Canadian 
province. They detected at least one of these two organisms in 97% of 
the raw water samples. Giardia densities ranged from 0.04 to 66 cysts/L 
(geometric mean of 2.77 cysts/L), while Cryptosporidium densities 
ranged from 0.07 to 484 oocysts/L (geometric mean of 2.70 oocysts/L).
    These investigators also detected at least one of the two organisms 
in the drinking water of 39% of the systems. For those drinking waters 
that were positive, Giardia densities ranged from 0.29-64 cysts/100L 
(geometric mean 4.45 cysts/100L), while Cryptosporidium densities 
ranged from 0.13 to 48 oocysts/100L (geometric mean 1.52 oocysts/100L). 
According to the investigators, 78% of the systems that were positive 
for Giardia or Cryptosporidium met the turbidity standards specified by 
the SWTR. Based on a risk assessment model developed for Giardia, 24% 
of the 66 systems might not meet the health goal in the SWTR of no more 
than the one Giardia infection annually per 10,000 people per year 
(LeChavallier et al., 1991b). (This incidence of infection is a 
conservative estimate of illness, since not all infected people become 
ill.) This study suggests that the SWTR may need to be revised if an 
annual 10-4 risk level, or some other desired risk level, is to be 
achieved by all systems in the United States.
    EPA used the data in LeChevallier et al. (1991a,b) to calculate the 
percentage of systems that use source waters containing various 
densities of Giardia cysts. The Agency calculated that about 85% of the 
source waters in the study contained 10 cysts/100L or more, while about 
45% contained 100 cysts/100L or more. Many of these systems currently 
provide four, five, or even six or more logs of removal/inactivation 
and therefore are able to achieve EPA's 10-4 annual risk goal. 
However, if such systems were to reduce existing levels of disinfection 
to more easily meet new D/DBP regulations, and only marginally meet the 
three-log removal/inactivation requirement for Giardia specified in the 
current SWTR, they could experience significant increases in microbial 
risk (Regli et al., 1993; Grubbs et al., 1992; EPA, 1994)).
    An epidemiology study by Payment et al. (1991) also suggests that 
the pathogen density reductions specified by the SWTR may not be 
sufficient for adequate protection. The goal of this study was to 
determine the extent to which drinking water caused gastrointestinal 
disease in a community served by poor quality source water that was 
subjected to full conventional treatment. In this study, the 
investigators carried out a trial where 299 households in a community 
drank water from a reverse-osmosis water filter, while 307 households 
used the usual tapwater. According to the data, 35% of the reported 
gastrointestinal illness was associated with the drinking water. The 
etiologic agent(s) were not identified, but a plausible explanation is 
that pathogens were in the finished water. A recent analysis by Haas et 
al. (1993) also suggests that high levels of microbial risk far above 
the health goal of the existing SWTR may be occurring in systems with 
highly contaminated source waters that may only minimally comply with 
the SWTR.
    Several other recent studies have shown that Giardia and 
Cryptosporidium cysts/oocysts can be found in filtered drinking waters 
in systems served by highly contaminated source waters (Clancy, 1993; 
EPA, 1993). If treatment is inadequate in reducing pathogens to an 
acceptable level, EPA must consider revising and strengthening 
treatment requirements. A mitigating factor is that, based upon a 
microscopic examination of the cysts/oocysts detected by LeChevallier 
et al. (1991b), most of the cysts/oocysts in the drinking water may not 
be viable. This observation, however, has not yet been confirmed.
Virus CT Values May Be Greater Than Assumed by SWTR
    The SWTR assumes that disinfection more readily controls viruses 
than may actually be the case. The Guidance Manual to the SWTR (EPA, 
1991a) identifies the disinfection CT values (disinfectant 
concentration times the contact time) for viruses. These data are based 
on laboratory studies in which a dispersed suspension (i.e., non-cell 
associated, non-aggregated) of hepatitis A virus was used. These CT 
values relative to the much higher CT values needed for Giardia 
inactivation for systems to comply with the SWTR have led to the 
assumption by some that systems which satisfactorily control for 
Giardia cysts will adequately control for pathogenic viruses. (The CT 
values to comply with the level of disinfection inactivation 
requirements for viruses in the Guidance Manual to the SWTR are one to 
two orders of magnitude below the CT values necessary to achieve the 
inactivation requirements for Giardia.)
    However this assumption may not always be valid. In environmental 
waters, viruses are usually aggregated or associated with cell debris, 
some of which may not be removed entirely by filtration processes. Such 
cell-associated aggregates are considerably more resistant to 
disinfection than free viruses (Williams, 1985; Sobsey, 1991). 
Moreover, some pathogenic enteric viruses may be substantially more 
resistant to disinfection than hepatitis A (Keswick et al., 1985). In 
addition, laboratory studies to determine CT values for viruses, even 
with applied uncertainty factors, may underestimate the actual CT 
values necessary to achieve the desired level of inactivation, since 
viruses in the environment may be hardier and less susceptible to 
disinfection.
    The detection of viruses in fully treated waters (i.e., after 
coagulation, sedimentation, filtration, and disinfection) (Gerba and 
Rose, 1990; Payment, 1985; Hurst, 1991) also suggests that viruses in 
environmental sources have greater CT values than those published in 
the Guidance Manual. Hurst (1991), for example, summarized the 
published data on viruses in drinking water, and found that the 
percentage of samples positive for viruses ranged from 0 to 100%. In 
one study, Payment et al. (1985) detected enteroviruses in 7% of 
finished water samples (1,000 L samples from 7 systems), with an 
average density of 0.0006 most probable number of cytopathogenic units. 
In another study, Payment (1981) detected 1-10 enteroviruses/100L in 
most drinking water samples in a system using poor quality source 
water.
    The above data also suggests that EPA needs to reassess the 4-log 
level of treatment required for viruses under the SWTR. Under this 
requirement, a system may only provide a 2-log inactivation of viruses 
by disinfection and still meet the 4-log overall treatment requirement 
(under current EPA guidance, systems using conventional treatment are 
assumed to achieve a 2- log removal of viruses by clarification 
processes alone). For some systems, virus densities in surface waters 
may be sufficiently high to warrant at least a 4-log or greater level 
of inactivation by disinfection alone (and a 6-log or greater removal 
of viruses with clarification and disinfection) to achieve desired risk 
levels (Regli et al., 1991). The Agency would like to determine what 
minimum level of disinfection inactivation is necessary for surface 
water supplies to ensure adequate virus control, regardless of Giardia 
densities. EPA intends to use data from the ICR to: (1) Help clarify 
the adequacy of using Giardia as a target organism to control for 
viruses in systems with different source water qualities, (2) determine 
what assumptions can be made regarding quantification of virus removal 
for different treatment processes and disinfection conditions, and (3) 
determine what, if any, changes to the SWTR are needed to control 
pathogenic viruses.
DBP Rule May Undermine Pathogen Control
    Some systems currently exceed the required Giardia and virus 
reductions specified by the SWTR. The DBP Rule may potentially 
undermine pathogen control in these systems by prompting them to reduce 
DBP concentrations at the expense of pathogen control (e.g., by 
shifting point of disinfection to later in the treatment chain, 
reducing disinfection dose, or switching to a weaker disinfectant such 
as chloramines). These systems would still have to comply with the 
removal/inactivation criteria in the current SWTR, but would do so with 
a lower margin of safety. This situation might result in a substantial 
increase in waterborne illness for systems using a poor quality source 
water. For example, according to a model developed by EPA (Regli et 
al., 1993), a reduction of the MCL for total trihalomethanes (TTHMs) 
(one of the toxic byproducts) from 100g/L to 75g/L 
could increase the incidence of waterborne giardiasis in some systems 
by as many as 10,000 per million people per year, if the existing SWTR 
is not amended to require higher levels of treatment for poor quality 
source waters.
    This situation is further evidence that EPA may need to revise the 
SWTR to ensure that measures taken by systems to comply with the 
forthcoming DBP Rule do not increase the health risk from pathogens.

B. General Approach for Revising SWTR

    Under the negotiated rulemaking, the Negotiating Committee agreed 
to propose three rules: (1) ICR, proposed on February 10, 1994 (59 FR 
6332), (2) D/DBP regulations (proposed in today's Federal Register), 
and (3) ESWTR. EPA is planning to remedy the shortcomings of the SWTR 
indicated above through two sequential stages--an interim ESWTR and a 
long-term ESWTR. Today's rule proposes the interim ESWTR. The Agency 
and the Negotiating Committee decided that this phased approach was 
appropriate because of the uncertainties associated with lack of data. 
EPA needs much more data on the concentrations of Giardia, 
Cryptosporidium, and enteric viruses for various qualities of source 
waters, with variations over time and season, to determine the need for 
additional treatment. Some members of the Negotiating Committee 
believed that health effects information, especially dose response data 
for pathogens of concern, is also important to ensure that EPA selects 
the most appropriate control option. In addition, EPA needs more field 
data on the effectiveness of different types of water treatment for 
controlling these pathogens. Data from the ICR and various research 
studies would provide much of this information, sufficient in EPA's 
view to refine the present proposed interim rule. Additional work would 
culminate in a long-term ESWTR that would be protective for all surface 
water system sizes (including those that serve fewer than 10,000 
people) and would also include possible refinements to any interim 
requirements for larger systems. EPA believes that the interim and 
long-term ESWTR rules are essential for providing adequate human health 
protection; however, some members of the Negotiating Committee believed 
that the most appropriate regulatory criteria to provide this 
protection are not yet apparent.
Schedule of Regulations
    Table I-1 indicates the schedule agreed to by the Negotiating 
Committee for proposing, promulgating, and implementing these rules. 
Implementation dates for the ICR are indicated under the columns of the 
Stage 2 D/DBP rule and ESWTR to reflect the relationship between these 
rules. Although the schedule for proposing these rules has slipped 
slightly, EPA believes the scheduled promulgation dates for the ESWTR 
and D/DBP Rule can still be met.
    The Negotiating Committee believes that the December 1996 scheduled 
date for promulgating the Stage 1 D/DBP Rule reflects the shortest time 
possible by which the interim ESWTR, if necessary, could also be 
promulgated. EPA is proposing that the Stage 1 D/DBP regulations and 
the interim ESWTR become effective on the same date of June 30, 1998, 
for those surface water systems, or ground water systems under the 
direct influence of surface water, serving 10,000 people or more. This 
strategy is necessary so that systems do not degrade pathogen control 
in attempting to comply with the Stage 1 D/DBP regulations.

    Table I-1.--Proposed D/DBP, ESWTR, ICR Rule Development Schedule    
------------------------------------------------------------------------
  Time                                                                  
 line      State 1 DBP rule      Stage 2 DBP rule           ESWTR       
------------------------------------------------------------------------
                                                                        
12/93..  ....................  Propose information   Propose information
                                collection            collection        
                                requirements for      requirements for  
                                systems>100k.         systems >10k.     
3/94...  Propose required      Propose Stage 2.      Propose interim    
          enhanced              MCLs for TTHMs (40    ESWTR for         
          coagulation for       g/l), HAA5   systems>10k.      
          systems with          (30 g/l),                      
          conventional          BAT is precursor                        
          treatment. MCLs-      removal with                            
          TTHMs (80g/  chlorination.                           
          l), HAA5 (60ug/l),                                            
          bromate, chlorite.                                            
          Disinfectant limits.                                          
6/94...  ....................  Promulgate ICR......  Promulgate ICR.    
8/94...  Close of public       ....................  Public comment     
          comment period.                             period for        
                                                      proposed ESWTR    
                                                      closes.           
10/94..  ....................  Systems>100k begin    Systems>100k begin 
                                ICR monitoring.       ICR monitoring.   
1/95...  ....................  ....................  Systems 10-100k    
                                                      begin source water
                                                      monitoring.       
10/95..  ....................  SW systems>100k, GW                      
                                systems>50k begin                       
                                bench/pilot studies                     
                                unless source water                     
                                quality criteria                        
                                met.                                    
11/95..  ....................  ....................  NOA for monitoring 
                                                      data, direction of
                                                      interim ESWTR.    
1/96...  ....................  ....................  Systems>10k        
                                                      complete ICR      
                                                      monitoring. End   
                                                      NOA public comment
                                                      period.           
3/96...  ....................  Systems complete ICR  Systems>100k       
                                monitoring.           complete ICR      
                                                      monitoring.       
12/96..  Promulgate Stage 1..  ....................  Promulgate interim 
                                                      ESWTR for         
                                                      systems>10k.      
6/97...  ....................  Notice of             Propose long-term  
                                availability for      ESWTR for         
                                Stage 2 reproposal.   systems<10k,      
                                                      possible changes  
                                                      for systems>10k.  
10/97..  ....................  Complete and submit                      
                                results of bench/                       
                                pilot studies.                          
12/97..  ....................  Initiate reproposal--                    
                                begin with 3/94                         
                                proposal.                               
6/98...  Effective. Effective  Close of public       Interim ESWTR      
          for SW systems        comment period.       effective for     
          serving                                     systems>10k. 1994-
          greater>10k,                                6 monitoring data 
          extended compliance                         used to determine 
          date for GAC or                             treatment level.  
          membrane technology.                                          
12/98..  ....................  Propose for CWSs,     Publish long-term  
                                NTNCWSs.              ESWTR.            
6/00...  Stage 1 limits        Promulgate Stage 2    Long-term ESWTR    
          effective for         for all CWSs,         effective for all 
          surface water         NTNCWSs.              system sizes.     
          systems<10k, GW                                               
          systems>10k.                                                  
1/02...  Stage 1 limits        Stage 2 effective,                       
          effective for GW      compliance for GAC/                     
          systems<10k unless    membranes by 2004.                      
          Stage 2 criteria                                              
          supersede.                                                    
------------------------------------------------------------------------

    EPA is proposing to delay the effective date of the Stage 1 D/DBP 
regulations for systems serving less than 10,000 people until June 30, 
2000, to allow such systems time to comply with the long-term ESWTR. 
EPA believes that this date reflects the shortest time possible that 
would allow the long-term ESWTR to be proposed, promulgated, and become 
effective, thereby providing the necessary protection from any downside 
microbial risk that might otherwise result when systems of this size 
achieve compliance with the Stage 1 D/DBP rule.
    Since EPA is proposing the interim ESWTR before systems begin 
collecting the monitoring data specified by the ICR, the Agency's final 
direction for the interim ESWTR is not yet clear. For this reason, the 
Agency is proposing a number of regulatory alternatives, including one 
that would not revise the existing SWTR. After EPA receives and 
processes pertinent monitoring data generated under the ICR, the Agency 
will prepare a Federal Register notice (referred to as a Notice of 
Availability) that will present the processed data to the public, the 
Agency's interpretation of that data, and the specific regulatory 
strategy the Agency is considering. Public comments on this Federal 
Register package will influence the direction the Agency ultimately 
takes in developing the interim ESWTR.
    EPA is extending the comment period to the proposed interim ESWTR 
to May 30, 1996, which is beyond the original date indicated in Table 
I-1 (August 1994). The Agency believes this adjustment is necessary to 
take into account the slippage in the anticipated ICR promulgation 
date, which will necessarily also result in a slippage in the NOA 
publication date to early Spring 1996. The Agency believes that it 
would be more reasonable and efficient for EPA not to close the comment 
period for the ESWTR before the comment period ends for the NOA.
    Unlike the interim ESWTR, the long-term ESWTR will cover all 
surface water systems, including those serving fewer than 10,000 
people. The anticipated primary thrust of these final regulations will 
be to cover these smaller systems, rather than to make major changes in 
the treatment requirements for larger systems, although some 
refinements are possible. EPA expects the criteria for defining the 
specified treatment needed for smaller systems will be simpler than 
that for the larger systems and may, for example, only require 
monitoring of easily measured indicators rather than pathogens, 
especially if an adequate correlation is observed between indicator and 
pathogen densities under the ICR and other related research. Pathogen 
monitoring in small systems may be possible, if inexpensive, simple 
analytical tests for viruses and/or protozoa can be developed, 
evaluated, and approved. EPA may also cover small systems by using the 
ICR data to develop national occurrence patterns that would allow the 
Agency to establish more appropriate treatment criteria for small 
systems. The Agency anticipates that by characterizing source water 
quality using any one or a combination of these approaches, a small 
system could evaluate the adequacy of its existing level of treatment 
for pathogen control and determine the need for treatment 
modifications.
Data Collection and Monitoring
    If EPA decides to revise the SWTR to require higher levels of 
treatment for poorer quality source waters, information on microbial 
densities in these sources gathered under the ICR can be used by 
utilities, States and EPA to determine required levels of treatment for 
individual systems. If such information is not available for a system 
(e.g., if a system that had not performed ICR monitoring serves a 
community which grows in population from less than to greater than 
10,000 people), EPA would require such a system to collect sufficient 
information on microbial densities of its source water and treatment 
practices to allow the State to make this determination. The ESWTR may 
also require systems serving 10,000 people or greater to monitor their 
source waters periodically to determine whether changes have occurred 
in the quality of that water since the ICR monitoring. Any 
deterioration in source water quality may necessitate additional 
pathogen control measures.
    For monitoring subsequent to the ICR for Giardia and 
Cryptosporidium, EPA intends to require the use of the 
immunofluorescence method specified by the ICR. If performance data 
support their use, newer assays currently under development may be 
considered. One of these assays is based on the observation that 
particles in a rotating electric field also rotate if the frequency is 
right. Investigators using this principle have developed a novel assay, 
referred to as the electrorotation assay, that can apparently easily 
distinguish between the target organism (e.g., Cryptosporidium) and 
other organisms and particle debris if the field frequency is adjusted 
properly. At this frequency, the target organism rotates and other 
particles do not, an observation easily visualized under the 
microscope. Preliminary data reported by the developer for sterile 
natural water samples spiked with Cryptosporidium are similar to those 
obtained with an immunofluorescence method. If these data are 
confirmed, the assay would be far less expensive, simpler, and more 
rapid than the standard method.
    In addition to this assay, other potential assays for Giardia and 
Cryptosporidium include polymerase chain reaction (PCR) and flow 
cytometry. The PCR is a powerful and rapid tool for detecting genetic 
material that is initially present in very low concentrations. It 
involves the amplification of genetic material in a laboratory 
instrument until sufficient quantities are available for analysis. 
Recent publications have described the use of PCR in detecting Giardia 
and its potential for differentiating between live and dead cysts 
(Mahbubani, et al. 1991). Flow cytometry is a process that measures 
physical or chemical characteristics of cells passing single file 
through the measuring apparatus in a fluid stream (Shapiro, 1992). This 
process is rapid and may be useful for distinguishing between and 
quantifying Giardia and Cryptosporidium.

C. Proposed Maximum Contaminant Level Goal and Treatment

Technique for Cryptosporidium
    As stated above, the protozoan Cryptosporidium parvum has recently 
been implicated in a number of large waterborne disease outbreaks in 
the United States. The disease cryptosporidiosis is caused by ingestion 
of the environmentally-resistant oocysts of Cryptosporidium, which are 
readily carried by the waterborne route. Both human and other animals 
may excrete these oocysts. Transmission of this disease often occurs 
through ingestion of the infective oocysts from contaminated water or 
food, but may also result from direct or indirect contact with infected 
persons or animals. Symptoms of cryptosporidiosis include diarrhea, 
abdominal discomfort, nausea, vomiting, dehydration, weight loss, and 
other gastrointestinal symptoms (Current et al., 1983). These may 
persist for several days to several months. Young children and 
immunocompromised persons are most susceptible to infection (Wittenberg 
et al., 1989; De Mol et al., 1984), but people of all ages may become 
infected. While cryptosporidiosis is generally a self-limiting disease 
with a complete recovery in otherwise healthy persons, it can be very 
serious in immunosuppressed persons, such as persons with AIDS, those 
receiving treatment for certain types of cancer, and organ-transplant 
recipients (De Mol et al., 1984; CDC, 1982). Several studies in Great 
Britain have documented a waterborne route for cryptosporidiosis in 
AIDS patients and in persons receiving immunosuppressive transplant 
therapy (Casemore, 1990). There appears to be an immune response to 
Cryptosporidium, but it is not known if this results in protection 
(Fayer and Ungar, 1986). Data suggest that a person, once infected, can 
transmit this infection by direct contact to other susceptible persons 
(Casemore and Jackson, 1984).
    Between 1984-1993, there were a number of reported outbreaks of 
significant waterborne cryptosporidiosis in the U.S. and Great Britain, 
totaling many tens of thousands of cases (D'Antonio et al., 1985; Smith 
et al., 1988; Hayes et al., 1989; Herwaldt et al., 1991; Levine and 
Craun, 1990; Moore et al., 1993). The trend in numbers of outbreaks has 
been on the increase, probably due to greater recognition and 
subsequent reporting of Cryptosporidium in outbreaks during recent 
years. Prevalence data for human cryptosporidiosis in all age groups 
ranged from 1 to 2 percent in Europe, 0.6 to 4.3 percent for North 
America, and 3 to 20 percent for Asia, Australia, Africa, and South 
America (EPA, 1993). The role of water in the transmission of 
cryptosporidiosis has been proven. However, the known percentages of 
cases from water compared to other routes may substantially under-
represent the water route. The route of transmission for many cases of 
cryptosporidiosis was not determined, but may have been waterborne.
    During the spring of 1993, there was a severe waterborne disease 
outbreak of cryptosporidiosis in Milwaukee, Wisconsin, with an 
estimated 400,000 cases of diarrhea and apparently several deaths 
associated with the disease in severely immunocompromised persons. 
Another recent outbreak of waterborne cryptosporidiosis occurred in 
Jackson County, Oregon, during the winter and spring of 1992, where as 
many as 15,000 people (10% of the population) displayed 
cryptosporidiosis-like symptoms (AWWA, 1992).
    It is estimated that over 162 million people are served by public 
water systems using surface water, most of which are filtered and 
disinfected. Of these, as of June 1989, an estimated 21 million people 
were receiving unfiltered surface water that is only disinfected. EPA 
anticipates that, as a result of the SWTR, more than 80 percent of the 
unfiltered systems will install filtration. Nevertheless, in spite of 
filtration and disinfection, Cryptosporidium oocysts have been found in 
filtered drinking water (LeChevallier et al., 1991b; EPA, 1993) and 
most waterborne outbreaks of cryptosporidiosis have been associated 
with filtered surface water systems. Therefore, it appears that surface 
water systems that filter and disinfect may still be vulnerable to 
Cryptosporidium, depending on source water quality and treatment 
effectiveness. In addition, some surface water systems that were able 
to avoid filtration under the SWTR may need to filter to provide 
adequate protection against Cryptosporidium.
    EPA is proposing an MCLG for Cryptosporidium because 
Cryptosporidium oocysts have been demonstrated to be a significant 
health threat for all persons consuming untreated or inadequately 
treated surface waters and ground waters under the influence of surface 
waters. The proposed MCLG is based upon animal studies and the human 
epidemiology of waterborne outbreaks of cryptosporidiosis.
    While it is clear that Cryptosporidium can infect humans, dose-
response data for infection and illness rates are lacking. Therefore, 
risk assessments for this organism based on human data are not 
currently possible. However, the results of several animal studies have 
been published on the infectious dose of Cryptosporidium oocysts. 
Korich et al. (1990) examined neonatal mice inoculated with 600, 6,000, 
or 60,000 oocysts. In this study, the mean infectious dose (ID50) was 
determined by initial experiments to be 60 oocysts. Mice receiving 60 
or more oocysts were typically infected while those receiving less than 
60 oocysts often did not demonstrate any infection. The work of Miller 
et al. (1990), while limited because of the small number of animals 
tested, was conducted on Macaque monkeys. Ten oocysts via oral 
intubation were capable of causing infection and the signs and symptoms 
resembled the effects seen in children and immunocompromised humans 
with cryptosporidiosis. Feeding studies in mice described by Ernest et 
al. (1986) indicated that inoculation with 100, 500, or 1,000 oocysts 
caused infection in 22, 66, and 78 percent, respectively, of the mice 
in each dose group. Studies to date strongly suggest that there are 
strain differences or virulence factors that may greatly influence the 
ability of Cryptosporidium to infect humans and animals via the oral 
route. The comparative infectivity of specific strains for humans and 
various animal models has not been accurately established.
    The use of animal models for determining infectious dose may 
overestimate the number of oocysts required for human infection. Also, 
technical questions remain that affect EPA's consideration of the 
reliability and meaning of the available data. For example, the length 
of time and procedures used in storage of oocysts in the laboratory 
before infectivity studies begin may influence infectivity 
determinations. There are currently no proven in-vitro methods to 
determine whether oocysts used in testing are all viable.
    Because some strains of Cryptosporidium parvum appear to be highly 
infectious, and because there is no current generally accepted 
practical means for distinguishing whether detected oocysts are viable 
or for determining the infectious dose of any particular strain, EPA 
believes this organism should be assumed to be without an infectivity 
threshold for purposes of this rule. That is, consumption of one 
Cryptosporidium oocyst would be considered sufficient to initiate human 
infection as a possible consequence. Also, direct person-to-person 
spread of infection may readily occur, thus magnifying the significance 
of the original waterborne infection. Therefore, the presence of this 
organism at any level in consumed drinking water cannot be considered 
safe for human consumption. For these reasons and to be consistent with 
EPA drinking water standards for Giardia, enteric viruses, Legionella, 
E. coli and coliform bacteria, EPA proposes that the MCLG for 
Cryptosporidium oocysts in water be zero. Public comments are requested 
on this rationale for setting an MCLG of zero and a treatment technique 
for Cryptosporidium.

D. Proposed Revisions to SWTR Under all Treatment Alternatives

    This section proposes three revisions of the SWTR that would apply 
regardless of which of the four treatment alternatives in Section E 
that EPA selects. This section also requests public comment on several 
additional measures (Section 4, below).
1. Inclusion of Cryptosporidium in Definition of ``Groundwater Under 
the Direct Influence of Surface Water''
    The SWTR at 40 CFR 141.2 defines ``groundwater under the direct 
influence of surface water'' as ``any water beneath the surface of the 
ground with (1) significant occurrence of insects or other 
macroorganisms, algae, or large-diameter pathogens such as Giardia 
lamblia, or (2) significant and relatively rapid shifts in water 
characteristics such as turbidity, temperature, conductivity, or pH 
which closely correlate to climatological or surface water conditions * 
* *''. Systems using such ground waters as a source for drinking water 
are subject to the provisions of the SWTR. Determination of whether a 
ground water is under the direct influence of surface water requires 
careful evaluation of site-specific information on water quality, well 
construction characteristics, and hydrogeology.
    EPA defined groundwater under the direct influence of surface water 
in the SWTR to ensure that public water supply systems using this type 
of source water would provide appropriate treatment to minimize health 
risks from pathogens. Since viruses and bacteria are known to 
contaminate true ground waters, EPA focused attention on those 
contaminants that do not normally occur in true ground waters and whose 
presence suggests direct surface water contamination.
    Among those contaminants are certain pathogenic protozoa, such as 
Cryptosporidium parvum and Giardia lamblia. These protozoa are common 
in surface waters. At the time of promulgation of the SWTR, routine 
methods for detection of Cryptosporidium were not generally available 
and, therefore, Cryptosporidium was not specifically addressed under 
the definition of ``groundwater under the direct influence of surface 
water''. EPA is currently revising its existing guidance (EPA, 1991a; 
EPA, 1992) to address this issue.
    EPA proposes to amend the SWTR by including Cryptosporidium in the 
definition of a ``ground water under the direct influence of surface 
water''. Under the rule, a system using ground water considered 
vulnerable to Cryptosporidium contamination would be subject to the 
provisions of the SWTR. The Agency proposes that this determination be 
made by the State for individual sources using State-established 
criteria for requirements and documentation. The Agency believes that 
this would allow States sufficient flexibility to accommodate local and 
regional hydrogeological conditions and maintain consistency with State 
well construction requirements, watershed management policies, and 
wellhead protection plans.
    Because Cryptosporidium can occur episodically, the inability to 
detect this organism in a ground water at any given time would not 
necessarily suggest that ground water is not under the direct influence 
of surface water. The presence of Cryptosporidium, however, would 
indicate fecal contamination and direct influence of surface water.
    The SWTR does not necessarily require a system that uses ground 
water to filter if it detects Cryptosporidium, Giardia, or other 
contaminants associated with surface water in the ground water, or if 
the groundwater is categorized as being under the direct influence of 
surface water. The presence of these organisms may be the result of 
faulty well construction that can be remedied by inexpensive measures. 
Also, the rule allows States to grant removal/inactivation credit for 
the ``natural disinfection'' achieved during flow from the surface 
water source to a well; such natural disinfection could mitigate the 
treatment level that might otherwise be required. For the State to 
grant removal/inactivation credit for a system, that system would have 
to demonstrate the extent to which Giardia and Cryptosporidium are 
removed by site-specific natural removal processes before the water 
enters the well.
    However, strategies for granting such credits are currently limited 
because accurate pathogen removal/inactivation rates during transport 
through the ground cannot yet be easily predicted.
    EPA solicits comment on the inclusion of Cryptosporidium in the 
determination of ground water under the influence of surface water, on 
the larger consideration of revisions to guidance on this issue, and on 
the most appropriate procedures for determining removal/inactivation 
credits and treatment requirements for systems using ground waters 
under the direct influence of surface water.
2. Inclusion of Cryptosporidium in Watershed Control Requirements
    The SWTR at Sec. 141.71 specifies the conditions under which a 
public water system using a surface water source can avoid filtration. 
Among the conditions is a requirement that the system maintain a 
watershed control program that minimizes the potential for source water 
contamination by Giardia lamblia and viruses (Sec. 141.71(b)(2)). This 
program must include a characterization of the watershed hydrology 
characteristics, land ownership, and activities which may have an 
adverse effect on source water quality.
    EPA is proposing to extend the watershed control requirements to 
include the control of Cryptosporidium in the source water in a manner 
analogous to the existing requirements in Sec. 141.71(b)(2) for Giardia 
cysts and viruses. The rationale is that Cryptosporidium is a pathogen 
that cannot be easily controlled with conventional disinfection 
practices, and therefore its presence in source water serving 
unfiltered surface water systems must be limited. Specifically, 
Cryptosporidium would be included in the watershed protection control 
provisions wherever Giardia is mentioned.
3. Sanitary Surveys for all Surface Water Systems
    The SWTR at Sec. 141.71(b)(3) requires that systems wishing to 
avoid filtration must be subject to an annual on-site inspection 
performed by the State or a party approved by the State. The results of 
this system inspection must indicate to the State's satisfaction that 
the disinfection treatment process and the watershed control program 
are adequately designed and maintained.
    EPA proposes to amend the SWTR to require all systems that use 
surface water, or ground water under the direct influence of surface 
water, to have a periodic sanitary survey, regardless of whether they 
filter or not. States would be required to review the results of each 
sanitary survey to determine whether the existing monitoring and 
treatment practices for that system are adequate, and if not, what 
corrective measures are needed to provide adequate drinking water 
quality. If EPA publishes a regulation that requires systems to treat 
their water on the basis of pathogen densities in the source water (see 
Section E below), the Agency would require systems, as part of the 
sanitary survey, to assess quantitatively whether the source water 
quality has changed sufficiently since the previous sanitary survey to 
warrant changes in treatment practice.
    Under this rule, the system would be responsible for insuring that 
the sanitary survey is accomplished. Only the State or an agent 
approved by the State would be able to conduct this sanitary survey, 
except in the unusual case where a State has not yet implemented this 
requirement, i.e., the State has neither performed a sanitary survey 
nor generated a list of approved agents. For these unusual cases, the 
Agency solicits comment on what EPA prerequisites, if any, should be 
specified in the rule or guidance for individuals performing sanitary 
surveys (e.g., BS degree in environmental engineering, professional 
engineer certificate, sanitarians, etc.).
    Sanitary surveys are defined in Sec. 141.2 as ``an on-site review 
of the water source, facilities, equipment, operation and maintenance 
of a public water system for the purpose of evaluating the adequacy of 
such sources, facilities, equipment, operation and maintenance for 
producing and distributing safe drinking water.'' Guidance for 
conducting a sanitary survey for unfiltered systems appears in the SWTR 
Guidance Manual (EPA, 1991), even though such a survey is not 
specifically required by the SWTR. EPA solicits comment on how this 
Guidance Manual should be revised to address concerns for filtered 
systems, and for Cryptosporidium.
    The requirement for a sanitary survey under this rule would be 
similar to that in the TCR, which requires periodic sanitary surveys 
for some systems. Specifically, the TCR at Sec. 141.21(d) requires 
periodic sanitary surveys for systems that collect fewer than five 
routine samples per month. These surveys are performed by the State or 
a party approved by the State. The results of the sanitary surveys are 
to be used by the State to determine whether the monitoring frequency 
is appropriate, and if not, what the new frequency should be and 
whether the system needs to undertake any specific measures to improve 
water quality. These surveys are to be performed every five years or 
ten years, depending on circumstances. These surveys are somewhat more 
extensive than the on-site inspection required under the existing SWTR 
and include an evaluation of the distribution system.
    In addition to the sanitary survey in the TCR and the proposed 
requirement for surface water systems, EPA intends to propose a 
sanitary survey requirement in the forthcoming Groundwater Disinfection 
Rule for all public water supply systems using groundwater that wish to 
avoid disinfection.
    The Agency believes that periodic sanitary surveys, along with 
appropriate corrective measures, are indispensable for assuring the 
long-term quality and safety of drinking water. Many States already 
perform sanitary surveys on most or all systems. By taking steps to 
correct deficiencies exposed by a sanitary survey, the system provides 
an additional barrier to microbial contamination of drinking water.
    Compliance with this requirement would not eliminate the 
requirement for unfiltered systems to conduct annual on-site 
inspections, although applicable information from these on-site 
inspections could be used to satisfy some elements of the sanitary 
survey. During the years when the sanitary survey is conducted, the 
sanitary survey would fulfill the on-site inspection requirement.
    With promulgation of these rules, EPA hopes to focus more attention 
on watersheds and watershed protection activities to enhance and 
maintain the quality of both surface waters and ground waters as 
sources for drinking water. The Agency recognizes that in many areas of 
the United States, watersheds that serve as drinking water sources are 
increasingly vulnerable to degradation. Moreover, the current status of 
technology and scarce funding may limit the levels of water treatment 
reasonably possible. Therefore, the Agency wishes to minimize the 
contamination of source waters to maintain or improve the health 
benefits from drinking water treatment. While the rule proposed here 
derives from provisions of the SDWA, protection of watersheds is also 
consistent with provisions of the Clean Water Act.
    One issue that the Negotiating Committee considered throughout the 
negotiation process was the relationship and role of watershed 
protection to these regulations. The committee sought to promote 
watershed protection and to provide incentives to establish new 
watershed protection programs and to improve existing ones. This goal 
was prompted by the benefits that watershed protection provides not 
only for disinfectant byproduct control, but for the control of a wide 
range of potential drinking water contaminants.
    Watershed protection minimizes pathogen contamination in water 
sources, and hence the amount of physical treatment and/or disinfectant 
needed to achieve a specified level of microbial risk in a finished 
water supply. It also may reduce the level of turbidity, pesticides, 
volatile organic compounds, and other synthetic organic drinking water 
contaminants found in some water sources. Watershed protection results 
in benefits for water supply systems by minimizing reservoir 
sedimentation and eutrophication and by reducing water treatment 
operation and maintenance costs. Watershed protection also provides 
other environmental benefits through improvements in fisheries and 
ecosystem protection.
    The types of watershed programs that the committee wished to 
encourage are those that consider agricultural controls, silvicultural 
controls, urban non-point controls, point discharge controls, and land 
use protection that are tailored to the environmental and human 
characteristics of the individual watershed. These characteristics 
include the hydrology and geology of the watershed; the nature of human 
sources of contaminants; and the legal, financial and political 
constraints of entities that affect the watershed.
    Sanitary survey frequency. EPA is considering requiring sanitary 
surveys either every three years or every five years, and requests 
public comment on this issue. There is a major concern that changes 
over time in watershed characteristics, such as those resulting from 
development or other changes in land use, may degrade surface source 
water quality significantly. Treatment facilities and distribution 
systems likewise may deteriorate over time. It is important to address 
such adverse changes as soon as possible. Consequently, more frequent 
sanitary surveys should result in safer and more reliable drinking 
water. This is the advantage of a three-year survey over a five-year 
survey.
    Yet a survey every five years is less expensive and is more 
consistent with the provisions of the TCR. EPA considers a five-year 
frequency to be minimal for assessing watershed and system conditions 
associated with surface waters. To provide adequate lead time to the 
State for implementing any sanitary survey requirement, EPA would not 
require systems to complete the initial sanitary survey until five 
years after the effective date of this rule. This lead time would not 
apply to systems that collect fewer than five samples per month under 
the TCR, since they should already have had their initial survey.
    EPA does not believe this sanitary survey requirement would be 
onerous to systems, since systems collecting fewer than five samples/
month (i.e., serving fewer than 4101 people) are already required to 
conduct sanitary surveys under the TCR, and larger systems should have 
greater financial resources than these smaller ones.
4. Possible Supplemental Requirements
    a. Uncovered Finished Water Reservoirs. EPA guidelines recommend 
that all finished water reservoirs and storage tanks be covered (EPA, 
1991a,b). The American Water Works Association (AWWA) also has issued a 
policy statement strongly supporting the covering of reservoirs that 
store potable water (AWWA, 1993). In addition, a workshop in 1981 
convened by EPA, in conjunction with the American Society for 
Microbiology, to advise EPA on a variety of drinking water issues 
recommended that EPA require systems to cover all new finished water 
reservoirs (EPA, 1983). By covering reservoirs and storage tanks, 
systems would reduce the potential for contamination of the finished 
water by pathogens and hazardous chemicals. It would also limit the 
potential for taste and odor problems and increased operation and 
maintenance costs resulting from environmental factors such as sunlight 
(Bailey and Lippy, 1978).
    Potential sources of contamination to uncovered reservoirs and 
tanks include airborne chemicals, surface water runoff, animal 
carcasses, animal or bird droppings, growth of algae and other aquatic 
organisms due to sunlight that results in biomass, and violations of 
reservoir security (Bailey and Lippy, 1978).
    Because of these adverse consequences, EPA is considering whether 
to issue regulations that require systems to cover finished water 
reservoirs and storage tanks. The Agency solicits public comment on 
whether such a national regulation is appropriate, whether such a 
requirement should be at State discretion only, what costs would be 
incurred by systems under such a regulation, and under what conditions 
a waiver from this rule would be appropriate.
    Cross-Connection Control Program. Plumbing cross-connections are 
actual or potential connections between a potable and non-potable water 
supply (EPA, 1989b). According to Craun (1991), 24% of the waterborne 
disease outbreaks that occurred during 1981-1990 were caused by water 
contamination in the distribution system, primarily as the result of 
cross-connections and main repairs. During this period, 11 reported 
outbreaks with 1350 associated cases were blamed on cross-connection 
problems in community water systems (Craun, 1994). While the vast 
majority of outbreaks associated with cross connections are caused by 
pathogens, a few are caused by chemicals.
    EPA does not have a regulation mandating a cross-connection control 
program, but does address the issue in the TCR. Section 141.63(d)(3), 
for example, identifies proper maintenance of the distribution system 
as one of the best technologies, treatment techniques, and other means 
for achieving compliance with the MCL for total coliforms. In a 
subsequent clarification, EPA explained that this statement in the rule 
includes a cross-connection control program. In addition, in a rule 
that stayed the no variances provision of the TCR, i.e., allows States 
to grant variances, EPA recommended that one of the criteria that 
States could use to identify systems that could operate under a 
variance without posing an unreasonable risk to health was that the 
system has a cross-connection control program acceptable to the State 
and performs an audit of its effectiveness (56 FR 1556, January 15, 
1991). The AWWA also has a policy statement on cross connections urging 
systems to set up a program for their control (AWWA, 1993).
    EPA is seeking public comment on whether EPA should require States 
and/or systems to have a cross-connection control program; what 
specific criteria, if any, should be included therein; and how often 
such a program should be evaluated. Should EPA require that only those 
connections identified as a cross connection by the public water system 
or the State be subject to a cross connection program? EPA also seeks 
comment on what conditions would a waiver from this rule be 
appropriate. In addition, the Agency requests commenters to identify 
other regulatory measures EPA should consider to prevent the 
contamination of drinking water already in the distribution system 
(e.g., minimum pressure requirements in the distribution system).
    State notification of high turbidity levels. The SWTR requires 
filtered systems to report turbidity measurements to the State within 
ten days after the end of each month the system serves water to the 
public (Sec. 141.75(b)(1)). If at any time the turbidity exceeds 5 NTU, 
however, the system must notify the State as soon as possible, but no 
later than the end of the next business day (Sec. 141.75(b)(3)(ii)). In 
addition, the system must notify the public as soon as possible, but in 
no case later than 14 days after the violation (non-acute violation, 
Sec. 141.32(a) and Sec. 141.32(b)(10)).
    EPA is considering broadening the requirement for systems to notify 
the State as soon as possible. The Agency might, for example, require 
systems to notify the State as soon as possible if at any point during 
the month it becomes apparent that a system will exceed the monthly 
turbidity performance standard in Sec. 141.73 (0.5 NTU for conventional 
filtration or direct filtration, 1 NTU for slow sand filtration or 
diatomaceous earth) for an extended period of time (e.g., more than 12 
consecutive hours), regardless of whether the system will violate the 
monthly standard. In addition, the Agency might require systems to 
notify the State as soon as possible if at any point during the month 
it becomes apparent that a system will violate the monthly turbidity 
performance standard in Sec. 141.73, rather than await the end of the 
month, as specified in the existing SWTR.
    There are sound public health reasons for requiring swift State 
notification for persistent turbidity levels above the performance 
standards in Sec. 141.73. Pathogens may accompany the turbidity 
particles that exit the filters, especially with poor quality source 
waters. High turbidity levels in the filtered water, even for a limited 
time, may represent a significant risk to the public. Increasing the 
disinfection residual in such cases is essential, but some pathogens 
(e.g., Giardia and Cryptosporidium) are relatively resistant to 
disinfection. Early notification would allow the states to require the 
system to issue an immediate public notice of the turbidity violation 
if the nature of the violation is considered to be an immediate health 
concern.
    EPA solicits comment on whether the Agency should require systems 
to notify the State as soon as possible for persistent turbidity levels 
above the performance standards or for any other situation that is not 
now a violation of the turbidity standards.

E. Alternative Treatment Requirements

    This section proposes five alternative treatment requirements for 
removing Giardia, Cryptosporidium, and/or viruses. The final rule might 
include one or some combination of these alternatives. These regulatory 
alternatives would require systems to remove a specified level of 
pathogen based upon its density in the raw water, as measured either 
under the ICR or another comparable approach. The greater the pathogen 
density in raw water, the greater would be the pathogen reduction 
required by treatment. This section also examines several statistical 
options for defining pathogen densities in source waters.
    The Regulatory Impact Analysis for this proposal includes 
preliminary estimates of the incremental costs for several of these 
options and discusses what incremental risk reductions would be needed 
to offset these costs from a cost benefit perspective. As the ICR data 
become available, EPA intends to develop the risk reduction and cost 
estimates of these different options for defining pathogen densities in 
source waters, for different treatment alternatives, and to publish 
this analysis in a Notice of Availability. After reviewing public 
comments and additional information and data, EPA intends to select one 
or more options that provides the greatest improvement in public health 
taking into account any adverse health effects associated with 
treatment strategies required and the costs of these improvements.
1. Options for Defining Pathogen Densities in Source Waters
    EPA is considering several options for defining the raw water 
pathogen density that systems would use to determine their needed level 
of treatment. As part of this, EPA is considering both the technical 
and public health implications of these options.
    The public health risk from waterborne microorganisms depends on 
their density in source water and their infectious dose levels. Since 
the calculated infectious dose levels for Giardia and other pathogens 
do not address high-risk populations, e.g., the very young and old and 
immunocompromised individuals, they may not be conservative with 
respect to protecting public health. Therefore, EPA could provide a 
margin of safety for such populations by requiring a system to define 
the pathogen density used for determining the required treatment level 
in terms of a conservative statistical method, i.e., one that would 
provide a higher pathogen density than an arithmetic mean. Such 
analysis would also need to consider various assumptions regarding the 
likelihood of a detected organism being viable and infectious. 
Currently it is not yet possible to determine whether a protozoan cyst 
in water is viable or, if viable, infectious. EPA and other groups, 
however, are conducting research in this area.
    The approach EPA selects for calculating pathogen density should 
consider the wide temporal and spatial variations in densities that 
occur in raw water and should be appropriate for the calculation of the 
attendant health risks. Among the approaches being considered by the 
Agency are the arithmetic mean, geometric mean, 90th percentile, and 
maximum measured value. These are discussed below.
    EPA expects that systems subject to this rule will use their data 
collected under the ICR as a basis for determining source water 
pathogen densities and selection of appropriate treatment levels. The 
Negotiating Committee recommended this approach so that systems would 
have sufficient time to determine the need for, design, and install any 
necessary treatment to comply with both the ESWTR and D/DBPR 
requirements in a consistent, integrated manner. This approach would 
require States, as part of their primacy applications for the ESWTR, to 
include provisions for acquiring ICR data from EPA's ICR data base when 
it becomes available, directly from the system or a database.
    EPA recognizes that some systems that currently serve fewer than 
10,000 people, and thus not subject to ICR monitoring, may eventually, 
as a result of their growth, become subject to the interim ESWTR. Once 
such a system serves 10,000 people or more, the rule would require it 
to collect data sufficient to determine the source water pathogen 
densities in a manner analogous to that specified in the ICR. The 
system would then use these data to determine the level of treatment 
needed. EPA solicits comment on this approach.
    a. Use of arithmetic mean of data. The arithmetic mean is the sum 
of the pathogen densities from all collected samples divided by the 
number of samples. An arithmetic mean would be calculated for each 
pathogen. The arithmetic mean is most appropriate when the densities 
are relatively uniform, both spatially and temporally, and symmetrical 
about the mean.
    Use of the arithmetic mean is most useful when the distribution of 
measured values approximates a normal distribution. Relative to the 
geometric mean, the arithmetic mean allows an easier calculation of 
confidence intervals and may be more conservative. When considering the 
multiple exposures associated with drinking water ingestion at the low 
microbial risk levels associated with treated water, risks can be 
considered as additive and linearly related. Under these circumstances, 
the arithmetic mean is superior to the geometric mean in the estimation 
of central tendency (Regli et al., 1991).
    b. Use of geometric mean of data. The geometric mean is defined by 
the equation:

Gm=log-1 (1/n x [log X1+log X2+...log Xn]),

Where n = number of samples and Xi is the measured density for 
each sample. For example, the geometric mean of the values 1, 10, and 
100 would be 10. The geometric mean is more appropriate than the 
arithmetic mean for representing the central tendency for data that 
have a skewed distribution. However, the geometric mean is less 
conservative, i.e., it would generally estimate a lower mean density 
and therefore lower risk for pathogens than the arithmetic mean (for 
example, the arithmetic mean of 1, 10, and 100 is 37, versus the 
geometric mean of 10). Nevertheless, depending upon the assumptions 
made in the risk assessment calculation (e.g., percentage of cysts/
oocysts viable), use of the geometric mean may be adequately 
conservative for estimating exposures and consequently appropriate 
levels of treatment (Regli et al., 1991).
    c. Use of the 90th percentile value. Another alternative for 
defining pathogen density is to base this value on the 90th percentile 
of all data for a particular pathogen. This is the value below which 
fall 90% of the data points and above which fall 10% of the data 
points. This approach is more conservative in terms of risk than the 
arithmetic mean and geometric mean, because for sources where pathogen 
density varies significantly throughout the year, use of this value 
will be more representative of the elevated risk associated with peak 
contamination periods.
    Use of the 90th percentile measured value, however, has the obvious 
drawback that it requires a sufficient number of samples to provide a 
good 90th percentile estimate without interpolation. In many cases, 
particularly for small water systems, cost considerations will prevent 
extensive sampling. For example, the proposed ICR would require only 
six raw water samples over the period of a year for systems from 10,000 
to 100,000 people served. The 90th percentile value could be 
interpolated from the two highest values.
    d. Use of the maximum measured value. This approach would dictate 
the use of the highest density measured under the ICR for raw water. 
Since few systems have the resources for routine, frequent, and long-
term sampling for pathogens such as Giardia, Cryptosporidium and 
viruses, it is clear that episodic periods of microbial contamination 
may escape detection. EPA is particularly concerned with the risks from 
unusually high level contamination events that might exceed the 
removal/inactivation capacity of a treatment system. While the maximum 
measured value may not be representative of the normal pathogen density 
in a source water, it would be more indicative of potential short-term 
risks.
    Additionally, since the published dose-response values for Giardia 
and other pathogens were developed in healthy adult populations and 
therefore are not conservative with respect to protecting public 
health, EPA might select use of the maximum value, which is the most 
conservative statistical option, to offset this problem. Alternatively, 
it may be more appropriate to use a less conservative method for 
estimating microbial densities but to use more conservative criteria 
for deriving the actual level of treatment requirements as they relate 
to pathogen densities. For example, if EPA assumes that all Giardia 
cysts detected are viable and infectious to humans in specifying the 
level of treatment needed, this approach may be sufficiently 
conservative to warrant the density calculation by one of the other 
above described methods.
    A major problem with basing the density calculation on the maximum 
value is that if a utility collects more than the minimum number of 
samples required in the interest of better defining potential 
exposures, it has a greater likelihood of collecting a sample with a 
higher pathogen density than would occur with the minimum required 
number of samples. In this case, the system may face a more stringent 
(and thus more expensive) standard.
    Use of the maximum measured density may be more appropriate than 
other statistical methods for systems that have not collected 
sufficient data to allow calculation of an adequately representative 
mean value or 90th percentile value. With such limited data, the 
maximum value might be suitable for determining level of treatment.
    EPA is soliciting comment on which approach is most appropriate for 
defining pathogen density. The Agency is also requesting comment on 
whether the approach used should be based on the number of pathogen 
samples collected, i.e., the maximum measured value would be required 
for systems taking only six samples under the ICR (systems serving 
between 10,000 and 100,000 people) and 90th percentile value for 
systems that collect at least 10 samples.
    2. Treatment alternatives for controlling pathogens. To determine 
what regulatory controls are most appropriate for controlling pathogens 
in drinking water, EPA must decide what constitutes acceptably safe 
drinking water. The SDWA frames this discussion in determining MCLGs 
and MCLs. MCLG levels, which are not legally enforceable, are based 
solely on health concerns. As required by the SDWA, they are set ``at 
the level at which no known or anticipated adverse effects on the 
health of persons occur and which allows an adequate margin of 
safety''. The corresponding enforceable regulation consists of either 
an MCL set as close to the MCLG as feasible, taking cost and 
availability of treatment into account; or, when it is not 
technologically or economically feasible to monitor for the 
contaminants, a treatment technique(s) to achieve an acceptable risk.
    The SWTR promulgated an MCLG for Giardia of zero, i.e., no Giardia 
cysts should be allowed in drinking water. A system using surface water 
cannot usually attain this goal in any practical sense. Therefore, the 
SWTR preamble suggested a more practical health goal for Giardia: 
drinking water should not cause more than one Giardia lamblia infection 
annually per 10,000 exposed persons (10-4 risk). In contrast to 
this goal, EPA policy for specific chemical carcinogens is for 
theoretical lifetime upper bound risks to be no greater than within a 
range of 10-4 to 10-6. For non-carcinogenic chemical 
contaminants, EPA policy is to base the MCLG on the reference dose 
(RfD) for the given chemical. The RfD is calculated to be below any 
known level of exposure resulting in adverse health effects, so that 
drinking water at the resulting MCLG over a lifetime should be without 
known risk.
    In developing the D/DBP rule (proposed elsewhere in today's Federal 
Register), EPA is attempting to ensure that drinking water remains 
microbiologically safe at the limits set for disinfectants and 
byproducts, and that the disinfectants and byproducts themselves do not 
pose an unacceptable risk at these limits.
    Based on data on microbial illness and death in the U.S. compiled 
by Bennett et al. (1987), the estimated annual risk of waterborne 
illness during 1985 was about 4 x 10-3 and the estimated lifetime 
risk of death was about 3 x 10-4. As stated above, the goal of the 
SWTR was for systems to achieve a risk of less than 10-4 
infections per year for Giardia. Because Giardia is relatively 
difficult to inactivate compared to virus and bacterial pathogens, the 
SWTR assumed that water treatment adequate to achieve a 10-4 risk 
for Giardia would provide an even higher level of protection against 
pathogenic viruses and bacteria in untreated surface waters. Applying 
the Bennett et al. (1987) data regarding the ratio of mortality to 
waterborne illness (0.1 percent = 10-3), if a system achieves an 
incidence of 10-4 waterborne infections per year or less, the 
associated lifetime risk of death would be less than 7 x 10-6. 
This is a 40-fold decrease in risk relative to those estimated by 
Bennett et al. (1987), who used 1985 data.
    The above calculations refer to the average individual and an 
average pathogenic organism. Available dose-response data show that the 
risk of infection for a given pathogen density in the consumed water 
ranges over several orders of magnitude for different organisms (Regli 
et al., 1991). Setting a generic microbiological drinking water 
standard based on one dose-response curve will either overestimate or 
underestimate risks from other organisms. The risk of death from 
infection likewise varies widely with the organism (Bennett et al., 
1987). Therefore, the severity of the illness associated with a given 
organism must be considered.
    Additional considerations in assessing acceptable waterborne 
microbial risks involve the human subpopulations sensitive to 
infection, illness and death. Infection does not always result in 
illness; many infections are asymptomatic (Rendtorff, 1954; Lopez et 
al., 1980). The progression and severity of illness following microbial 
infection are more a function of individual physiology than the 
magnitude of dose, as is true for many toxic chemicals. Acute 
gastrointestinal illness, the most common microbial illness, is 
generally considered non-life threatening in normally healthy adults. 
However, this is not necessarily true for those subpopulations that are 
more sensitive to microbial infection or illness. Some studies (Glass 
et al., 1991; Lew et al., 1991) indicate that infants and those over 70 
years old have mortalities of 3-5 percent from diarrhea requiring 
hospitalization. As discussed above, Cryptosporidium infections, mild 
in healthy persons, are sometimes fatal to the immuno-compromised. 
Other identified sensitive human subpopulations include pregnant women 
and those with cardiovascular disease. EPA estimates that about 15% of 
the U.S. population is in these higher risk groups.
    Prudent health policy would be to protect these groups from their 
higher risks of waterborne microbial infection. Use of a one percent 
mortality-to-illness rate (instead of a 0.1 percent) to represent more 
deadly organisms and a 10-fold uncertainty factor (as used in EPA's RfD 
calculations) to account for these sensitive subpopulations may be 
appropriate for estimating potential risks resulting from systems 
achieving regulatory goals. A risk calculation based on this approach, 
assuming that the system achieves the risk goal of 10-4 annual 
infections for the average population, might result in a 7 x 10-5 
(i.e., 10-4 x 10-2 x 70 years) lifetime risk of death for 
certain subpopulations. The 7 x 10-5 lifetime risk of death (which 
is a more severe endpoint than cancer) is barely within the 10-4-
10-6 guideline for excess lifetime cancer risk that EPA uses for 
regulating chemical carcinogens in drinking water.
    These calculations, while based on estimates and approximations and 
having large uncertainties, suggest that the risk level of 10-4 
annual infections may be acceptable, albeit barely so. If EPA were to 
accept a more stringent annual risk level of 10-5 or 10-6 
infections to achieve a greater consistency between lifetime mortality 
risks from waterborne pathogens and most regulated drinking water 
chemicals, substantial increases in treatment might be required. EPA 
solicits comment on the appropriateness and magnitude of specific 
acceptable risk levels for microbial infection and illness.
    To counter waterborne illness, EPA is proposing five treatment 
alternatives for controlling Giardia, Cryptosporidium, and/or viruses. 
Within each alternative, several options are addressed. The Agency may 
promulgate one or more of these alternatives. Alternative A addresses 
enhanced treatment for Giardia only. Alternatives B and C address 
treatment for Cryptosporidium only. Alternative D addresses enhanced 
treatment for viruses only. Alternative E maintains existing level of 
treatment requirements for Giardia and viruses. EPA requests comment on 
what alternative(s) is most suitable.
    a. Alternative A. Enhanced treatment for Giardia. This alternative 
bases the extent of treatment required on the Giardia density in the 
source water. The SWTR currently requires a 99.9 percent (3-log) 
removal/inactivation of Giardia for all surface waters, regardless of 
Giardia cyst concentration in the source water. As discussed above and 
in the SWTR, EPA believes that for source waters of high quality (low 
pathogen densities), this level of treatment should result in less than 
one case of giardiasis (and most other waterborne disease) per 10,000 
people per year. This risk level for Giardia is associated with an 
infectious Giardia cyst density in the source water of less than one 
cyst/100 liters and assumes that 3 logs of removal/inactivation is 
consistently achieved on such source water. For more information about 
Giardia risk calculations and associated uncertainties and assumptions, 
refer to Rose et al. (1991), Regli et al. (1991), and Macler and Regli 
(1993).
    Under Alternative A, systems using source waters with higher 
Giardia densities would be required to meet higher levels of treatment 
to satisfy the desired acceptable risk level, e.g., the annual 
10-4 risk or perhaps a more stringent goal. Specifically, under 
one option of alternative A, EPA is proposing that systems meet the 
level of treatment for Giardia associated with the following Giardia 
concentrations in the source water to achieve a 10-4 annual risk 
level:

------------------------------------------------------------------------
                                                     Required treatment 
               No. of giardia/100L                    level (percent)   
------------------------------------------------------------------------
<1...............................................  99.9 (3-log).        
1-9..............................................  99.99 (4-log).       
10-99............................................  99.999 (5-log).      
>99..............................................  99.9999 (6-log).     
------------------------------------------------------------------------

    The determination by utilities and States of removal and 
inactivation efficiencies for specific treatment strategies would be 
based on EPA guidance and information, as is currently done under the 
existing SWTR. EPA would revise the existing SWTR Guidance Manual based 
on data collected under the ICR and research to complement any criteria 
promulgated under the ESWTR. The Agency expects that data collected 
under the ICR will be used by States and utilities to define the source 
water concentration and consequently the appropriate level of treatment 
for individual systems. If a utility has not collected data on pathogen 
densities in source water under the ICR, it would be required to do so 
to define the appropriate level of treatment.
    Depending on the method used for calculating pathogen density, 
assumptions used for estimating risk (e.g., whether to assume that all 
or only a portion of the detected cysts in the source water are viable 
and infectious to humans), the desired acceptable risk level, concern 
about DBP risk, and the technical and economic feasibility of achieving 
different levels of treatment, it may be appropriate to specify 
treatment requirements that address higher source water pathogen 
concentrations than described above. EPA is not aware to what extent 
physical removal greater than 2.5 logs can reasonably be achieved by 
systems using conventional water treatment approaches commonly 
practiced in the United States. The Agency believes that systems that 
optimize their treatment may be able to achieve substantially higher 
levels of removal. Membrane filtration techniques, although promising 
for much higher levels of removal, may not yet be technologically or 
economically feasible for large numbers of systems. The balance of the 
removal/inactivation requirement may have to rely on the use of 
chemical disinfectants. However, while EPA has confidence in the use of 
disinfectants to achieve current SWTR requirements, it has not been 
demonstrated that CT values extrapolated from tables in the SWTR or 
other sources are valid for higher levels of disinfection (e.g., to 
achieve a 4- or 5-log reduction of Giardia). EPA requests comment on 
approaches to achieve higher levels of treatment by physical means and 
on the use of existing CT values in the EPA guidance (EPA, 1991) to 
predict, by extrapolation, higher levels of inactivation that could be 
achieved by disinfection.
    EPA is considering an alternative version of the above described 
treatment requirements that would instead require greater Giardia 
reductions for source waters beginning with Giardia concentrations of 
10 or more cysts/100 liters, as indicated below:

------------------------------------------------------------------------
                                                     Required treatment 
                 No. giardia/100L                     level (percent)   
------------------------------------------------------------------------
10-99............................................  99.99 (4-log).       
100-999..........................................  99.999 (5-log).      
>1000............................................  99.9999 (6-log).     
------------------------------------------------------------------------

    EPA solicits comment on the two treatment options described above 
and on associated variations.
    b. Alternative B. Specific treatment for Cryptosporidium. EPA is 
proposing a treatment technique rather than an MCL for Cryptosporidium, 
because EPA believes that it is not currently economically or 
technologically feasible for a system to monitor for this organism in 
the finished water to determine whether it meets an acceptable risk 
level. The Agency bases its belief on three factors: (1) The 
variability of Cryptosporidium spatially and temporally may be 
considerable, and consequently systems would have to collect frequent 
samples and inordinately large sample volumes to properly characterize 
the density of this organism, (2) current methods for Cryptosporidium 
analysis are difficult and expensive, (3) it is not yet possible to 
predict the risk resulting from a specific level of exposure to 
Cryptosporidium, and (4) even if Cryptosporidium could be detected at 
the lowest concentrations of concern in the finished water, the 
exposure and associated risk would have already occurred, thereby 
reducing the significance of monitoring non-compliance.
    Under this rule, all community and non-community public water 
systems using any surface water source, or groundwater under the direct 
influence of surface water, would be required to treat these sources as 
described below. EPA anticipates that human dose-response data for 
Cryptosporidium will be available within the next year and will include 
these data in a Notice of Availability, probably in March 1996. Because 
they are not yet available, basing the treatment level on a specific 
acceptable risk level, as proposed by EPA for Giardia, cannot be used 
for Cryptosporidium in the present notice. Data collected to date 
suggest that the dose-response for Cryptosporidium may be similar to 
that for Giardia. If this is true, then the required reduction level 
for Cryptosporidium may be the same as for Giardia to achieve an 
equivalent risk level for similar source water densities.
    In the absence of dose-response data, EPA is proposing a wide 
variety of options. One sub-alternative would be to base the level of 
treatment on the Cryptosporidium densities found in the source water, 
as presented in the Table below. 

------------------------------------------------------------------------
                                                     Required treatment 
            No. cryptosporidium/100L                  level (percent)   
------------------------------------------------------------------------
<1...............................................  99.9 (3-log).        
1-9..............................................  99.99 (4-log).       
10-99............................................  99.999 (5-log).      
>99..............................................  99.9999 (6-log).     
------------------------------------------------------------------------

    EPA is concerned, however, that it may not be technologically or 
economically feasible to achieve the treatment levels above, given that 
Cryptosporidium is much more resistant to disinfection than is Giardia. 
Conventional treatment of coagulation, sedimentation and filtration may 
not reliably achieve more than 2.5-log or 3-log Cryptosporidium oocyst 
reduction under typical operating conditions. While membrane filtration 
technologies (ultrafiltration, nanofiltration), possibly following 
conventional treatment processes, appear to promise considerably 
greater reductions in Cryptosporidium densities, their widespread use 
for this purpose raises other concerns such as waste disposal of the 
concentrate, water wastage, potential failure of the membrane, and 
significant costs. Unless systems can feasibly achieve higher removal 
levels for Cryptosporidium by physical means, they would have to 
achieve this additional reduction by the use of disinfectants. However, 
uncertainties exist with respect to disinfection of Cryptosporidium. 
Current data suggests that chlorine and chlorine-based disinfectants 
are relatively ineffective in inactivating Cryptosporidium, and the 
Agency is not certain if alternative disinfectants, such as ozone, are 
more effective than chlorine to allow systems to comply with the 
removal/inactivation levels above.
    With this in mind, EPA is also considering two other treatment sub-
alternatives for Cryptosporidium, as follows: 

------------------------------------------------------------------------
                                                     Required treatment 
            No. cryptosporidium/100L                  level (percent)   
------------------------------------------------------------------------
<1...............................................  99 (2-log).          
1-9..............................................  99.9 (3-log).        
10-99............................................  99.99 (4-log).       
>99..............................................  99.999 (5-log).      
------------------------------------------------------------------------


------------------------------------------------------------------------
                                                     Required treatment 
            No. cryptosporidium/100L                  level (percent)   
------------------------------------------------------------------------
<10..............................................  99 (2-log).          
10-99............................................  99.9 (3-log).        
>99..............................................  99.99 (4-log).       
------------------------------------------------------------------------

    EPA requests comment on all treatment alternatives discussed above 
for Cryptosporidium.
    c. Alternative C. 99% (2-log) removal of Cryptosporidium. Under 
this alternative, EPA would require systems to achieve at least 99% (2-
log) removal of Cryptosporidium by filtration (with pretreatment) 
alone. This alternative is based on the premise that the 3-log removal/
inactivation requirement specified for Giardia is not economically or 
technologically feasible for Cryptosporidium, since laboratory data 
suggests that Cryptosporidium is considerably more resistant to 
disinfection than is Giardia. In addition, it may not be practical to 
remove more than two logs of Cryptosporidium consistently by 
clarification and filtration processes. EPA believes, however, that a 
two-log removal of Cryptosporidium is feasible using current 
conventional treatment methods of coagulation, sedimentation and 
filtration, as specified under the SWTR.
    Under this treatment option, EPA would continue to assess new field 
and laboratory data to control Cryptosporidium by physical removal and 
disinfection. If these data indicate that proportionally higher levels 
of Cryptosporidium removal/inactivation can be achieved at a reasonable 
cost, then EPA would revise the ESWTR accordingly as part of the long-
term ESWTR regulatory development. The Agency would also revise the 
SWTR Guidance Manual to suggest approaches for improving system design 
and operations for controlling Cryptosporidium. When sufficient human 
dose-response information for Cryptosporidium becomes available to 
allow calculation of drinking water health risks from this organism, 
EPA will consider a risk-based approach to establishing adequate 
treatment levels.
    EPA solicits comment on whether a higher minimum removal 
requirement than two logs should be specified for Cryptosporidium under 
this alternative. The Agency also requests comment on whether the 
removal requirement should be increased if treatment were to include 
disinfection.
    d. Alternative D. Specific disinfection treatment for viruses. The 
SWTR required systems to achieve a four-log reduction/ inactivation of 
viruses. This is to be achieved through a combination of filtration and 
disinfection or, for systems not required to filter their source 
waters, by disinfection alone. Viruses are of particular concern, given 
that one or several virus particles may be infectious (Regli et al., 
1991) and that several enteric viruses are associated with relatively 
high mortality rates (Bennett et al., 1987). Failure or impairment of 
filtration performance could allow substantial pathogen contamination 
of drinking water, particularly if the disinfection barrier following 
filtration is minimal.
    The SWTR considered Giardia to be a surrogate for viruses, and 
assumed that if viruses were present in the source water, treatment 
requirements adequate to reduce Giardia by three logs would also reduce 
viruses to safe levels. This assumption may not be appropriate if a 
system were to achieve a 3-log removal of Giardia by physical means and 
provide little disinfection inactivation. Viruses may be present in 
substantial numbers even in the absence of detectable Giardia cysts.
    Treatment designed to minimize Giardia may not be optimal for 
viruses. Viruses are substantially smaller than Giardia cysts or 
Cryptosporidium oocysts and may pass through certain filter media that 
will remove the larger protozoa. Therefore, use of data on Giardia, 
Cryptosporidium, or even coliform bacteria (intermediate in size 
between viruses and protozoa) in assessing treatment efficacy may not 
be adequate for virus control. Studies by Payment et al. (1991) showed 
that conventionally treated water meeting current Canadian microbial 
drinking water advisory levels still led to substantial illness in the 
studied population. These authors suggested that much of this illness 
could have resulted from viral infection.
    For the above reasons, particularly for strengthening the treatment 
barrier by disinfection, EPA is proposing to require that systems 
provide sufficient disinfection such that by disinfection alone it 
would achieve at least a 0.5-log inactivation of Giardia or, 
alternatively, a 4-log inactivation of viruses. This requirement would 
be independent of the level of physical removal, e.g., if filtration 
was able to remove three logs of Giardia, the system would still have 
to provide at least an additional 0.5-log inactivation of Giardia or 4-
log inactivation of viruses by disinfection. Therefore, this would mean 
that the system would provide 6 logs of virus removal/inactivation, 
assuming it is removing 2-logs of viruses by filtration alone. EPA 
would provide guidance to indicate the appropriate CT values to use 
with these two alternatives.
    The SWTR assumed that a 0.5-log inactivation of Giardia would 
result in a 4-log inactivation of viruses. This assumption was based on 
a study where the effect of free chlorine on the hepatitis A virus was 
examined (Sobsey, 1991). Subsequent investigations, however, have 
suggested that some viruses, such as the Norwalk agent, are 
substantially more resistant to disinfection by chlorine than is the 
hepatitis A agent. Additionally, use of disinfectants other than free 
chlorine to achieve the 0.5-log inactivation of Giardia may not yield a 
4-log inactivation of viruses. Therefore, a requirement to provide 
sufficient disinfection to inactivate 4 logs of viruses may be more 
conservative than the alternative requirement of providing sufficient 
disinfection to inactivate 0.5 logs of Giardia.
    Either of these two approaches could result in several additional 
logs of pathogen removal/inactivation for systems that practice 
conventional treatment. For example, where the system can remove by 
physical means at least 2-logs of viruses, the disinfection requirement 
would yield a total 6-log removal/inactivation of viruses (i.e, 2 logs 
by physical means and 4 logs by disinfection).
    e. Alternative E. No change to existing SWTR treatment requirements 
for Giardia and viruses. Under this alternative, the existing SWTR 
requirements for treatment for Giardia and viruses would not change. 
For Cryptosporidium control, EPA could either regulate this organism 
directly (e.g., Alternative C above) or make a finding that 
Cryptosporidium is adequately controlled by filtration and disinfection 
requirements in the existing SWTR. The Agency may choose this 
alternative to allow the Agency time to fully develop analyses of the 
ICR data and accumulate additional data on pathogen occurrence, 
treatment performance, and health effects, given the view that the 
current SWTR has not been in effect long enough to evaluate the 
projected improvements in drinking water quality and resulting public 
health benefits. EPA would consider additional regulatory alternatives 
while developing the long-term ESWTR, based on this new data. The 
Agency requests comment on this alternative, as well.

IV. State Implementation

    This section describes the regulations and other procedures and 
policies States would have to adopt, or have in place, to implement the 
rule proposed today. States must continue to meet all other conditions 
of primacy in 40 CFR Part 142.
    Section 1413 of the SDWA establishes requirements that a State must 
meet to maintain primary enforcement responsibility (primacy) for its 
public water systems. These include (1) adopting drinking water 
regulations that are no less stringent than Federal NPDWRs in effect 
under sections 1412(a) and 1412(b) of the Act, (2) adopting and 
implementing adequate procedures for enforcement, (3) keeping records 
and making reports available on its activities that EPA requires by 
regulation, (4) issuing variances and exemptions (if allowed by the 
State) under conditions no less stringent than allowed by sections 1415 
and 1416, and (5) adopting and being capable of implementing an 
adequate plan for the provision of safe drinking water under emergency 
situations.
    40 CFR Part 142 sets out the specific program implementation 
requirements for States to obtain primacy for the public water supply 
supervision (PWSS) program, as authorized under section 1413 of the 
Act. In addition to adopting the basic primacy requirements, States may 
be required to adopt special primacy provisions pertaining to a 
specific regulation. These regulation-specific provisions may be 
necessary where implementation of the NPDWR involves activities beyond 
those in the generic rule. States are required by 40 CFR 142.12 to 
include these regulation-specific provisions in an application for 
approval of their program revisions. These State primacy requirements 
would apply to the rule proposed today, along with the special primacy 
requirements discussed below.
    To implement today's proposed rule, States would be required to 
adopt revisions to Sec. 141.2, Definitions; Sec. 141.52, Maximum 
contaminant level goals for microbiological contaminants; Sec. 141.70, 
General requirements; Sec. 141.71, Criteria for avoiding filtration; 
and Sec. 141.74, Analytical and monitoring requirements.

A. Special State Primacy Requirements

    In addition to adopting drinking water regulations at least as 
stringent as the Federal regulations listed above, EPA would require 
that States adopt certain additional provisions related to this 
regulation to have their program revision application approved by EPA. 
Because this rule would provide considerable State latitude on 
implementation, today's rule would require a State to include, as part 
of its State program submission, its implementation policies and 
procedures. This information would advise the regulated community of 
State requirements and help EPA in its oversight of State programs. In 
concert with promulgating the interim ESWTR, EPA would revise the SWTR 
Guidance Manual (EPA, 1991). This guidance would assist States in 
developing appropriate criteria in the regulations they adopted.
    To ensure that the State program includes all the elements 
necessary for a complete enforcement program, today's notice proposes 
that to obtain EPA approval for implementing this rule, the State's 
application would be required to include the following:
    (1) Adoption of the promulgated ESWTR.
    (2) Description of the protocol the State will use to judge the 
adequacy of watershed protection programs for minimizing the potential 
for contamination by Giardia cysts, Cryptosporidium oocysts, and 
viruses in the source water. The SWTR required States to specify the 
methodology they would use to judge the adequacy of a watershed control 
program to control the presence of waterborne Giardia. This rule would 
add Cryptosporidium. The addition of Cryptosporidium is significant 
because it may prohibit or substantially limit certain watershed uses 
such as cattle farming and feedlots. The location of cattle feedlots on 
a watershed would require additional control measures.
    (3) Description of the criteria and methods the State will use for 
the conduct and review of sanitary surveys. If the State elects to 
allow non-State personnel to conduct the surveys, the State must 
specify the criteria for approval and oversight of these personnel and 
of the surveys.
    (4) Description of the procedures for determining the level of 
treatment required of systems to meet removal and/or inactivation 
requirements under the rule. If Alternative A described in Section IIIE 
above is promulgated, demonstration by the State that it has in place 
enforceable design and operating criteria for achieving the levels of 
Giardia removal and/or inactivation required. If either Alternative B 
or C described in Section IIIE above is promulgated, demonstration by 
the State that it has in place enforceable design and operating 
criteria for achieving the levels of Cryptosporidium removal and/or 
inactivation required. Compliance with the design and operating 
criteria would be judged on a system-by-system basis.

B. State Recordkeeping Requirements

    Changes to the existing recordkeeping requirements to implement the 
provisions proposed in this notice would require, under general 
recordkeeping requirements, States to maintain records on the level of 
treatment necessary to achieve the required levels of removal and/or 
inactivation of Giardia, Cryptosporidium and/or viruses. States would 
also be required to maintain a record of any decisions made as a result 
of sanitary surveys. These records must be kept for 40 years (as 
currently required by Sec. 142.14 for other State decision records) or 
until a subsequent determination is made, whichever is shorter. If the 
final rule requires systems to base level of treatment on source water 
pathogen densities, then the State must maintain record of these 
densities.

C. State Reporting Requirements

    Currently States must report to EPA information under 40 CFR 142.15 
regarding violations, variances and exemptions, enforcement actions and 
general operations of State public water supply programs. Today's rule 
would require States to provide additional information to EPA within 
the context of the existing special report requirements for the SWTR 
(Sec. 142.15(c)(1)) on microbial densities in the source water and the 
resulting required levels of treatment for each public water system 
supplied by a surface water source or by ground water under the direct 
influence of surface water.

V. Public Notice Language

    The SDWA (section 1414(c)) requires that notices of violation of 
the MCL or treatment requirement for a specific contaminant include 
EPA-specified language on the adverse health effects of that 
contaminant. Requirements for public notification are found in 40 CFR 
141.32. In this notice, EPA is proposing that the existing language for 
violating the treatment technique requirements in Subpart H of the 
SWTR, found in 40 CFR 141.32(e)(10), not be changed. This decision is 
based on EPA's belief that language is sufficiently broad to include 
the adverse health effects from Cryptosporidium exposure.

VI. Economic Analysis

A. Cost of Proposed Rule

    This proposed rule would result in treatment costs, monitoring 
costs, and State implementation costs. These costs are difficult to 
estimate because of uncertainty in the number of systems that would 
have to improve treatment and the extent of that improved treatment. 
This information would depend primarily on the results of future 
monitoring under the ICR. Under the ICR, systems using surface water 
and serving 10,000 people or more would determine raw water pathogen 
densities and, in some cases, the efficiency of treatment for reducing 
pathogen concentrations. Given the above uncertainties, the cost 
estimates can now only be addressed in the most general way, across a 
wide range of possibilities.
    With regard to treatment costs, if ICR results indicate that the 
existing SWTR ensures adequate levels of treatment for most systems, 
then minimal additional treatment costs would be necessary. Regardless 
of whether the SWTR is amended to require higher levels of treatment, 
at least some systems would be expected to upgrade existing levels of 
treatment based on EPA guidance and ICR monitoring results. Similarly, 
some systems might reduce existing levels of disinfection upon a 
finding that their source water is of better quality than expected. 
Also, some costs will be incurred by systems correcting for 
deficiencies identified through the sanitary survey requirement.
    If ICR monitoring indicates that many source waters contain 
considerably higher pathogen concentrations than anticipated under the 
SWTR, then substantial national treatment costs would result in 
mitigating the associated health risk. These costs could involve 
increasing disinfection contact time or dosage, switching to stronger 
disinfectants, or improving filtration efficiencies through upgrades or 
installation of new technologies.
    In estimating possible costs resulting from an ESWTR EPA assumed 
that (1) national Giardia density in source waters are represented by 
the survey results of LeChevallier et al. (1991a), (2) all systems are 
at least meeting the treatment requirements of the existing SWTR, (3) 
some systems, as indicated by the survey results of LeChevallier et al 
(1991), are providing higher levels of treatment than required by the 
SWTR, (4) systems would be required to provide sufficient treatment of 
their source water to achieve no greater than a 10-4 annual risk 
level for Giardia, based on the dose-response data and risk assessment 
methodology developed by Rose et al. (1991) and Grubbs et al. (1992), 
(5) additional Giardia reduction beyond the requirements of the SWTR to 
achieve the 10-4 risk level would be achieved solely by using 
chlorine as the disinfectant and providing additional disinfectant 
contact time (i.e., increasing the CT value by increasing the contact 
basin size), (6) when all ancillary construction costs including site-
specific factors are taken into account, the average total capital cost 
per system is twice the capital cost of increasing the size of the 
contact basin alone. Based on the assumptions of Rose et al. (1991) and 
Grubbs et al. (1992), EPA calculates that systems would need a Giardia 
removal/inactivation level of 3, 4, 5, or 6 logs for Giardia 
concentrations in the source water of <1 cysts/100 L, 1-9 cysts/100 L, 
10-99 cysts/100 L, and 100 cysts/100 L or greater, respectively.
    National cost estimates for systems to comply with an interim ESWTR 
as described above are provided in Table VI-1. As discussed in Section 
III.B of this preamble, depending upon the criteria that are 
promulgated under the interim ESWTR, EPA also intends to propose 
requirements for systems serving less than 10,000 people, under a long-
term ESWTR, to prevent any undue downside microbial risks that might 
otherwise result while systems of this size achieve compliance with the 
Stage 1 D/DBP rule. Therefore, Table VI-1 also includes cost estimates 
for systems serving less than 10,000 people, even though these costs 
are not attributed to the interim ESWTR.
    Table VI-1 presents the additional contact basin costs needed for 
twelve system size categories (population served); for each size 
category, the number and type of systems affected (filtered without 
softening or filtered with softening), the associated total capital 
costs, and the associated total annualized costs. In this calculation, 
operation and maintenance costs are assumed to be negligible since 
systems are already disinfecting and most of the additional 
inactivation could be achieved by additional disinfectant contact time. 
Details of this analysis and other assumptions are described in the 
Regulatory Impact Analysis for the ESWTR (EPA, 1994). Under this 
approach, EPA estimates that the capital and annualized costs 
nationwide for systems serving at least 10,000 people would be $3661 
million and $391 million, respectively. Using the same assumptions for 
systems serving fewer than 10,000 people would result in an additional 
$820 million capital costs and $114 million annualized costs 
nationwide, or a total for all system sizes of $4481 million in capital 
costs and $504 million in annualized costs.
    The 10-4 annual risk level target was used as an example; 
costs for achieving different acceptable risk levels, of course, will 
differ considerably. Although other treatment measures could be used to 
reduce Giardia levels, EPA believed that the national cost based on 
providing additional disinfectant contact time is probably 
representative, on average, of other modifications that systems might 
implement. The Agency chose this methodology for estimating costs 
because it was the most simple. Moreover, insufficient data prevents 
the Agency from predicting with any reliability the mix of different 
technologies systems would use to comply. EPA recognizes that in lieu 
of expanding contact basin size, some systems may achieve the required 
Giardia reductions through increased disinfectant dosages, improved 
sedimentation and filtration efficiencies, or use of a stronger 
disinfectant such as ozone. Smaller systems, especially those serving 
fewer than 1,000 people, might use cartridge filters, or membrane 
technology rather than additional contact time to achieve compliance 
with the long-term ESWTR and other drinking water regulations at lower 
cost. In addition, the costs for utilities to meet the D/DBP 
regulations (proposed elsewhere in today's Federal Register) are not 
necessarily additive with the costs for utilities to meet either the 
interim or long-term ESWTR. For example, systems installing membrane 
technology to comply with the D/DBP rule would also be expected through 
use of this technology to comply with the ESWTR. Use of technologies 
other than increasing contact basin time might be more feasible and 
less expensive for some systems, depending on site-specific factors 
(e.g., limited availability of land) and overall treatment objectives 
(e.g., meeting other regulatory requirements such as the D/DBR rule).
    EPA solicits comment on how many systems might use these 
alternative approaches for meeting ESWTR requirements and whether the 
use of such technologies would lead to substantially different cost 
estimates. EPA does not believe there are sufficient data to predict 
the costs for reducing Cryptosporidium to a desired risk level as has 
been done for Giardia. EPA solicits comment on what approaches might be 
taken for estimating national treatment costs for systems to provide 
different levels of Cryptosporidium removal depending on 
Cryptosporidium densities in the source water. Also, EPA requests 
comment on whether it is reasonable to assume that any treatment 
changes that are made to remove Cryptosporidium would also remove 
Giardia, thereby not duplicating costs for compliance.
    Table VI-2 indicates a range of estimated increases in household 
costs by system size category for systems needing to achieve an 
additional 0.5 log to 3 log reduction of Giardia to comply with the 
ESWTR option described above. By this analysis 35 percent of the 
systems would not be required to make any changes in treatment and 
would incur no costs. For the interim ESWTR, estimated increases in 
household costs for systems required to make changes in treatment would 
range from $11 to $49 per household per year in the smallest size 
category (serving a median population of 15,000 people) to $3.1 to $24 
per household per year in the largest size category (serving a median 
population of 1,550,000 people).
    If the analyzed criteria for the interim ESWTR were extended to 
smaller systems under the long-term ESWTR, and systems used additional 
disinfectant contact time to meet such criteria, increases in 
annualized household costs would range from $360 to $1100 per household 
per year in the smallest size category (serving a median population of 
57 people) to $27 to $85 per household per year in systems with a 
median population of 5,500. As stated above, EPA believes that smaller 
systems should be able to use a more economic treatment alternative 
than additional disinfectant contact time.
    EPA solicits comment on whether the system level costs to achieve 
the different log reductions indicated in Table VI-2 by disinfection, 
or other means, are reasonable and accurate.
    Table VI-3 indicates the estimated labor effort by the number of 
full time employees (FTEs), hours, and dollar costs for States to 
implement the interim ESWTR. If systems, rather than the State, were to 
fund some or all sanitary surveys, then State costs would be reduced 
accordingly. Further details of this analysis are available in the 
Regulatory Impact Analysis (EPA, 1994). 

                                          Table VI-1--Estimated National Contact Basin Costs for Enhanced SWTR                                          
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Cost estimates based on additional disinfectant contact basin size\1\           
                                                             -------------------------------------------------------------------------------------------
                                                               Number of affected systems      Total capital cost (M$)      Total annualized cost (M$)  
                                             Population per  -------------------------------------------------------------------------------------------
           System size category                  system            Filtering systems              Filtering systems              Filtering systems      
                                                             -------------------------------------------------------------------------------------------
                                                                W/out                         W/out                          W/out                      
                                                                soft     W/soft     Total     soft     W/soft      Total     soft     W/soft      Total 
--------------------------------------------------------------------------------------------------------------------------------------------------------
1.........................................  25-100                 493         8       501        22        0.5        23         4       0.09         4
2.........................................  101-500                454        13       467        42        1.4        43         8       0.3          8
3.........................................  501-1K                 415        47       462        86       12          98        16       2           18
4.........................................  1K-3.3K                586        61       647       200       24         224        25       3           28
5.........................................  3.3K-10K               627       104       731       360       72         432        45       9           54
6.........................................  10K-25K                291        67       358       330       94         424        34      10           44
7.........................................  25K-50K                167        42       209       340      110         450        36      12           47
8.........................................  50K-75K                 77        24       101       230       92         322        24      10           34
9.........................................  75K-100K                63         7        70       250       37         287        26       4           30
10........................................  100K-500K               88        24       112       620      230         850        67      25           92
11........................................  500K-1M                 22         5        27       600      170         770        64      18           83
12........................................  1M+                      9         1        10       460       97         557        50      11           60
                                           -------------------------------------------------------------------------------------------------------------
Totals:                                                                                                                                                 
      Interim Rule (Systems > 10K)........  ................       716       170       887      2830      831        3661       302      88          391
      Long-Term Rule (All Systems)........  ................     3,290       404     3,694     3,540      941       4,481       401     103         504 
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:                                                                                                                                                  
\1\Cost estimates were developed on the basis of the following assumptions: 1) 35 percent of surface water systems currently meet ESWTR inactivation    
  requirements (based on LeChevallier et al., 1991); 2) the amount of additional inactivation required by systems that do not currently meet ESWTR      
  requirements is based on the distribution of source water Giardia concentrations in the LeChevallier data; and 3) the additional basin volume is based
  upon CT requirements of the SWTR guidance document with: pH = 8 (non-softening) or 9 (softening), t10 : ttheoretical = 0.7, temperature = 5  deg.C,   
  and C12 residual = 1 mg/l.                                                                                                                            


  Table VI-2--Estimated Increases in Annual Houshold Costs for Systems Expanding Contact Basin Size to Meet an  
                                                Enhanced SWTR\2\                                                
----------------------------------------------------------------------------------------------------------------
                                                                  Total household costs, $/hh/yr\3\             
                                                     -----------------------------------------------------------
               Cat. #                   Median pop.            Filter\4\               Filter and Soften\4\     
                                                     -----------------------------------------------------------
                                                         Min     Avg\1\     Max       Min     Avg\1\      Max   
----------------------------------------------------------------------------------------------------------------
1...................................              57     360       420        960     430       500        1,100
2...................................             225     170       200        450     200       240          540
3...................................             750      88       120        310     110       150          350
4...................................           1,910      36        52        110      43        59          130
5...................................           5,500      27        28         67      30        34           85
6...................................          15,000      11        15         40      13        19           49
7...................................          35,000       7.9      12         30      10        15           39
8...................................          60,000       6.6      10         26       8.8      13           34
9...................................          88,100       6.1       8.8       24       7.5      12           32
10..................................         175,000       5.1       8.5       24       6.6      11           33
11..................................         730,000       3.5       6.7       20       4.7       9.1         27
12..................................       1,550,000       3.1       6.0       18       4.2       8.2        24 
----------------------------------------------------------------------------------------------------------------
Notes:                                                                                                          
\1\Costs assume that 35 percent of systems currently meet ESWTR requirements (LeChevallier et al., 1991) and    
  therefore do not require contact basin modifications.                                                         
\2\Assumes Giardia and level of treatment distributions per LeChevallier et al, 1991 are nationally             
  representative of arithmetic averages, and that systems under ESWTR are required to provide additional        
  disinfection inactivation to meet a less than 1/10,000 annual infection rate at the first customer calculated 
  according to the Giardia infectivity dose response curve of Rose et al. (1991).                               
\3\Household costs represent costs for affected systems. Minimum costs are based on costs for systems requiring 
  additional 0.5 log inactivation while maximum costs are based on requiring an additional 3-log inactivation.  
  Average costs are based on distribution of costs for achieving different inactivations based on data by       
  LeChevallier et al. (1991).                                                                                   
\4\Contact basin size dependent upon chlorine residual, pH and temperature. Contact basin costs will increase if
  chlorine residual or temperature decrease or if pH increases. For non-softening systems (``Filter'' and       
  ``Unfilt'') pH=8, temperature=5  deg.C, and chlorine residual=1 mg/L. For softening systems (``Soften''),     
  pH=9, temperature=5  deg.C, and chlorine residual=1 mg/L.                                                     


              Table VI-3.--Interim Enhanced Surface Water Treatment Rule State Program Costs Model              
----------------------------------------------------------------------------------------------------------------
                                                                             National burden                    
           Variable                  Default assumptions                -------------------------      Cost     
                                                                           In FTEs    In hours                  
----------------------------------------------------------------------------------------------------------------
Regulation Adoption and         0.5 FTE per State.............        1        28.0       47,040      $1,540,000
 Program Development.                                                                                           
Review Plans and Specs........  10 days/large system..........      112    \1\N/A         \1\N/A          \1\N/A
Log Removal Determination.....  3 days per surface water             19        19.0       31,958      1,046,250 
                                 system.                                                                        
                               ---------------------------------------------------------------------------------
      Subtotal (x)............  ..............................  .......        47         78,998       2,586,250
Staff Training (Rule Specific)  10 days per technical FTE=f(x)        0         2.1        3,591         117,557
Sanitary Surveys\3\...........  5 days/lg. sys./survey; 2 days/      79        78.7      132,147      4,326,250 
                                 sm. sys./survey.                                                               
                               =================================================================================
      Total...................  ..............................  .......       128        214,736       7,030,057
Average Annual Cost over 3.5    ..............................  .......        37         61,353      2,008,588 
 years\2\.                                                                                                      
----------------------------------------------------------------------------------------------------------------
\1\Costs for reviewing plans and specifications for the ESWTR are counted as a joint activity undertaken with   
  the same step of implementing the Stage 1 DBP Rule and are included in the DBP Rule RIA.                      
\2\Total cost and burden are divided by 3.5 years, the time between promulgation of this rule and the final     
  ESWTR.                                                                                                        
\3\Recordkeeping burden is assumed to equal approximately 2% of the burden shown (i.e. approximately 1.6 FTEs,  
  2,640 hours, $86,000).                                                                                        

B. Benefits of Proposed Rule

    The level of reduction of waterborne illness resulting from 
implementation of this rule will largely depend on the particular 
option(s) promulgated. Even if EPA could predict the most suitable 
option(s), the Agency cannot yet predict the number of illnesses 
avoided until more data become available. EPA anticipates that much of 
such data, particularly on national pathogen occurrence and existing 
treatment levels, will become available under the forthcoming ICR.
    With the limited available data, EPA has used a disinfection 
byproducts risk assessment model (DBPRAM) to estimate potential risks 
from Giardia that might result from systems complying with different 
DBP standards both with the existing SWTR and an ESWTR (Grubbs et al 
1992; Regli et al 1993; Cromwell et al 1992). In this analysis, EPA 
assumed that the ESWTR would require systems to remove/inactivate 
Giardia by 3, 4, 5, or 6 logs if the Giardia concentrations in the 
source water were <1 cysts/100 L, 1-9 cysts/100 L, 10-99 cysts/100 L, 
and 100 cysts/100 L or more, respectively. This assumption is 
consistent with current EPA guidance (EPA, 1991a).
    Because of the limited data, EPA used the DBPRAM only for the 
category of surface water systems that serve at least 10,000 people and 
practice coagulation, sedimentation, and filtration, but do not soften 
the water. Collectively this group of systems provides water to about 
103 million people.
    EPA assumed as part of the modeling effort that (1) Giardia 
densities in source waters in the U.S. are represented by the survey 
data of LeChevallier et al. (1991a), (2) systems are using, or will 
use, the least expensive technologies to comply with the SWTR and 
existing TTHM standard, and (3) systems comply only minimally with both 
the SWTR (i.e., provide a 3-log removal/inactivation of Giardia cysts 
and maintain a disinfectant residual throughout the distribution 
system) and the existing TTHM standard. Using these assumptions, the 
model predicts that, without revising the SWTR, several hundred 
thousand people would become infected by Giardia each year. These 
predicted risks may be significantly overstated because many systems 
currently appear to provide more treatment than is minimally required 
under the SWTR (LeChevallier et al., 1991b). Also, concentrations of 
Giardia cysts in source waters in the U.S. may be significantly less 
than those indicated by the survey results of LeChevallier et al. 
(1991a), which did not cover all geographical locations.
    The DBPRAM also predicted that, in the absence of any revision to 
the SWTR, as the hypothetical MCL for DBPs decreases (i.e., either for 
TTHMs or the sum of five haloacetic acids), the incidence of Giardia 
infection significantly increases. One reason for this result is that 
lower MCLs would lead systems to use more efficient precursor removal 
technologies, resulting in a lower disinfectant demand in the water. 
Therefore, since less disinfectant is necessary, a lower CT value may 
result at the first customer. Without the removal of DBP precursors (or 
associated disinfectant demand), systems would need to maintain a 
higher CT value at the first customer to maintain a disinfectant 
residual throughout the distribution system.
    A second reason why the predicted incidence of Giardia infection 
increases as the MCL for DBPs is lowered is that the model assumes that 
many systems would switch to chloramine as a residual disinfectant, or 
to ozone followed by chloramine, to limit the formation of chlorinated 
DBPs. Chloramine is a weaker disinfectant than chlorine and 
consequently would result in less Giardia inactivation. Similarly, the 
model also assumes that if a system were to switch to ozone for primary 
disinfection, followed by chloramine, the system would provide only 
enough disinfection to inactivate 0.5 logs of Giardia to minimally meet 
the SWTR (assuming that 2.5 log of Giardia removal is achieved by 
physical means). This latter assumption may underestimate the actual 
level of Giardia inactivation that a system would likely provide, since 
for a relatively small increase in cost compared to that for ozone 
installation, the system could achieve (by increasing the ozone dose or 
contact time) a significantly greater level of inactivation than the 3-
log reduction specified by the SWTR for Giardia. 
    The DBPRAM also predicts that under more stringent DBP standards, 
if such systems were to only minimally meet the SWTR, the incidence of 
waterborne disease outbreaks would significantly increase in systems 
with the worst quality source waters (but apparently not in those with 
good quality source waters) (Grubbs et al., 1992; Regli et al., 1993). 
In its modeling effort, EPA defined waterborne disease outbreaks 
(epidemic disease) as one in which at least 1% of the population became 
infected (conservatively used as an indicator for illness) within a 30-
day period; this definition was used because EPA believes that at 
incidence lower than 1% health authorities are generally not aware that 
an outbreak is in progress, unless the disease is typically very 
debilitating or life-threatening. According to Harrington et al. 
(1985), the total cost of disease avoidance behavior, such as boiling 
or purchase of bottled water by the entire community, during an 
outbreak far exceeds the total cost of treating the illness.
    The DBPRAM predicts that ESWTR compliance, as described above, 
would result in no more than a few hundred infections caused by 
waterborne Giardia per year per 100 million people. This is several 
hundred thousand cases fewer than predicted in the absence of an ESWTR. 
In the absence of more data and for the purpose of simplicity, the 
model assumes that systems would use the arithmetic mean (based on 
LeChevallier et al., 1991a) to calculate pathogen densities, and use 
the coldest water temperature and maximum flow rate (design rate) to 
determine disinfection conditions at which plants would operate. Use of 
the arithmetic mean may underestimate the predicted risk since values 
above the mean may result in a greater number of infections than values 
below the mean.
    In contrast, using the design flow rate throughout the year for 
model predictions overestimates the predicted risk, because the flow 
rate should be significantly less during colder weather, which would 
result in longer contact times and greater CT values, and therefore 
greater inactivation of Giardia than if the system operated under 
design flow conditions during this period. In addition, use of the 
coldest water temperature throughout the year for model predictions 
also overestimates the predicted risk, because disinfectants are more 
effective at warmer water temperatures for a given CT. In the absence 
of more data, EPA cannot determine whether the model assumptions, 
collectively, may significantly bias the model predictions. EPA 
solicits comment on this issue and requests suggestions on how EPA can 
improve the assumptions in the model, based upon data collected under 
the ICR (59 FR 6332; proposed February 10, 1994).
    The model also predicts that if systems complied with an ESWTR, no 
waterborne disease outbreaks (as defined above) attributed to Giardia 
would occur. Since Giardia is more resistant to disinfection than most 
other pathogens (Cryptosporidium being a notable exception), EPA 
assumes that the incidence of waterborne disease caused by other 
pathogens would also be substantially reduced.
    The disease, giardiasis, causes a gastrointestinal disorder that 
may be mild or severe and incapacitating, and that generally lasts from 
one to four weeks. Although mortality is very low (0.0001%), some 
patients, including otherwise healthy individuals, require 
hospitalization (about 4600 annually) (Bennett et al., 1987; Addiss and 
Lengerich, 1994). An individual with giardiasis typically has one or 
more of the following symptoms: diarrhea, cramps, abdominal distress, 
flatulence, fatigue, vomiting, chills, fever, and marked weight loss. 
In one study of 105 stool-positive cases of travelers returning to the 
U.S., 39 percent had mild symptoms, 41 percent had moderate symptoms, 
6.7 percent had incapacitating or severe symptoms, and 13.3 percent had 
no symptoms (Wolfe, 1990). All age groups are affected. The average 
time between infection and the onset of disease is about two weeks, 
although this may vary considerably. Chronic cases that persist for 
months or longer are not uncommon.
    In the original SWTR Regulatory Impact Analysis (EPA, 1989a), the 
estimated economic cost associated with waterborne giardiasis was based 
on a study of costs incurred during an outbreak of waterborne 
giardiasis in 1983 that occurred in Scranton, Pennsylvania (Harrington, 
et al., 1985). In this study, the investigators estimated that the 
medical cost and the cost of time lost from work associated with the 
outbreak was in the range of $1245 to $1878 per case (1984 dollars). 
The lower cost values the time loss for homemakers, retired persons, 
and unemployed persons as zero, while the higher cost values the time 
loss for these people at the average wage rate.
    The above estimate was based on the results of a survey of 370 
people who had ``confirmed'' cases of giardiasis, i.e., a positive 
stool sample. EPA assumed in the analysis that the costs associated 
with confirmed cases are representative of the costs associated with 
those who had symptoms of giardiasis, but where no stool sample was 
examined, since medical costs (minus the cost for a stool specimen 
examination) and cost for time lost from work should be similar when 
symptoms are similar.
    The $1245-$1878 estimate above does not take into account 
fatalities associated with waterborne disease. According to Bennett et 
al. (1987), about 0.1 percent of cases of waterborne disease are fatal. 
Although these investigators estimate that the mortality rate for 
giardiasis is much lower than 0.1 percent, EPA believes that control of 
Giardia will also control other waterborne disease agents that have a 
higher mortality rate than Giardia. Therefore, by omitting the risk of 
mortality associated with waterborne disease, EPA's analysis may 
represent a significant underestimate of the benefits. In addition, 
EPA's analysis did not consider benefits associated with avoiding the 
economic and psychological costs to the affected community (including 
businesses and government) associated with a waterborne disease 
outbreak, nor did it consider the benefits of additional public 
confidence in an enhanced water supply. These benefits were not 
considered in the analysis because of the difficulty of quantifying 
them.
    Adjusting the $1878/case value for inflation (through 1993), and 
including a factor for willingness-to-pay, EPA estimates the benefit 
would be $3,000 per Giardia infection avoided. Using this estimate, the 
400,000 to 500,000 Giardia infections per year that could be avoided in 
large surface water systems would have an economic value of $1.2 to 
$1.5 billion per year. This suggests that the benefit nationwide of 
avoiding Giardia infections in large systems is as much as three or 
four times greater than the estimated $391 million national cost per 
year to provide additional disinfectant contact time.
    At a household level, the Interim ESWTR would impose costs ranging 
from $11- $49/household/year in systems serving 15,000 people to $3-
$24/household/year in systems serving 1,550,000. Household costs are a 
useful guide for examining cost-benefit tradeoffs, because they are 
easier to understand in assessing the public's willingness to pay for a 
more stringent rule. EPA does not believe that the household costs 
predicted by this analysis represents an unreasonable premium for the 
systems affected by the Interim ESWTR, considering the nature of 
microbial risk.
    There are at least three approaches for examining the tradeoff 
between costs and benefits. One approach is to determine the cost of 
the ESWTR alone. In a second approach, EPA could use the combined cost 
of the SWTR and ESWTR, since customers of many water systems are 
already paying, or will soon be paying, an extra premium for microbial 
protection as a result of the original SWTR. If this second approach is 
used (the most expensive estimate of ESWTR cost), and if the cost of 
the original SWTR is adjusted for inflation and factored into the above 
analysis, the overall ratio of benefits to costs would still be about a 
break-even proposition. Household costs would be significantly higher 
for previously unfiltered systems and modestly higher for previously 
filtered systems. In the third approach, EPA could assume that a large 
share of the cost of an ESWTR should be borne by the DBP rule, since 
the treatment changes needed to meet more stringent DBP regulations may 
increase the pathogen risk that the ESWTR must address.
    The accounting difficulty of sorting between microbial and DBP 
costs will become even more complicated later in developing the Long-
Term ESWTR, which will cover small systems. Household costs for 
providing additional disinfectant contact time in small systems are 
significantly greater than those for the larger systems. However, it is 
not clear that small systems will choose to meet the Long-Term ESWTR by 
increasing the contact time. Such options as small scale membrane 
treatment systems may provide a more economical means of meeting both 
microbial and DBP treatment requirements simultaneously. In that case, 
the microbial and DBP-related control costs would be truly 
indistinguishable from each other.
    A similar analysis to the one described above for Giardia is not 
yet feasible for Cryptosporidium because of much greater data 
deficiencies. The analysis of national benefits for the different ESWTR 
options must remain highly speculative, even for Giardia, until more 
data become available. EPA intends to develop a more complete cost and 
benefit analysis for the different ESWTR options based on data 
generated under the ICR and complementary research. This analysis would 
examine the costs of the various treatment options indicated in Section 
IIIE above, using various statistical approaches to calculate pathogen 
densities (e.g., mean value versus 90th percentile value), acceptable 
risk levels, pathogen infectivities, and various assumptions about the 
analytical methods (e.g., cyst/oocyst viability, percent recovery) and 
include a broader discussion of the benefits. EPA intends to present 
such analysis in a Notice of Availability in the Federal Register by 
November 1995. This Notice will indicate the basis for EPA's preferred 
ESWTR option(s) and solicit comment on the appropriateness for 
promulgating this option(s) as part of the interim ESWTR. EPA solicits 
comment on approaches that can be used for this analysis.

VII. Other Statutory Requirements

A. Executive Order 12866

    Under Executive Order 12866 (58 FR 51735 (October 4, 1993)), the 
Agency must determine whether the regulatory action is ``significant'' 
and therefore subject to OMB review and the requirements of the 
Executive Order. The Order defines ``significant regulatory action'' as 
one that is likely to result in a rule that may:
    (1) Have an annual effect on the economy of $100 million or more or 
adversely affect in a material way the economy, a sector of the 
economy, productivity, competition, jobs, the environment, public 
health or safety, or State, local, or tribal governments or 
communities;
    (2) Create a serious inconsistency or otherwise interfere with an 
action taken or planned by another agency;
    (3) Materially alter the budgetary impact of entitlement, grants, 
user fees, or loan programs or the rights and obligations of recipients 
thereof; or
    (4) Raise novel legal or policy issues arising out of legal 
mandates, the President's priorities, or the principles set forth in 
the Executive Order.
    Pursuant to the terms of Executive Order 12866, it has been 
determined that this rule is a ``significant regulatory action'' 
because it will have an annual effect on the economy of $100 million or 
more. As such, this action was submitted to OMB for review. Changes 
made in response to OMB suggestions or recommendations will be 
documented in the public record.

B. Regulatory Flexibility Act

    The Regulatory Flexibility Act, 5 U.S.C. 602 et seq., requires EPA 
to explicitly consider the effect of proposed regulation on small 
entities. By policy, EPA has decided to consider regulatory 
alternatives if there is any economic impact on any number of small 
entities. The Small Business Administration defines a ``small water 
utility'' as one which serves fewer than 3,300 people.
    The proposed rule is consistent with the objectives of the 
Regulatory Flexibility Act because it will not have any economic impact 
on any small entities. Except for the sanitary survey requirement, 
which EPA believes will be conducted by States, the rule would only 
apply to systems serving at least 10,000 people. Therefore, the Agency 
believes that this notice would have no adverse effect on any number of 
small entities.

C. Paperwork Reduction Act

    The information collection requirements in this proposed rule have 
been submitted for approval to the Office of Management and Budget 
(OMB) under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. An 
Information Collection Request document has been prepared by EPA (ICR 
No. 270.32) and a copy may be obtained from Sandy Farmer, Information 
Policy Branch (MC:2136), EPA, 401 M Street, SW, Washington, DC 20460, 
or by calling (202) 260-2740.
    The reporting and recordkeeping burden for this proposed collection 
of information will be phased in starting in 1997. The specific burden 
anticipated for each category of respondent, by year, is shown below:

1997

Public Water Systems--monitoring and reporting
    Hours per respondent: 0
    Total hours: 0
Public Water Systems--recordkeeping
    Hours per respondent: 0
    Total hours: 0
State Program Costs--reporting
    Hours per respondent: 1,599
    Total hours: 89,518
State Program Costs--recordkeeping
    Hours per respondent: 16
    Total hours: 904

1998

Public Water Systems--monitoring and reporting
    Hours per respondent: 0
    Total hours: 0
Public Water Systems--recordkeeping
    Hours per respondent: 0
    Total hours: 0
State Program Costs--reporting
    Hours per respondent: 1,149
    Total hours: 64,337
State Program Costs--recordkeeping
    Hours per respondent: 12
    Total hours: 650

1999

Public Water Systems--monitoring and reporting
    Hours per respondent: 0
    Total hours: 0
Public Water Systems--recordkeeping
    Hours per respondent: 0
    Total hours: 0
State Program Costs--reporting
    Hours per respondent: 699
    Total hours: 39,157
State Program Costs--recordkeeping
    Hours per respondent: 7
    Total hours: 396
    Send comments regarding the burden estimate or any other aspect of 
this collection of information, including suggestions for reducing this 
burden, to Chief, Information Policy Branch (MC:2136), EPA, 401 M 
Street, SW, Washington, DC 20460; and to the Office of Information and 
Regulatory Affairs, OPM, Washington, DC 20503, marked ``Attention: Desk 
Officer for EPA.'' The final rule will respond to any OMB or public 
comments on the information collection requirements contained in this 
proposal.

D. Science Advisory Board, National Drinking Water Advisory Council, 
and Secretary of Health and Human Services

    In accordance with section 1412 (d) and (e) of the SDWA, EPA 
consulted with the Science Advisory Board, National Drinking Water 
Advisory Council, and Secretary of Health and Human Services and 
requested their comments in developing this rule.

E. Consultation With State, Local, and Tribal Governments

    Two Executive Orders (E.O. 12875, Enhancing Intergovernmental 
Partnerships, and E.O. 12866, Regulatory Planning and Review) 
explicitly require Federal agencies to consult with State, local, and 
tribal entities in the development of rules and policies that will 
affect them, and to document what they did, the issues that were 
raised, and how the issues were addressed.
    As described in Section I of today's rule, SDWA Section 1412 
requires EPA to promulgate NPDWRs, to review each NPDWR every three 
years, and to revise it as appropriate. In 1989, EPA issued the SWTR, 
in accordance with SDWA Section 1412(b)(7)(C). That rule went into 
effect in 1991. That rule has since been reviewed and is being 
reproposed today.
    This proposal, which pertains only to systems serving more than 
10,000 persons, contains several options for final promulgation. 
Depending on the option selected, PWSs with poorer quality source 
waters may need to remove microbiological contaminants above levels 
currently required under the SWTR. PWSs may also be required to treat 
for Cryptosporidium. There are currently insufficient data to develop 
an annual cost estimate of compliance with this rule.
    In 1992, EPA considered entering into a negotiated rulemaking on a 
related Disinfectant/Disinfection By-Products rule primarily because no 
clear path for addressing all the major issues associated with the D/
DBP rule was apparent. EPA hired a facilitator to explore this option 
with external stakeholders and, in November 1992, decided to proceed 
with the negotiation. The 18 negotiators, including EPA, met from 
November 1992 until June 1993 at which time agreement was reached on 
the content of the D/DBP proposed rule. That rule is proposed elsewhere 
in today's Federal Register. During the negotiations, the negotiators 
identified the possible need for a companion rule on surface water 
treatment. The purpose of the companion rule was to guard against the 
possibility of increasing microbial risk while controlling for 
disinfectant/disinfection byproduct risk. The contents of today's 
proposed regulatory and preamble language for enhanced surface water 
treatment have been agreed to by the 17 negotiators who remained at the 
table through June 1993. A summary of those negotiations is contained 
in Section II.
    The negotiators included persons representing State and local 
governments. At the table were:
    (1) Association of State Drinking Water Administrators, a group 
representing state government officials responsible for implementing 
the regulations,
    (2) Association of State and Territorial Health Officials, a group 
representing statewide public health interests and the need to balance 
spending on a variety of health priorities,
    (3) National Association of Regulated Utilities Commissioners, a 
group representing funding concerns at the state level,
    (4) National Association of County Health Officials, a group 
representing local government general public health interests,
    (5) National League of Cities, a group representing local elected 
and appointed officials responsible for balancing spending needs across 
all government services,
    (6) National Association of State Utility Consumer Advocates, a 
group representing consumer interests at the state level, and
    (7) National Consumer Law Center, a group representing consumer 
interests at the local level.
    In addition, several associations representing public municipal and 
investor-owned water systems also served on the committee.
    As part of the negotiation process, each of these representatives 
was responsible for obtaining endorsement from their respective 
organization on the positions they took at the negotiations and on the 
final signed agreement. During the negotiations, the group heard from 
many other parties who attended the public negotiations and were 
invited to express their views. As is true with any negotiation, all 
sides presented initial positions which were ultimately modified to 
obtain consensus from all sides. However, all parties mentioned above 
signed the final agreement on behalf of their associations. This 
agreement reflected basic consensus that the possible cost of the rule 
would be offset by its public health benefits and its promotion of 
responsible drinking water treatment practices.
    The only original negotiator who did not sign the agreement left 
the negotiations in March 1993. That negotiator represented the 
National Rural Water Association (NRWA), a group representing primarily 
small public and private water systems. At the time that group left the 
negotiations, they were objecting to the cost of the D/DBP rule, which 
applies to all system sizes. Except for a sanitary survey requirement 
that EPA believes will be conducted by States, the interim ESWTR would 
only apply to systems serving greater than 10,000 persons and thus does 
not affect NRWA members. Earlier in the negotiations, NRWA accepted the 
position that any control of disinfectants and disinfection by-products 
should not come at the expense of decreased protection from microbial 
contamination. The NRWA position that small systems should meet a less 
stringent trihalomethane standard than larger systems was rejected by 
the remaining negotiators, several of whom also represent small water 
systems.
    The contents of today's proposed rule has been available to the 
public for several months as part of the regulatory negotiation 
signature process. EPA has briefed numerous groups, including 
government organizations, on its contents. The Agency has received 
several letters from public water systems objecting to the cost of the 
proposed rule and questioning its potential health benefit. These 
letters are contained in the public docket supporting today's rule. The 
Agency recognizes that many persons are concerned whether the proposed 
rule is warranted. The technical issues are complex. The process needed 
to develop a common level of understanding among the negotiators as to 
what was known and unknown and what are reasonable estimates of 
potential costs and benefits was time-consuming. It is unreasonable to 
expect persons not at the negotiating table to have that same level of 
understanding and to all share the same view. However, the discussions 
throughout the negotiated rulemaking process were informed by a broad 
spectrum of opinions. The Agency believes this consensus proposal is 
not only the preferred approach but one which will generate informed 
debate and comment.

VIII. Request for Public Comment

    EPA solicited public comments on specific issues earlier in the 
preamble and welcomes comments on any other issue the public may wish 
to address. For ease in referring to requests for comments we are 
listing them below. In addition, at the end of this section, the Agency 
is requesting comment on other issues not addressed earlier in the 
preamble.
     (III.C) Rationale for setting MCLG of zero and a treatment 
technique for Cryptosporidium
     (III.D.1) Ground water under the direct influence of 
surface water

--Including Cryptosporidium in rule language in definition of ground 
water under the direct influence of surface water
--Revising guidance defining ground water under the influence of 
surface water
--Most appropriate procedure for determining credits for removal/
inactivation and treatment requirements for systems using ground waters 
under the direct influence of surface water

     (III.D.3) Sanitary surveys

--Prerequisites for individuals performing sanitary survey (academic 
degree, etc.)
--Revisions needed in SWTR Guidance Manual for conducting sanitary 
survey for filtered systems and for evaluating vulnerability to 
Cryptosporidium
--Frequency of sanitary surveys (three vs. five years)

     (III.D.4) Possible supplemental requirements

--Whether to publish national rule to require systems to cover finished 
water reservoirs and storage tanks, or whether this should be left to 
State discretion. What would the cost be for such a rule, and what 
waiver provisions would be appropriate.
--Whether EPA should require States and/or systems to have a cross- 
connection control program; what specific criteria, if any, should be 
included therein; how often such a program should be evaluated; under 
what conditions a waiver could be granted; and whether only those 
connections identified as a cross-connection by the public water system 
or the State should be subject to a cross-connection program.
--Identification of measures other than cross-connection control 
program to prevent the contamination of drinking water already in the 
distribution system (e.g., minimum pressure requirements in the 
distribution system).
--Whether to require systems to notify the State for persistent 
turbidity levels above the performance standard (but not in violation 
of this standard)

     (III.E) Alternative Treatment Requirements
    1. Options for defining pathogen densities

--Appropriateness of requiring systems whose population served grows to 
over 10,000 to perform ICR monitoring.
--Appropriateness of the four approaches for calculating pathogen 
densities, and whether approach selected should be based on number of 
pathogen samples collected

    2. Treatment alternative for controlling pathogens

--Appropriateness and magnitude of specific acceptable risk levels for 
microbes
--Which treatment approach(es) is most appropriate
--Identification of approaches for achieving levels of pathogen removal 
greater than 2.5 logs by physical means
--Utility of extrapolating CT values in SWTR Guidance Manual to predict 
the effect on pathogens of higher levels of disinfection
--Appropriateness of two treatment alternatives, with possible 
variations, for removal of Giardia 
--Appropriateness of indicated treatment alternatives for 
Cryptosporidium 
--Feasibility of removing more than two logs of Cryptosporidium (with 
and without disinfection being considered). -
Appropriateness of not
--Changing treatment specifications in SWTR

     (VI) Economic Analysis

--What approaches are reasonable for estimating the national treatment 
costs of requiring systems to remove a level of Cryptosporidium that 
would depend on Cryptosporidium densities in the source water
--Are the system level costs in Table VI-2 for increasing the 
disinfectant contact time reasonable and accurate
--The number of systems that might use control measures other than 
increasing contact basin time requirements and whether the use of such 
technologies would lead to substantially different cost estimates
--Assumption in estimating economic impact that treatment changes to 
control Cryptosporidium will also control Giardia 
--Soundness of assumptions made in disinfection byproducts risk 
assessment model (DBPRAM) used to estimate potential risks from Giardia 
that might result from systems complying with different DBP standards 
both with the existing SWTR and an ESWTR, and how these assumptions 
could be improved

Other Issues

     How should EPA decide, in developing a forthcoming Notice 
of Availability, what treatment approach(es) is most suitable for 
additional public comment?
     What criteria, if any, should the ESWTR include to ensure 
that systems optimize treatment plant performance?
     Should any turbidity performance criteria in the SWTR be 
modified? For example, should the ESWTR require systems to base 
compliance with the turbidity standards on monitoring the turbidity at 
the effluent of each filter separately, in lieu of (or in addition to) 
the confluence of all filters? Should any performance standard value be 
changed?
     To what extent should the ESWTR address the issue of 
recycling filter backwash, given its potential for increasing the 
densities of Giardia and Cryptosporidium on the filter?
     Should the ESWTR define minimum certification criteria for 
surface water treatment plant operators? Currently, the SWTR 
(Sec. 141.70) requires such systems to be operated by ``qualified 
personnel who meet the requirements specified by the State.''
     Should the ESWTR include a performance standard(s) for 
particle removal?
     Under what conditions could systems be allowed different 
log removal credits than is currently recommended in the SWTR Guidance 
Manual?

IX. Instructions to Commenters

    To ensure that EPA can read, understand and therefore properly 
respond to comments, the Agency would prefer that commenters type or 
print comments in ink, and cite, where possible, the paragraph(s) in 
this proposed regulation (e.g. 141.76(b)) to which each comment refers. 
Commenters should use a separate paragraph for each method or issue 
discussed.

X. References

Addiss, DG, and EJ Lengerich (1994). Hypokalemic myopathy induced by 
Giardia lamblia. N. Engl. J. Med. 330(1):66.
AWWA. American Water Works Association (1992). Jackson County Oregon 
cryptosporidiosis outbreaks: January-June 1992. Summary, Expert 
Meeting, August 3, 4, 1992.
AWWA. American Water Works Association (1993). Officers & Committee 
Directory. AWWA, Denver.
Bailey SW, and EC Lippy (1978). Should all finished water reservoirs 
be covered. Public Works for April 1978. P. 66-70.
Bennett JV, SD Holmberg, MF Rogers and SL Solomon (1987). Infectious 
and parasitic diseases. Am J Prev Med 3: 102-114. In: RW Amler and 
HB Dull (eds), Closing the gap: the burden of unnecessary illness. 
Oxford University Press, Oxford.
Berger PS, S Regli and L Almodovar (1992). Cryptosporidium control 
in drinking water. Am Water Works Assoc Proceedings, 1992 Annual 
Conf, Mgmt and Regs, pp 845-864. American Water Works Association, 
Denver.
Casemore DP and FB Jackson (1984). Hypothesis: cryptosporidiosis in 
human beings is not primarily a zoonosis. J Infect 9: 153-156.
Casemore DP (1990). Epidemiological aspects of human 
cryptosporidiosis. Epid Infec 104: 1-28.
CDC. Centers for Disease Control (1982). Cryptosporidiosis: 
assessment of chemotherapy of males with acquired immune deficiency 
syndrome (AIDS). Morbidity and Mortality Weekly Report 31: 589-592.
Clancy JL (1993). Interpretation of microscopic particulate analysis 
data--a water quality approach. Water Quality Technology Conference 
Proceedings, 1992, II: 1831-1844. American Water Works Association, 
Denver.
Craun G (1991). Causes of waterborne outbreaks in the United States. 
Wat Sci Technol 24:17-20.
Craun GF (1993). Conference conclusions. In: (GF Craun, ed.) Safety 
of Water Disinfection: Balancing Chemical and Microbial Risks. 
International Life Sciences Inst. Press, Washington.
Craun G (1994). Memorandum from G. Craun to U.S. Environmental 
Protection Agency (P. Berger), dated 1/19/94. Waterborne outbreak 
data 1981-90, community water systems.
Cromwell JE, Zhang X, Letkiewicz FJ, et al. Analysis of potential 
tradeoffs in regulation of disinfection by-products. Office of Water 
Resource Center. Washington D.C. EPA-811-R-92-008. 1992.
Current WL, NC Reese, JV Ernst, WS Bailey, MB Heyman and WM 
Weinstein (1983). Human cryptosporidiosis in immunocompetent and 
immunodeficient persons. New Eng J Med 308(21): 1252-1257.
D'Antonio RG, RE Winn, JP Taylor, et al. (1985). A waterborne 
outbreak of cryptosporidiosis in normal hosts. Ann. Intern. Med. 
103:886-888.
De Mol P, S Mukashema, J Bogaerts, W Hemelhof and J-P Butzler 
(1984). Cryptosporidium related to measles diarrhoea in Rwanda. 
Lancet 2(8393): 42-43.
EPA. Environmental Protection Agency (1983). Assessment of 
Microbiology and Turbidity Standards for Drinking Water. EPA 570-9-
83-001. Washington, DC.
EPA. Environmental Protection Agency (1989a). Regulatory Impact 
Analysis: Benefits and Costs of Final Surface Water Treatment Rule, 
prepared by Wade Miller Associates, Inc., February 17, 1989, 
Washington, DC.
EPA. Environmental Protection Agency (1989b). Cross-Connection 
Control Manual. EPA 570/9-89-007. Washington, DC.
EPA. Environmental Protection Agency (1991a). Guidance Manual for 
Compliance With the Filtration and Disinfection Requirements for 
Public Water Systems Using Surface Water Sources. Washington, DC.
EPA. Environmental Protection Agency (1991b). Manual of Small Public 
Water Supply Systems. EPA 570/9-91-003. Washington, DC.
EPA. Environmental Protection Agency (1991c). Manual of Individual 
and Non-Public Water Supply Systems. EPA 570/9-91-004. Washington, 
DC.
EPA. Environmental Protection Agency (1992). Consensus method for 
determining groundwaters under the direct influence of surface water 
using microscopic particulate analysis (MPA). EPA 910/9-92-029.
EPA. Environmental Protection Agency (1993). Drinking Water Criteria 
Document for Cryptosporidium (Draft). Office of Science and 
Technology (Office of Water), EPA, Washington, DC.
EPA. Environmental Protection Agency (1994). Regulatory Impact 
Analysis of Proposed Interim Enhanced Surface Water Treatment Rule 
(Draft). Office of Ground Water and Drinking Water.
Ernest J, B Blagburn, D Lindsay and W Current (1986). Infection 
dynamics of Cryptosporidium parvum (Apicomplexa: Cryptosporidiidae) 
in neonatal mice (Mus musculus). J Parasitology 72(5):796-798.
Fayer R, and BLP Ungar (1986). Cryptosporidium spp. and 
cryptosporidiosis. Microbiol. Rev. 50:458-483.
Gerba, C, and J. Rose. (1990). Viruses in source and drinking water. 
Chap.18, pp 380-396. In: G. McFeters (ed), Drinking Water 
Microbiology. Springer-Verlag, New York.
Glass RI, JF Lew, RE Gangarosa, CW LeBaron and M-S Ho (1991). 
Estimates of morbidity and mortality rates for diarrheal diseases in 
American children. J Pediatrics 118: 27-33.
Grubbs WD, Macler B. Regli S. (1992). Modelling Giardia occurrence 
and risk. EPA-811-B-92-005. Office of Water Resource Center. 
Washington D.C.
Haas CN, JB Rose, C Gerba, S Regli (1993). Risk assessment of virus 
in drinking water. Risk Analysis 13: 545-552.
Harrington, W.A., Krupnick, A.J., and Spofford, W.O.,Jr.. The 
Benefits of Preventing an Outbreak of Giardiasis Due to Drinking 
Water Contamination. Resources for the Future, 1616P Street, NW., 
Washington, DC. September, 1985.
Hayes EB, TD Matte, TR O'Brien, TW McKinley, GS Logsdon, JB Rose, 
BLP Ungar, DM Word, PF Pinsky, ML Cummings, MA Wilson, EG Long, ES 
Hurwitz and DD Juranek (1989). Large community outbreak of 
cryptosporidiosis due to contamination of a filtered public water 
supply. New Eng J Med 320: 1372-1376.
Herwaldt BL, GF Craun, SL Stokes and DD Juranek (1991). Waterborne 
disease outbreaks, 1989-1990. In: CDC Surveillance Summaries, 
Morbidity and Mortality Weekly Report: 40(SS-3): 1-21. Hurst C 
(1991). Presence of enteric viruses in freshwater and their removal 
by conventional drinking water treatment process. Bull World Health 
Org. 69 (1): 113-119.
Keswick, BH, et al (1985). Inactivation of Norwalk virus in drinking 
water by chlorine. Appl. Environ. Microbiol. 50: 261-264.
Korich DG, JR Mead, MS Madore, NA Sinclair and CR Sterling (1990). 
Effects of ozone, chlorine dioxide and monochloramine on 
Cryptosporidium parvum oocyst viability. Appl Environ Microbiol 56: 
1423-1428.
Korich D, M Yozwiak, M Marshall, M Arrowood, N Sinclair, and C 
Sterling (1992). Cryptosporidium viability: assessment and 
correlation with infectivity. Water Quality Technology Conference 
Proceedings, 1991, I: 65-74. American Water Works Assoc, Denver.
LeChevallier MW, DN Norton and RG Lee (1991a). Occurrence of Giardia 
and Cryptosporidium spp. in surface water supplies. Appl Environ 
Microbiol 57: 2610-2616.
LeChevallier MW, DN Norton and RG Lee (1991b). Giardia and 
Cryptosporidium spp. in filtered drinking water supplies. Appl 
Environ Microbiol 57:2617-2621.
Levine WC and GF Craun (1990). Waterborne disease outbreaks, 1986-
1988. In: CDC Surveillance Summaries, Morbidity and Mortality Weekly 
Report 39(SS-1): 1-13.
Lew JF, RI Glass, RE Gangarosa, IP Cohen, C Bern and CL Moe (1991). 
Diarrheal deaths in the United States, 1979 through 1987. A special 
problem for the elderly. J Am Med Assoc 265: 3280-3284.
Lopez et al. (1980). Waterborne giardiasis: a communitywide outbreak 
of disease and a high rate of asymptomatic infection. Am J Epid 112: 
495-507.
Macler BA and S Regli (1993). Use of microbial risk assessment in 
setting US drinking water standards. Int J Food Microbiol 18: 245-
256.
Miller RA, MA Bronsdon and WR Morton (1990). Experimental 
cryptosporidiosis in a primate model. J Infect Dis 161: 312-315.
Moore AC, BL Herwaldt, GF Craun, RL Calderon, AK Highsmith, and DD 
Juranek (1993). Surveillance for waterborne disease outbreaks--
United States, 1991-1992. Morbidity and Mortality Weekly Report: 
42(SS-5): 1-22.
Payment, 1981. Isolation of viruses from drinking water at the 
Point-Viau water treatment plant. Can. J. Microbiol. 27:417.
Payment P, M Trudel, et al., (1985). Elimination of viruses and 
indicator bacteria at each step of treatment during preparation of 
drinking water at seven water treatment plants. Appl. Environ. 
Microbiol. 49:1418-1428.
Payment P, L Richardson, J Siemiatychi, R Dewar, M Edwardes and E 
Franco (1991). A randomized trial to evaluate the risk of 
gastrointestinal disease due to consumption of drinking water 
meeting current microbiological standards. Am J Publ Health 81: 703-
708.
Regli S, JB Rose, CN Haas and CP Gerba (1991). Modeling the risk 
from Giardia and viruses in drinking water. J Am Water Works Assoc 
83 (11): 76-84.
Regli S, JE Cromwell, X Zhang, AB Gelderloos, WD Grubbs, F 
Letkiewicz and BA Macler (1993). Framework for decision making: EPA 
perspective. In: (GF Craun, ed.) Safety of water disinfection: 
Balancing chemical and microbial risk. pp 487-538. International 
Life Sciences Institute Press, Washington, DC.
Rendtorff RC (1954). The experimental transmission of human 
intestinal protozoan parasites. II. Giardia lamblia cysts given in 
capsules. Am J Hyg 59: 209-220.
Rose JB, CN Haas and S Regli (1991). Risk assessment and control of 
waterborne giardiasis. Am J Publ Health 81: 709-713.
Smith HV, RWA Girdwood, WJ Patterson, et al. (1988). Waterborne 
outbreak of cryptosporidiosis. Lancet 2: 1484.
Sobsey MD, F Takashi, and RM Hall (1991). Inactivation of cell-
associated and dispersed Hepatitis A virus in water. J Am Water 
Works Assoc 83 (11): 64-67.
Williams, F (1985). Membrane-associated viral complexes observed in 
stools and cell culture. Appl. Environ. Microbiol. 50:523-526.
Wittenberg DF, NM Miller and J van den Ende (1989). Spiramycin is 
not effective in treating Cryptosporidium diarrhea in infants: 
results of a double-blind randomized trial. J Infect Dis 159(1): 
131-132.
Wolfe, MS (1990). Clinical symptoms and diagnosis by traditional 
methods. Pp. 175-185, In: Giardiasis (EA Meyer, ed.), Elsevier, New 
York.

List of Subjects

40 CFR Part 141

    Intergovernmental relations, Reporting and recordkeeping 
requirements, Water supply.

40 CFR Part 142

    Administrative practice and procedure, Reporting and recordkeeping 
requirements, Water supply

    Dated: June 7, 1994.
Carol M. Browner,
Administrator.

    For the reasons set forth in the preamble, Title 40 of the Code of 
Federal Regulations is proposed to be amended as follows:

PART 141--NATIONAL PRIMARY DRINKING WATER REGULATIONS

    1. The authority citation for part 141 continues to read as 
follows:

    Authority: 42 U.S.C. 300f, 300g-1, 300g-2, 300g-3, 300g-4, 300g-
5, 300g-6, 300j-4, 300j-9.

    2. Section 141.2 is amended by revising the definition of ``Ground 
water under the direct influence of surface water'' to read as follows:


Sec. 141.2  Definitions.

* * * * *
    Ground water under the direct influence of surface water means any 
water beneath the surface of the ground with:
    (1) Significant occurrence of insects or other macroorganisms, 
algae, or large-diameter pathogens such as Giardia lamblia or 
Cryptosporidium, or
    (2) Significant and relatively rapid shifts in water 
characteristics such as turbidity, temperature, conductivity, or pH 
which closely correlate to climatological or surface water conditions. 
Direct influence must be determined for individual sources in 
accordance with criteria established by the State. The State 
determination of direct influence may be based on site- specific 
measurements of water quality and/or documentation of well construction 
characteristics and geology with field evaluation.
* * * * *
    3. In Sec. 141.52, the Table is amended by adding a new entry, in 
numerical order, to read as follows:


Sec. 141.52  Maximum contaminant level goals for microbiological 
contaminants.

* * * * * 

------------------------------------------------------------------------
                          Contaminant                              MCLG 
------------------------------------------------------------------------
                                                                        
                                                                        
                                * * * * *                               
(5) Cryptosporidium.............................................  zero  
------------------------------------------------------------------------

    4. Section 141.71 is amended by revising the first three sentences 
of paragraph (b)(2) introductory text to read as follows:


Sec. 141.71  Criteria for avoiding filtration.

* * * * *
    (b) * * *
    (2) The public water system must maintain a watershed control 
program which minimizes the potential for contamination by Giardia 
lamblia cysts, Cryptosporidium oocysts, and viruses in the source 
water. The State must determine whether the watershed control program 
is adequate to meet this goal. The adequacy of a program to limit 
potential contamination by Giardia lamblia cysts, Cryptosporidium 
oocysts, and viruses must be based on: * * *
    5. Section 141.73 is amended by revising paragraph (d) to read as 
follows:


Sec. 141.73  Filtration.

* * * * *
    (d) Other filtration technologies. A public water system may use a 
filtration technology not listed in paragraphs (a) through (c) of this 
section if it demonstrates to the State, using pilot plant studies or 
other means, that the alternative filtration technology, in combination 
with disinfection treatment that meets the requirements of 
Sec. 141.72(b), consistently achieves 99.9 percent removal and/or 
inactivation of Giardia lamblia cysts and 99.99 percent removal and/or 
inactivation of viruses and 99 percent removal of Cryptosporidium 
oocysts between the source water and the first customer. For a system 
that makes this demonstration the requirements of paragraph (b) of this 
section apply.
    6. Section 141.74 is amended by adding a new paragraph (d) to read 
as follows:


Sec. 141.74  Analytical and monitoring requirements.

* * * * *
    (d) Sanitary surveys for all systems. (1) A public water system 
that uses a surface water source or a ground water source under the 
influence of surface water shall be subject to an initial sanitary 
survey by [insert date 5 years after publication of the final rule] and 
a subsequent sanitary survey every five years [ALTERNATIVE: every three 
years] thereafter.
    (2) The sanitary survey shall be performed by either the State, or 
an agent approved by the State. An agent approved by the State shall be 
paid by the system. In exceptional circumstances, the State may approve 
the public water system to conduct its own sanitary survey. In this 
case, the public water system shall certify that the system conducted 
the sanitary survey is in accordance with Sec. 141.2 and that the 
sanitary survey report is true and accurate.
    (3) If the State or an agent approved by the State is not available 
to conduct the sanitary survey within the time frame specified in this 
section, the system must conduct the sanitary survey. If an agent 
approved by the State or the system itself conducts the sanitary 
survey, the system must submit the sanitary survey report to the State 
within 90 days of completing the survey and before the end of the five 
year period.

Alternative A

    7. Section 141.70 is amended by revising paragraph (a)(1) to read 
as follows:


Sec. 141.70  General requirements.

    (a) * * *
    (1)(i) At least 99.9 percent (3-log) removal and/or inactivation of 
Giardia lamblia cysts for systems serving fewer than 10,000 people. A 
system serving 10,000 people or more must achieve a Giardia removal/
inactivation level by [insert date 18 months after publication of the 
final rule in the Federal Register that depends on the concentration of 
Giardia in the source water(s), as follows:
    (A) If the source water(s) contains less than 1 cyst/100 liters, 
the system must achieve at least 99.9 percent (3-log) reduction;
    (B) If the source water(s) contains 1 to 9 cysts/100 liters, the 
system must achieve at least 99.99 percent (4-log) reduction [OPTION: 
99.9 percent (3-log) reduction];
    (C) If the source water(s) contains 10 to 99 cysts/100 liters, the 
system must achieve at least 99.999 percent (5-log) reduction [OPTION: 
99.99 percent (4-log) reduction];
    (D) If the source water(s) contains more than 99 cysts/ 100 liters, 
the system must achieve at least 99.9999 percent (6-log) reduction 
[OPTION: 99.999 percent (5-log) reduction].
    (ii) Systems must achieve the required Giardia removal/inactivation 
level, as specified above, between the source water and the first 
customer. To calculate the Giardia density in source water from 
monitoring data obtained during the sampling period specified by 
Sec. 141.140 of this part, use the:
    Option 1: Arithmetic mean of measured values.
    Option 2: Geometric mean of measured values.
    Option 3: 90th percentile value of measured values.
    Option 4: Highest measured value.
* * * * *

Alternative B

    8. Section 141.70 is amended by adding new paragraph (a)(3) to read 
as follows:


Sec. 141.70  General requirements.

    (a) * * *
    (3) Beginning 18 months after promulgation of this rule, a system 
serving 10,000 people or more must achieve a Cryptosporidium removal/
inactivation level between the source water and first customer that 
depends on the concentration of Cryptosporidium in the source water(s), 
as follows:
    (i) If the source water(s) contains less than 1 oocyst/100 liters, 
the system must achieve at least 99.9 percent (3-log) reduction 
[OPTION: 99 percent (2-log) reduction];
    (ii) If the source water(s) contains 1 to 9 oocysts/100 liters, the 
system must achieve at least 99.99 percent (4-log) reduction [OPTION 1: 
99.9 percent (3-log) reduction; OPTION 2: 99 percent (2-log) 
reduction];
    (iii) If the source water(s) contains 10 to 99 oocysts/100 liters, 
the system must achieve at least 99.999 percent (5-log) reduction 
[OPTION 1: 99.99 percent (4-log) reduction; OPTION 2: 99.9 percent (3-
log) reduction];
    (iv) If the source water(s) contains more than 99 oocysts/ 100 
liters, the system must achieve at least 99.9999 percent (6-log) 
reduction [OPTION 1: 99.999 percent (5-log) reduction; OPTION 2: 99.99 
percent (4-log) reduction];
    Systems must achieve the required Cryptosporidium removal/
inactivation level, as specified above, between the source water and 
the first customer. To calculate the Cryptosporidium density in source 
water from monitoring data obtained during the sampling period 
specified by section 141.140 of this part, use the:
    Option 1: Arithmetic mean of measured values.
    Option 2: Geometric mean of measured values.
    Option 3: 90th percentile value of measured values.
    Option 4: Highest measured value.
* * * * *

Alternative C

    9. Section 141.73 is amended by adding a new paragraph (e) to read 
as follows:


Sec. 141.73  Filtration.

* * * * *
    (e) Public water systems that filter their source water must 
achieve at least 99 percent (2-log) removal of Cryptosporidium between 
the source water and the first customer.

Alternative D

    10. Section 141.72 is amended by adding a new paragraph (c) to read 
as follows:


Sec. 141.72  Disinfection.

* * * * *
    (c) Public water systems that serve 10,000 people or more and use 
either surface water or ground water under the direct influence of 
surface water must achieve, by disinfection alone, at least a 0.5-log 
inactivation of Giardia [ALTERNATIVE 1: 4-log inactivation of viruses].

Alternative E

    11. No change in existing SWTR regarding level of removal/
inactivation requirements.

PART 142--NATIONAL PRIMARY DRINKING WATER REGULATIONS 
IMPLEMENTATION

    1. The authority citation for part 142 continues to read as 
follows:

    Authority: 42 U.S.C. 300f, 300g-1, 300g-2 300g-3, 300g-4, 300g-
5, 300g-6, 300j-4, 300j-9.

    2. Section 142.16 is amended by adding paragraph (g) to read as 
follows:


Sec. 142.16  Special primacy requirements.

* * * * *
    (g) An application for approval of a State program revision that 
adopts the requirement specified below must contain the following:
    (1) The State must designate the method it will use to judge the 
adequacy of watershed protection programs in minimizing the potential 
for contamination by Giardia lamblia cysts, Cryptosporidium oocysts, 
and viruses in the source water.
    (2) The State must describe its criteria for the conduct of 
sanitary surveys and the method it will use to judge the adequacy of 
each sanitary survey. If the State elects to allow non-State personnel 
to conduct the surveys, the State must specify the criteria to be used 
to approve the non-State personnel. If the State intends to allow 
public water systems to conduct sanitary surveys, the State must 
specify procedures it will use for oversight and review of the surveys.

Alternative A

    3. The following special primacy requirements are associated with 
Alternative A from item 7, above.
    (3) Section 141.70(a)(1). The State must demonstrate that it has in 
place enforceable design and operating criteria for achieving the 
levels of Giardia lamblia removal/inactivation required. Alternatively, 
the State may institute a procedure for establishing design and 
operating conditions on a system-by-system basis (e.g., a permit 
system).

Alternative B

    4. The following special primacy requirements are associated with 
Alternative B from item 8, above.
    (3) Section 141.70(a)(3). The State must demonstrate that it has in 
place enforceable design and operating criteria for achieving the 
levels of Cryptosporidium removal/inactivation required. Alternatively, 
the State may institute a procedure for establishing design and 
operating conditions on a system-by-system basis (e.g., a permit 
system).

Alternative C

    5. The following special primacy requirements are associated with 
Alternative C from item 9, above.
    (3) Section 141.73(e). The State must demonstrate that it has in 
place enforceable design and operating criteria for achieving 2-log 
removal of Cryptosporidium between the source water and the first 
customer. Alternatively, the State may institute a procedure for 
establishing design and operating conditions on a system-by-system 
basis. (e.g., a permit system)

Alternative D

    6. The following special primacy requirements are associated with 
Alternative D from item 10, above.
    (4) Section 141.72(c). The State must demonstrate that it has in 
place enforceable design and operating criteria for achieving the level 
of Giardia (virus) inactivation required. Alternatively, the State may 
institute a procedure for establishing design and operating conditions 
on a system-by-system basis (e.g., a permit system).
[FR Doc. 94-17650 Filed 7-28-94; 8:45 am]
BILLING CODE 6560-50-P