[Federal Register Volume 59, Number 75 (Tuesday, April 19, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-9295]


[[Page Unknown]]

[Federal Register: April 19, 1994]


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Part VII





Environmental Protection Agency





_______________________________________________________________________




Combined Sewer Overflow (CSO) Control Policy; Notice
ENVIRONMENTAL PROTECTION AGENCY

[FRL-4732-7]

 
Combined Sewer Overflow (CSO) Control Policy

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final policy.

-----------------------------------------------------------------------

SUMMARY: EPA has issued a national policy statement entitled ``Combined 
Sewer Overflow (CSO) Control Policy.'' This policy establishes a 
consistent national approach for controlling discharges from CSOs to 
the Nation's waters through the National Pollutant Discharge 
Elimination System (NPDES) permit program.

FOR FURTHER INFORMATION CONTACT: Jeffrey Lape, Office of Wastewater 
Enforcement and Compliance, MC-4201, U.S. Environmental Protection 
Agency, 401 M Street SW., Washington, DC 20460, (202) 260-7361.

SUPPLEMENTARY INFORMATION: The main purposes of the CSO Control Policy 
are to elaborate on the Environmental Protection Agency's (EPA's) 
National CSO Control Strategy published on September 8, 1989, at 54 FR 
37370, and to expedite compliance with the requirements of the Clean 
Water Act (CWA). While implementation of the 1989 Strategy has resulted 
in progress toward controlling CSOs, significant public health and 
water quality risks remain.
    This Policy provides guidance to permittees with CSOs, NPDES 
authorities and State water quality standards authorities on 
coordinating the planning, selection, and implementation of CSO 
controls that meet the requirements of the CWA and allow for public 
involvement during the decision-making process.
    Contained in the Policy are provisions for developing appropriate, 
site-specific NPDES permit requirements for all combined sewer systems 
(CSS) that overflow as a result of wet weather events. For example, the 
Policy lays out two alternative approaches--the ``demonstration'' and 
the ``presumption'' approaches--that provide communities with targets 
for CSO controls that achieve compliance with the Act, particularly 
protection of water quality and designated uses. The Policy also 
includes enforcement initiatives to require the immediate elimination 
of overflows that occur during dry weather and to ensure that the 
remaining CWA requirements are complied with as soon as practicable.
    The permitting provisions of the Policy were developed as a result 
of extensive input received from key stakeholders during a negotiated 
policy dialogue. The CSO stakeholders included representatives from 
States, environmental groups, municipal organizations and others. The 
negotiated dialogue was conducted during the Summer of 1992 by the 
Office of Water and the Office of Water's Management Advisory Group. 
The enforcement initiatives, including one which is underway to address 
CSOs during dry weather, were developed by EPA's Office of Water and 
Office of Enforcement.
    EPA issued a Notice of Availability on the draft CSO Control Policy 
on January 19, 1993, (58 FR 4994) and requested comments on the draft 
Policy by March 22, 1993. Approximately forty-one sets of written 
comments were submitted by a variety of interest groups including 
cities and municipal groups, environmental groups, States, professional 
organizations and others. All comments were considered as EPA prepared 
the Final Policy. The public comments were largely supportive of the 
draft Policy. EPA received broad endorsement of and support for the key 
principles and provisions from most commenters. Thus, this final Policy 
does not include significant changes to the major provisions of the 
draft Policy, but rather, it includes clarification and better 
explanation of the elements of the Policy to address several of the 
questions that were raised in the comments. Persons wishing to obtain 
copies of the public comments or EPA's summary analysis of the comments 
may write or call the EPA contact person.
    The CSO Policy represents a comprehensive national strategy to 
ensure that municipalities, permitting authorities, water quality 
standards authorities and the public engage in a comprehensive and 
coordinated planning effort to achieve cost effective CSO controls that 
ultimately meet appropriate health and environmental objectives. The 
Policy recognizes the site-specific nature of CSOs and their impacts 
and provides the necessary flexibility to tailor controls to local 
situations. Major elements of the Policy ensure that CSO controls are 
cost effective and meet the objectives and requirements of the CWA.
    The major provisions of the Policy are as follows.
    CSO permittees should immediately undertake a process to accurately 
characterize their CSS and CSO discharges, demonstrate implementation 
of minimum technology-based controls identified in the Policy, and 
develop long-term CSO control plans which evaluate alternatives for 
attaining compliance with the CWA, including compliance with water 
quality standards and protection of designated uses. Once the long-term 
CSO control plans are completed, permittees will be responsible to 
implement the plans' recommendations as soon as practicable.
    State water quality standards authorities will be involved in the 
long-term CSO control planning effort as well. The water quality 
standards authorities will help ensure that development of the CSO 
permittees' long-term CSO control plans are coordinated with the review 
and possible revision of water quality standards on CSO-impacted 
waters.
    NPDES authorities will issue/reissue or modify permits, as 
appropriate, to require compliance with the technology-based and water 
quality-based requirements of the CWA. After completion of the long-
term CSO control plan, NPDES permits will be reissued or modified to 
incorporate the additional requirements specified in the Policy, such 
as performance standards for the selected controls based on average 
design conditions, a post-construction water quality assessment 
program, monitoring for compliance with water quality standards, and a 
reopener clause authorizing the NPDES authority to reopen and modify 
the permit if it is determined that the CSO controls fail to meet water 
quality standards or protect designated uses. NPDES authorities should 
commence enforcement actions against permittees that have CWA 
violations due to CSO discharges during dry weather. In addition, NPDES 
authorities should ensure the implementation of the minimum technology-
based controls and incorporate a schedule into an appropriate 
enforceable mechanism, with appropriate milestone dates, to implement 
the required long-term CSO control plan. Schedules for implementation 
of the long-term CSO control plan may be phased based on the relative 
importance of adverse impacts upon water quality standards and 
designated uses, and on a permittee's financial capability.
    EPA is developing extensive guidance to support the Policy and will 
announce the availability of the guidances and other outreach efforts 
through various means, as they become available. For example, EPA is 
preparing guidance on the nine minimum controls, characterization and 
monitoring of CSOs, development of long-term CSO control plans, and 
financial capability.
    Permittees will be expected to comply with any existing CSO-related 
requirements in NPDES permits, consent decrees or court orders unless 
revised to be consistent with this Policy.
    The policy is organized as follows:

I. Introduction
    A. Purpose and Principles
    B. Application of Policy
    C. Effect on Current CSO Control Efforts
    D. Small System Considerations
    E. Implementation Responsibilities
    F. Policy Development
II. EPA Objectives for Permittees
    A. Overview
    B. Implementation of the Nine Minimum Controls
    C. Long-Term CSO Control Plan
    1. Characterization, Monitoring, and Modeling of the Combined 
Sewer Systems
    2. Public Participation
    3. Consideration of Sensitive Areas
    4. Evaluation of Alternatives
    5. Cost/Performance Consideration
    6. Operational Plan
    7. Maximizing Treatment at the Existing POTW Treatment Plant
    8. Implementation Schedule
    9. Post-Construction Compliance Monitoring Program
III. Coordination With State Water Quality Standards
    A. Overview
    B. Water Quality Standards Reviews
IV. Expectations for Permitting Authorities
    A. Overview
    B. NPDES Permit Requirements
    1. Phase I Permits--Requirements for Demonstration of the Nine 
Minimum Controls and Development of the Long-Term CSO Control Plan
    2. Phase II Permits--Requirements for Implementation of a Long-
Term CSO Control Plan
    3. Phasing Considerations
V. Enforcement and Compliance
    A. Overview
    B. Enforcement of CSO Dry Weather Discharge Prohibition
    C. Enforcement of Wet Weather CSO Requirements
    1. Enforcement for Compliance With Phase I Permits
    2. Enforcement for Compliance With Phase II Permits
    D. Penalties

List of Subjects in 40 CFR Part 122

    Water pollution control.

    Authority: Clean Water Act, 33 U.S.C. 1251 et seq. 

    Dated: April 8, 1994.
Carol M. Browner,
Administrator.

Combined Sewer Overflow (CSO) Control Policy

I. Introduction

A. Purpose and Principles
    The main purposes of this Policy are to elaborate on EPA's National 
Combined Sewer Overflow (CSO) Control Strategy published on September 
8, 1989 at 54 FR 37370 (1989 Strategy) and to expedite compliance with 
the requirements of the Clean Water Act (CWA). While implementation of 
the 1989 Strategy has resulted in progress toward controlling CSOs, 
significant water quality risks remain.
    A combined sewer system (CSS) is a wastewater collection system 
owned by a State or municipality (as defined by section 502(4) of the 
CWA) which conveys sanitary wastewaters (domestic, commercial and 
industrial wastewaters) and storm water through a single-pipe system to 
a Publicly Owned Treatment Works (POTW) Treatment Plant (as defined in 
40 CFR 403.3(p)). A CSO is the discharge from a CSS at a point prior to 
the POTW Treatment Plant. CSOs are point sources subject to NPDES 
permit requirements including both technology-based and water quality-
based requirements of the CWA. CSOs are not subject to secondary 
treatment requirements applicable to POTWs.
    CSOs consist of mixtures of domestic sewage, industrial and 
commercial wastewaters, and storm water runoff. CSOs often contain high 
levels of suspended solids, pathogenic microorganisms, toxic 
pollutants, floatables, nutrients, oxygen-demanding organic compounds, 
oil and grease, and other pollutants. CSOs can cause exceedances of 
water quality standards (WQS). Such exceedances may pose risks to human 
health, threaten aquatic life and its habitat, and impair the use and 
enjoyment of the Nation's waterways.
    This Policy is intended to provide guidance to permittees with 
CSOs, National Pollutant Discharge Elimination System (NPDES) 
permitting authorities, State water quality standards authorities and 
enforcement authorities. The purpose of the Policy is to coordinate the 
planning, selection, design and implementation of CSO management 
practices and controls to meet the requirements of the CWA and to 
involve the public fully during the decision making process.
    This Policy reiterates the objectives of the 1989 Strategy:

1. To ensure that if CSOs occur, they are only as a result of wet 
weather;
2. To bring all wet weather CSO discharge points into compliance with 
the technology-based and water quality-based requirements of the CWA; 
and
3. To minimize water quality, aquatic biota, and human health impacts 
from CSOs.

    This CSO Control Policy represents a comprehensive national 
strategy to ensure that municipalities, permitting authorities, water 
quality standards authorities and the public engage in a comprehensive 
and coordinated planning effort to achieve cost-effective CSO controls 
that ultimately meet appropriate health and environmental objectives 
and requirements. The Policy recognizes the site-specific nature of 
CSOs and their impacts and provides the necessary flexibility to tailor 
controls to local situations. Four key principles of the Policy ensure 
that CSO controls are cost-effective and meet the objectives of the 
CWA. The key principles are:

1. Providing clear levels of control that would be presumed to meet 
appropriate health and environmental objectives;
2. Providing sufficient flexibility to municipalities, especially 
financially disadvantaged communities, to consider the site-specific 
nature of CSOs and to determine the most cost-effective means of 
reducing pollutants and meeting CWA objectives and requirements;
3. Allowing a phased approach to implementation of CSO controls 
considering a community's financial capability; and
4. Review and revision, as appropriate, of water quality standards and 
their implementation procedures when developing CSO control plans to 
reflect the site-specific wet weather impacts of CSOs.

    This Policy is being issued in support of EPA's regulations and 
policy initiatives. This Policy is Agency guidance only and does not 
establish or affect legal rights or obligations. It does not establish 
a binding norm and is not finally determinative of the issues 
addressed. Agency decisions in any particular case will be made by 
applying the law and regulations on the basis of specific facts when 
permits are issued. The Administration has recommended that the 1994 
amendments to the CWA endorse this final Policy.
B. Application of Policy
    The permitting provisions of this Policy apply to all CSSs that 
overflow as a result of storm water flow, including snow melt runoff 
(40 CFR 122.26(b)(13)). Discharges from CSSs during dry weather are 
prohibited by the CWA. Accordingly, the permitting provisions of this 
Policy do not apply to CSOs during dry weather. Dry weather flow is the 
flow in a combined sewer that results from domestic sewage, groundwater 
infiltration, commercial and industrial wastewaters, and any other non-
precipitation related flows (e.g., tidal infiltration). In addition to 
the permitting provisions, the Enforcement and Compliance section of 
this Policy describes an enforcement initiative being developed for 
overflows that occur during dry weather.
    Consistent with the 1989 Strategy, 30 States that submitted CSO 
permitting strategies have received EPA approval or, in the case of one 
State, conditional approval of its strategy. States and EPA Regional 
Offices should review these strategies and negotiate appropriate 
revisions to them to implement this Policy. Permitting authorities are 
encouraged to evaluate water pollution control needs on a watershed 
management basis and coordinate CSO control efforts with other point 
and nonpoint source control activities.
C. Effect on Current CSO Control Efforts
    EPA recognizes that extensive work has been done by many Regions, 
States, and municipalities to abate CSOs. As such, portions of this 
Policy may already have been addressed by permittees' previous efforts 
to control CSOs. Therefore, portions of this Policy may not apply, as 
determined by the permitting authority on a case-by-case basis, under 
the following circumstances:
    1. Any permittee that, on the date of publication of this final 
Policy, has completed or substantially completed construction of CSO 
control facilities that are designed to meet WQS and protect designated 
uses, and where it has been determined that WQS are being or will be 
attained, is not covered by the initial planning and construction 
provisions in this Policy; however, the operational plan and post-
construction monitoring provisions continue to apply. If, after 
monitoring, it is determined that WQS are not being attained, the 
permittee should be required to submit a revised CSO control plan that, 
once implemented, will attain WQS.
    2. Any permittee that, on the date of publication of this final 
Policy, has substantially developed or is implementing a CSO control 
program pursuant to an existing permit or enforcement order, and such 
program is considered by the NPDES permitting authority to be adequate 
to meet WQS and protect designated uses and is reasonably equivalent to 
the treatment objectives of this Policy, should complete those 
facilities without further planning activities otherwise expected by 
this Policy. Such programs, however, should be reviewed and modified to 
be consistent with the sensitive area, financial capability, and post-
construction monitoring provisions of this Policy.
    3. Any permittee that has previously constructed CSO control 
facilities in an effort to comply with WQS but has failed to meet such 
applicable standards or to protect designated uses due to remaining 
CSOs may receive consideration for such efforts in future permits or 
enforceable orders for long-term CSO control planning, design and 
implementation.
    In the case of any ongoing or substantially completed CSO control 
effort, the NPDES permit or other enforceable mechanism, as 
appropriate, should be revised to include all appropriate permit 
requirements consistent with Section IV.B. of this Policy.
D. Small System Considerations
    The scope of the long-term CSO control plan, including the 
characterization, monitoring and modeling, and evaluation of 
alternatives portions of this Policy may be difficult for some small 
CSSs. At the discretion of the NPDES Authority, jurisdictions with 
populations under 75,000 may not need to complete each of the formal 
steps outlined in Section II.C. of this Policy, but should be required 
through their permits or other enforceable mechanisms to comply with 
the nine minimum controls (II.B), public participation (II.C.2), and 
sensitive areas (II.C.3) portions of this Policy. In addition, the 
permittee may propose to implement any of the criteria contained in 
this Policy for evaluation of alternatives described in II.C.4. 
Following approval of the proposed plan, such jurisdictions should 
construct the control projects and propose a monitoring program 
sufficient to determine whether WQS are attained and designated uses 
are protected.
    In developing long-term CSO control plans based on the small system 
considerations discussed in the preceding paragraph, permittees are 
encouraged to discuss the scope of their long-term CSO control plan 
with the WQS authority and the NPDES authority. These discussions will 
ensure that the plan includes sufficient information to enable the 
permitting authority to identify the appropriate CSO controls.
E. Implementation Responsibilities
    NPDES authorities (authorized States or EPA Regional Offices, as 
appropriate) are responsible for implementing this Policy. It is their 
responsibility to assure that CSO permittees develop long-term CSO 
control plans and that NPDES permits meet the requirements of the CWA. 
Further, they are responsible for coordinating the review of the long-
term CSO control plan and the development of the permit with the WQS 
authority to determine if revisions to the WQS are appropriate. In 
addition, they should determine the appropriate vehicle (i.e., permit 
reissuance, information request under CWA section 308 or State 
equivalent or enforcement action) to ensure that compliance with the 
CWA is achieved as soon as practicable.
    Permittees are responsible for documenting the implementation of 
the nine minimum controls and developing and implementing a long-term 
CSO control plan, as described in this Policy. EPA recognizes that 
financial considerations are a major factor affecting the 
implementation of CSO controls. For that reason, this Policy allows 
consideration of a permittee's financial capability in connection with 
the long-term CSO control planning effort, WQS review, and negotiation 
of enforceable schedules. However, each permittee is ultimately 
responsible for aggressively pursuing financial arrangements for the 
implementation of its long-term CSO control plan. As part of this 
effort, communities should apply to their State Revolving Fund program, 
or other assistance programs as appropriate, for financial assistance.
    EPA and the States will undertake action to assure that all 
permittees with CSSs are subject to a consistent review in the permit 
development process, have permit requirements that achieve compliance 
with the CWA, and are subject to enforceable schedules that require the 
earliest practicable compliance date considering physical and financial 
feasibility.
F. Policy Development
    This Policy devotes a separate section to each step involved in 
developing and implementing CSO controls. This is not to imply that 
each function occurs separately. Rather, the entire process surrounding 
CSO controls, community planning, WQS and permit development/revision, 
enforcement/compliance actions and public participation must be 
coordinated to control CSOs effectively. Permittees and permitting 
authorities are encouraged to consider innovative and alternative 
approaches and technologies that achieve the objectives of this Policy 
and the CWA.
    In developing this Policy, EPA has included information on what 
responsible parties are expected to accomplish. Subsequent documents 
will provide additional guidance on how the objectives of this Policy 
should be met. These documents will provide further guidance on: CSO 
permit writing, the nine minimum controls, long-term CSO control plans, 
financial capability, sewer system characterization and receiving water 
monitoring and modeling, and application of WQS to CSO-impacted waters. 
For most CSO control efforts however, sufficient detail has been 
included in this Policy to begin immediate implementation of its 
provisions.

II. EPA Objectives for Permittees

A. Overview
    Permittees with CSSs that have CSOs should immediately undertake a 
process to accurately characterize their sewer systems, to demonstrate 
implementation of the nine minimum controls, and to develop a long-term 
CSO control plan.
B. Implementation of the Nine Minimum Controls
    Permittees with CSOs should submit appropriate documentation 
demonstrating implementation of the nine minimum controls, including 
any proposed schedules for completing minor construction activities. 
The nine minimum controls are:
1. Proper operation and regular maintenance programs for the sewer 
system and the CSOs;
2. Maximum use of the collection system for storage;
3. Review and modification of pretreatment requirements to assure CSO 
impacts are minimized;
4. Maximization of flow to the POTW for treatment;
5. Prohibition of CSOs during dry weather;
6. Control of solid and floatable materials in CSOs;
7. Pollution prevention;
8. Public notification to ensure that the public receives adequate 
notification of CSO occurrences and CSO impacts; and
9. Monitoring to effectively characterize CSO impacts and the efficacy 
of CSO controls.

    Selection and implementation of actual control measures should be 
based on site-specific considerations including the specific CSS's 
characteristics discussed under the sewer system characterization and 
monitoring portions of this Policy. Documentation of the nine minimum 
controls may include operation and maintenance plans, revised sewer use 
ordinances for industrial users, sewer system inspection reports, 
infiltration/inflow studies, pollution prevention programs, public 
notification plans, and facility plans for maximizing the capacities of 
the existing collection, storage and treatment systems, as well as 
contracts and schedules for minor construction programs for improving 
the existing system's operation. The permittee should also submit any 
information or data on the degree to which the nine minimum controls 
achieve compliance with water quality standards. These data and 
information should include results made available through monitoring 
and modeling activities done in conjunction with the development of the 
long-term CSO control plan described in this Policy.
    This documentation should be submitted as soon as practicable, but 
no later than two years after the requirement to submit such 
documentation is included in an NPDES permit or other enforceable 
mechanism. Implementation of the nine minimum controls with appropriate 
documentation should be completed as soon as practicable but no later 
than January 1, 1997. These dates should be included in an appropriate 
enforceable mechanism.
    Because the CWA requires immediate compliance with technology-based 
controls (section 301(b)), which on a Best Professional Judgment basis 
should include the nine minimum controls, a compliance schedule for 
implementing the nine minimum controls, if necessary, should be 
included in an appropriate enforceable mechanism.
C. Long-Term CSO Control Plan
    Permittees with CSOs are responsible for developing and 
implementing long-term CSO control plans that will ultimately result in 
compliance with the requirements of the CWA. The long-term plans should 
consider the site-specific nature of CSOs and evaluate the cost 
effectiveness of a range of control options/strategies. The development 
of the long-term CSO control plan and its subsequent implementation 
should also be coordinated with the NPDES authority and the State 
authority responsible for reviewing and revising the State's WQS. The 
selected controls should be designed to allow cost effective expansion 
or cost effective retrofitting if additional controls are subsequently 
determined to be necessary to meet WQS, including existing and 
designated uses.
    This policy identifies EPA's major objectives for the long-term CSO 
control plan. Permittees should develop and submit this long-term CSO 
control plan as soon as practicable, but generally within two years 
after the date of the NPDES permit provision, Section 308 information 
request, or enforcement action requiring the permittee to develop the 
plan. NPDES authorities may establish a longer timetable for completion 
of the long-term CSO control plan on a case-by-case basis to account 
for site-specific factors which may influence the complexity of the 
planning process. Once agreed upon, these dates should be included in 
an appropriate enforceable mechanism.
    EPA expects each long-term CSO control plan to utilize appropriate 
information to address the following minimum elements. The Plan should 
also include both fixed-date project implementation schedules (which 
may be phased) and a financing plan to design and construct the project 
as soon as practicable. The minimum elements of the long-term CSO 
control plan are described below.
1. Characterization, Monitoring, and Modeling of the Combined Sewer 
System
    In order to design a CSO control plan adequate to meet the 
requirements of the CWA, a permittee should have a thorough 
understanding of its sewer system, the response of the system to 
various precipitation events, the characteristics of the overflows, and 
the water quality impacts that result from CSOs. The permittee should 
adequately characterize through monitoring, modeling, and other means 
as appropriate, for a range of storm events, the response of its sewer 
system to wet weather events including the number, location and 
frequency of CSOs, volume, concentration and mass of pollutants 
discharged and the impacts of the CSOs on the receiving waters and 
their designated uses. The permittee may need to consider information 
on the contribution and importance of other pollution sources in order 
to develop a final plan designed to meet water quality standards. The 
purpose of the system characterization, monitoring and modeling program 
initially is to assist the permittee in developing appropriate measures 
to implement the nine minimum controls and, if necessary, to support 
development of the long-term CSO control plan. The monitoring and 
modeling data also will be used to evaluate the expected effectiveness 
of both the nine minimum controls and, if necessary, the long-term CSO 
controls, to meet WQS.
    The major elements of a sewer system characterization are described 
below.
    a. Rainfall Records--The permittee should examine the complete 
rainfall record for the geographic area of its existing CSS using sound 
statistical procedures and best available data. The permittee should 
evaluate flow variations in the receiving water body to correlate 
between CSOs and receiving water conditions.
    b. Combined Sewer System Characterization--The permittee should 
evaluate the nature and extent of its sewer system through evaluation 
of available sewer system records, field inspections and other 
activities necessary to understand the number, location and frequency 
of overflows and their location relative to sensitive areas and to 
pollution sources in the collection system, such as indirect 
significant industrial users.
    c. CSO Monitoring--The permittee should develop a comprehensive, 
representative monitoring program that measures the frequency, 
duration, flow rate, volume and pollutant concentration of CSO 
discharges and assesses the impact of the CSOs on the receiving waters. 
The monitoring program should include necessary CSO effluent and 
ambient in-stream monitoring and, where appropriate, other monitoring 
protocols such as biological assessment, toxicity testing and sediment 
sampling. Monitoring parameters should include, for example, oxygen 
demanding pollutants, nutrients, toxic pollutants, sediment 
contaminants, pathogens, bacteriological indicators (e.g., 
Enterococcus, E. Coli), and toxicity. A representative sample of 
overflow points can be selected that is sufficient to allow 
characterization of CSO discharges and their water quality impacts and 
to facilitate evaluation of control plan alternatives.
    d. Modeling--Modeling of a sewer system is recognized as a valuable 
tool for predicting sewer system response to various wet weather events 
and assessing water quality impacts when evaluating different control 
strategies and alternatives. EPA supports the proper and effective use 
of models, where appropriate, in the evaluation of the nine minimum 
controls and the development of the long-term CSO control plan. It is 
also recognized that there are many models which may be used to do 
this. These models range from simple to complex. Having decided to use 
a model, the permittee should base its choice of a model on the 
characteristics of its sewer system, the number and location of 
overflow points, and the sensitivity of the receiving water body to the 
CSO discharges. Use of models should include appropriate calibration 
and verification with field measurements. The sophistication of the 
model should relate to the complexity of the system to be modeled and 
to the information needs associated with evaluation of CSO control 
options and water quality impacts. EPA believes that continuous 
simulation models, using historical rainfall data, may be the best way 
to model sewer systems, CSOs, and their impacts. Because of the 
iterative nature of modeling sewer systems, CSOs, and their impacts, 
monitoring and modeling efforts are complementary and should be 
coordinated.
2. Public Participation
    In developing its long-term CSO control plan, the permittee will 
employ a public participation process that actively involves the 
affected public in the decision-making to select the long-term CSO 
controls. The affected public includes rate payers, industrial users of 
the sewer system, persons who reside downstream from the CSOs, persons 
who use and enjoy these downstream waters, and any other interested 
persons.
3. Consideration of Sensitive Areas
    EPA expects a permittee's long-term CSO control plan to give the 
highest priority to controlling overflows to sensitive areas. Sensitive 
areas, as determined by the NPDES authority in coordination with State 
and Federal agencies, as appropriate, include designated Outstanding 
National Resource Waters, National Marine Sanctuaries, waters with 
threatened or endangered species and their habitat, waters with primary 
contact recreation, public drinking water intakes or their designated 
protection areas, and shellfish beds. For such areas, the long-term CSO 
control plan should:
    a. Prohibit new or significantly increased overflows;
    b. i. Eliminate or relocate overflows that discharge to sensitive 
areas wherever physically possible and economically achievable, except 
where elimination or relocation would provide less environmental 
protection than additional treatment; or
    ii. Where elimination or relocation is not physically possible and 
economically achievable, or would provide less environmental protection 
than additional treatment, provide the level of treatment for remaining 
overflows deemed necessary to meet WQS for full protection of existing 
and designated uses. In any event, the level of control should not be 
less than those described in Evaluation of Alternatives below; and
    c. Where elimination or relocation has been proven not to be 
physically possible and economically achievable, permitting authorities 
should require, for each subsequent permit term, a reassessment based 
on new or improved techniques to eliminate or relocate, or on changed 
circumstances that influence economic achievability.
4. Evaluation of Alternatives
    EPA expects the long-term CSO control plan to consider a reasonable 
range of alternatives. The plan should, for example, evaluate controls 
that would be necessary to achieve zero overflow events per year, an 
average of one to three, four to seven, and eight to twelve overflow 
events per year. Alternatively, the long-term plan could evaluate 
controls that achieve 100% capture, 90% capture, 85% capture, 80% 
capture, and 75% capture for treatment. The long-term control plan 
should also consider expansion of POTW secondary and primary capacity 
in the CSO abatement alternative analysis. The analysis of alternatives 
should be sufficient to make a reasonable assessment of cost and 
performance as described in Section II.C.5. Because the final long-term 
CSO control plan will become the basis for NPDES permit limits and 
requirements, the selected controls should be sufficient to meet CWA 
requirements.
    In addition to considering sensitive areas, the long-term CSO 
control plan should adopt one of the following approaches:
a. ``Presumption'' Approach
    A program that meets any of the criteria listed below would be 
presumed to provide an adequate level of control to meet the water 
quality-based requirements of the CWA, provided the permitting 
authority determines that such presumption is reasonable in light of 
the data and analysis conducted in the characterization, monitoring, 
and modeling of the system and the consideration of sensitive areas 
described above. These criteria are provided because data and modeling 
of wet weather events often do not give a clear picture of the level of 
CSO controls necessary to protect WQS.
    i. No more than an average of four overflow events per year, 
provided that the permitting authority may allow up to two additional 
overflow events per year. For the purpose of this criterion, an 
overflow event is one or more overflows from a CSS as the result of a 
precipitation event that does not receive the minimum treatment 
specified below; or
    ii. The elimination or the capture for treatment of no less than 
85% by volume of the combined sewage collected in the CSS during 
precipitation events on a system-wide annual average basis; or
    iii. The elimination or removal of no less than the mass of the 
pollutants, identified as causing water quality impairment through the 
sewer system characterization, monitoring, and modeling effort, for the 
volumes that would be eliminated or captured for treatment under 
paragraph ii. above.

Combined sewer flows remaining after implementation of the nine minimum 
controls and within the criteria specified at II.C.4.a.i or ii, should 
receive a minimum of:
     Primary clarification (Removal of floatables and 
settleable solids may be achieved by any combination of treatment 
technologies or methods that are shown to be equivalent to primary 
clarification.);
     Solids and floatables disposal; and
     Disinfection of effluent, if necessary, to meet WQS, 
protect designated uses and protect human health, including removal of 
harmful disinfection chemical residuals, where necessary.
b. ``Demonstration'' Approach
    A permittee may demonstrate that a selected control program, though 
not meeting the criteria specified in II.C.4.a. above is adequate to 
meet the water quality-based requirements of the CWA. To be a 
successful demonstration, the permittee should demonstrate each of the 
following:
    i. The planned control program is adequate to meet WQS and protect 
designated uses, unless WQS or uses cannot be met as a result of 
natural background conditions or pollution sources other than CSOs;
    ii. The CSO discharges remaining after implementation of the 
planned control program will not preclude the attainment of WQS or the 
receiving waters' designated uses or contribute to their impairment. 
Where WQS and designated uses are not met in part because of natural 
background conditions or pollution sources other than CSOs, a total 
maximum daily load, including a wasteload allocation and a load 
allocation, or other means should be used to apportion pollutant loads;
    iii. The planned control program will provide the maximum pollution 
reduction benefits reasonably attainable; and
    iv. The planned control program is designed to allow cost effective 
expansion or cost effective retrofitting if additional controls are 
subsequently determined to be necessary to meet WQS or designated uses.
5. Cost/Performance Considerations
    The permittee should develop appropriate cost/performance curves to 
demonstrate the relationships among a comprehensive set of reasonable 
control alternatives that correspond to the different ranges specified 
in Section II.C.4. This should include an analysis to determine where 
the increment of pollution reduction achieved in the receiving water 
diminishes compared to the increased costs. This analysis, often known 
as knee of the curve, should be among the considerations used to help 
guide selection of controls.
6. Operational Plan
    After agreement between the permittee and NPDES authority on the 
necessary CSO controls to be implemented under the long-term CSO 
control plan, the permittee should revise the operation and maintenance 
program developed as part of the nine minimum controls to include the 
agreed-upon long-term CSO controls. The revised operation and 
maintenance program should maximize the removal of pollutants during 
and after each precipitation event using all available facilities 
within the collection and treatment system. For any flows in excess of 
the criteria specified at II.C.4.a.i., ii. or iii and not receiving the 
treatment specified in II.C.4.a, the operational plan should ensure 
that such flows receive treatment to the greatest extent practicable.
7. Maximizing Treatment at the Existing POTW Treatment Plant
    In some communities, POTW treatment plants may have primary 
treatment capacity in excess of their secondary treatment capacity. One 
effective strategy to abate pollution resulting from CSOs is to 
maximize the delivery of flows during wet weather to the POTW treatment 
plant for treatment. Delivering these flows can have two significant 
water quality benefits: First, increased flows during wet weather to 
the POTW treatment plant may enable the permittee to eliminate or 
minimize overflows to sensitive areas; second, this would maximize the 
use of available POTW facilities for wet weather flows and would ensure 
that combined sewer flows receive at least primary treatment prior to 
discharge.
    Under EPA regulations, the intentional diversion of waste streams 
from any portion of a treatment facility, including secondary 
treatment, is a bypass. EPA bypass regulations at 40 CFR 122.41(m) 
allow for a facility to bypass some or all the flow from its treatment 
process under specified limited circumstances. Under the regulation, 
the permittee must show that the bypass was unavoidable to prevent loss 
of life, personal injury or severe property damage, that there was no 
feasible alternative to the bypass and that the permittee submitted the 
required notices. In addition, the regulation provides that a bypass 
may be approved only after consideration of adverse effects.
    Normally, it is the responsibility of the permittee to document, on 
a case-by-base basis, compliance with 40 CFR 122.41(m) in order to 
bypass flows legally. For some CSO-related permits, the study of 
feasible alternatives in the control plan may provide sufficient 
support for the permit record and for approval of a CSO-related bypass 
in the permit itself, and to define the specific parameters under which 
a bypass can legally occur. For approval of a CSO-related bypass, the 
long-term CSO control plan, at a minimum, should provide justification 
for the cut-off point at which the flow will be diverted from the 
secondary treatment portion of the treatment plant, and provide a 
benefit-cost analysis demonstrating that conveyance of wet weather flow 
to the POTW for primary treatment is more beneficial than other CSO 
abatement alternatives such as storage and pump back for secondary 
treatment, sewer separation, or satellite treatment. Such a permit must 
define under what specific wet weather conditions a CSO-related bypass 
is allowed and also specify what treatment or what monitoring, and 
effluent limitations and requirements apply to the bypass flow. The 
permit should also provide that approval for the CSO-related bypass 
will be reviewed and may be modified or terminated if there is a 
substantial increase in the volume or character of pollutants being 
introduced to the POTW. The CSO-related bypass provision in the permit 
should also make it clear that all wet weather flows passing the 
headworks of the POTW treatment plant will receive at least primary 
clarification and solids and floatables removal and disposal, and 
disinfection, where necessary, and any other treatment that can 
reasonably be provided.
    Under this approach, EPA would allow a permit to authorize a CSO-
related bypass of the secondary treatment portion of the POTW treatment 
plant for combined sewer flows in certain identified circumstances. 
This provision would apply only to those situations where the POTW 
would ordinarily meet the requirements of 40 CFR 122.41(m) as evaluated 
on a case-by-case basis. Therefore, there must be sufficient data in 
the administrative record (reflected in the permit fact sheet or 
statement of basis) supporting all the requirements in 40 CFR 
122.41(m)(4) for approval of an anticipated bypass.
    For the purposes of applying this regulation to CSO permittees, 
``severe property damage'' could include situations where flows above a 
certain level wash out the POTW's secondary treatment system. EPA 
further believes that the feasible alternatives requirement of the 
regulation can be met if the record shows that the secondary treatment 
system is properly operated and maintained, that the system has been 
designed to meet secondary limits for flows greater than the peak dry 
weather flow, plus an appropriate quantity of wet weather flow, and 
that it is either technically or financially infeasible to provide 
secondary treatment at the existing facilities for greater amounts of 
wet weather flow. The feasible alternative analysis should include, for 
example, consideration of enhanced primary treatment (e.g., chemical 
addition) and non-biological secondary treatment. Other bases 
supporting a finding of no feasible alternative may also be available 
on a case-by-case basis. As part of its consideration of possible 
adverse effects resulting from the bypass, the permitting authority 
should also ensure that the bypass will not cause exceedances of WQS.
    This Policy does not address the appropriateness of approving 
anticipated bypasses through NPDES permits in advance outside the CSO 
context.
8. Implementation Schedule
    The permittee should include all pertinent information in the long 
term control plan necessary to develop the construction and financing 
schedule for implementation of CSO controls. Schedules for 
implementation of the CSO controls may be phased based on the relative 
importance of adverse impacts upon WQS and designated uses, priority 
projects identified in the long-term plan, and on a permittee's 
financial capability.
    Construction phasing should consider:
    a. Eliminating overflows that discharge to sensitive areas as the 
highest priority;
    b. Use impairment;
    c. The permittee's financial capability including consideration of 
such factors as:
    i. Median household income;
    ii. Total annual wastewater and CSO control costs per household as 
a percent of median household income;
    iii. Overall net debt as a percent of full market property value;
    iv. Property tax revenues as a percent of full market property 
value;
    v. Property tax collection rate;
    vi. Unemployment; and
    vii. Bond rating;
    d. Grant and loan availability;
    e. Previous and current residential, commercial and industrial 
sewer user fees and rate structures; and
    f. Other viable funding mechanisms and sources of financing.
9. Post-Construction Compliance Monitoring Program
    The selected CSO controls should include a post-construction water 
quality monitoring program adequate to verify compliance with water 
quality standards and protection of designated uses as well as to 
ascertain the effectiveness of CSO controls. This water quality 
compliance monitoring program should include a plan to be approved by 
the NPDES authority that details the monitoring protocols to be 
followed, including the necessary effluent and ambient monitoring and, 
where appropriate, other monitoring protocols such as biological 
assessments, whole effluent toxicity testing, and sediment sampling.

III. Coordination With State Water Quality Standards

A. Overview
    WQS are State adopted, or Federally promulgated rules which serve 
as the goals for the water body and the legal basis for the water 
quality-based NPDES permit requirements under the CWA. WQS consist of 
uses which States designate for their water bodies, criteria to protect 
the uses, an anti-degradation policy to protect the water quality 
improvements gained and other policies affecting the implementation of 
the standards. A primary objective of the long-term CSO control plan is 
to meet WQS, including the designated uses through reducing risks to 
human health and the environment by eliminating, relocating or 
controlling CSOs to the affected waters.
    State WQS authorities, NPDES authorities, EPA regional offices, 
permittees, and the public should meet early and frequently throughout 
the long-term CSO control planning process. Development of the long-
term plan should be coordinated with the review and appropriate 
revision of WQS and implementation procedures on CSO-impacted waters to 
ensure that the long-term controls will be sufficient to meet water 
quality standards. As part of these meetings, participants should agree 
on the data, information and analyses needed to support the development 
of the long-term CSO control plan and the review of applicable WQS, and 
implementation procedures, if appropriate. Agreements should be reached 
on the monitoring protocols and models that will be used to evaluate 
the water quality impacts of the overflows, to analyze the 
attainability of the WQS and to determine the water quality-based 
requirements for the permit. Many opportunities exist for permittees 
and States to share information as control programs are developed and 
as WQS are reviewed. Such information should assist States in 
determining the need for revisions to WQS and implementation procedures 
to better reflect the site-specific wet weather impacts of CSOs. 
Coordinating the development of the long-term CSO control plan and the 
review of the WQS and implementation procedures provides greater 
assurance that the long-term control plan selected and the limits and 
requirements included in the NPDES permit will be sufficient to meet 
WQS and to comply with sections 301(b)(1)(C) and 402(a)(2) of the CWA.
    EPA encourages States and permittees jointly to sponsor workshops 
for the affected public in the development of the long-term CSO control 
plan and during the development of appropriate revisions to WQS for 
CSO-impacted waters. Workshops provide a forum for including the public 
in discussions of the implications of the proposed long-term CSO 
control plan on the water quality and uses for the receiving water.
B. Water Quality Standards Reviews
    The CWA requires States to periodically, but at least once every 
three years, hold public hearings for the purpose of reviewing 
applicable water quality standards and, as appropriate, modifying and 
adopting standards. States must provide the public an opportunity to 
comment on any proposed revision to water quality standards and all 
revisions must be submitted to EPA for review and approval.
    EPA regulations and guidance provide States with the flexibility to 
adapt their WQS, and implementation procedures to reflect site-specific 
conditions including those related to CSOs. For example, a State may 
adopt site-specific criteria for a particular pollutant if the State 
determines that the site-specific criteria fully protects the 
designated use (40 CFR 131.11). In addition, the regulations at 40 CFR 
131.10(g), (h), and (j) specify when and how a designated use may be 
modified. A State may remove a designated use from its water quality 
standards only if the designated use is not an existing use. An 
existing use is a use actually attained in the water body on or after 
November 28, 1975. Furthermore, a State may not remove a designated use 
that will be attained by implementing the technology-based effluent 
limits required under sections 301(b) and 306 of the CWA and by 
implementing cost-effective and reasonable best management practices 
for nonpoint source controls. Thus, if a State has a reasonable basis 
to determine that the current designated use could be attained after 
implementation of the technology-based controls of the CWA, then the 
use could not be removed.
    In determining whether a use is attainable and prior to removing a 
designated use, States must conduct and submit to EPA a use 
attainability analysis. A use attainability analysis is a structured 
scientific assessment of the factors affecting the use, including the 
physical, chemical, biological, and economic factors described in 40 
CFR 131.10(g). As part of the analysis, States should evaluate whether 
the designated use could be attained if CSO controls were implemented. 
For example, States should examine if sediment loadings from CSOs could 
be reduced so as not to bury spawning beds, or if biochemical oxygen 
demanding material in the effluent or the toxicity of the effluent 
could be corrected so as to reduce the acute or chronic physiological 
stress on or bioaccumulation potential of aquatic organisms.
    In reviewing the attainability of their WQS and the applicability 
of their implementation procedures to CSO-impacted waters, States are 
encouraged to define more explicitly their recreational and aquatic 
life uses and then, if appropriate, modify the criteria accordingly to 
protect the designated uses.
    Another option is for States to adopt partial uses by defining when 
primary contact recreation such as swimming does not exist, such as 
during certain seasons of the year in northern climates or during a 
particular type of storm event. In making such adjustments to their 
uses, States must ensure that downstream uses are protected, and that 
during other seasons or after the storm event has passed, the use is 
fully protected.
    In addition to defining recreational uses with greater specificity, 
States are also encouraged to define the aquatic uses more precisely. 
Rather than ``aquatic life use protection,'' States should consider 
defining the type of fishery to be protected such as a cold water 
fishery (e.g., trout or salmon) or a warm weather fishery (e.g., 
bluegill or large mouth bass). Explicitly defining the type of fishery 
to be protected may assist the permittee in enlisting the support of 
citizens for a CSO control plan.
    A water quality standard variance may be appropriate, in limited 
circumstances on CSO-impacted waters, where the State is uncertain as 
to whether a standard can be attained and time is needed for the State 
to conduct additional analyses on the attainability of the standard. 
Variances are short-term modifications in water quality standards. 
Subject to EPA approval, States, with their own statutory authority, 
may grant a variance to a specific discharger for a specific pollutant. 
The justification for a variance is similar to that required for a 
permanent change in the standard, although the showings needed are less 
rigorous. Variances are also subject to public participation 
requirements of the water quality standards and permits programs and 
are reviewable generally every three years. A variance allows the CSO 
permit to be written to meet the ``modified'' water quality standard as 
analyses are conducted and as progress is made to improve water 
quality.
    Justifications for variances are the same as those identified in 40 
CFR 131.10(g) for modifications in uses. States must provide an 
opportunity for public review and comment on all variances. If States 
use the permit as the vehicle to grant the variance, notice of the 
permit must clearly state that the variance modifies the State's water 
quality standards. If the variance is approved, the State appends the 
variance to the State's standards and reviews the variance every three 
years.

IV. Expectations for Permitting Authorities

A. Overview
    CSOs are point sources subject to NPDES permit requirements 
including both technology-based and water quality-based requirements of 
the CWA. CSOs are not subject to secondary treatment regulations 
applicable to publicly owned treatment works (Montgomery Environmental 
Coalition vs. Costle, 646 F.2d 568 (D.C. Cir. 1980)).
    All permits for CSOs should require the nine minimum controls as a 
minimum best available technology economically achievable and best 
conventional technology (BAT/BCT) established on a best professional 
judgment (BPJ) basis by the permitting authority (40 CFR 125.3). Water 
quality-based requirements are to be established based on applicable 
water quality standards.
    This policy establishes a uniform, nationally consistent approach 
to developing and issuing NPDES permits to permittees with CSOs. 
Permits for CSOs should be developed and issued expeditiously. A 
single, system-wide permit generally should be issued for all 
discharges, including CSOs, from a CSS operated by a single authority. 
When different parts of a single CSS are operated by more than one 
authority, permits issued to each authority should generally require 
joint preparation and implementation of the elements of this Policy and 
should specifically define the responsibilities and duties of each 
authority. Permittees should be required to coordinate system-wide 
implementation of the nine minimum controls and the development and 
implementation of the long-term CSO control plan.
    The individual authorities are responsible for their own discharges 
and should cooperate with the permittee for the POTW receiving the 
flows from the CSS. When a CSO is permitted separately from the POTW, 
both permits should be cross-referenced for informational purposes.
    EPA Regions and States should review the CSO permitting priorities 
established in the State CSO Permitting Strategies developed in 
response to the 1989 Strategy. Regions and States may elect to revise 
these previous priorities. In setting permitting priorities, Regions 
and States should not just focus on those permittees that have 
initiated monitoring programs. When setting priorities, Regions and 
States should consider, for example, the known or potential impact of 
CSOs on sensitive areas, and the extent of upstream industrial user 
discharges to the CSS.
    During the permittee's development of the long-term CSO control 
plan, the permit writer should promote coordination between the 
permittee and State WQS authority in connection with possible WQS 
revisions. Once the permittee has completed development of the long-
term CSO control plan and has coordinated with the permitting authority 
the selection of the controls necessary to meet the requirements of the 
CWA, the permitting authority should include in an appropriate 
enforceable mechanism, requirements for implementation of the long-term 
CSO control plan, including conditions for water quality monitoring and 
operation and maintenance.
B. NPDES Permit Requirements
    Following are the major elements of NPDES permits to implement this 
Policy and ensure protection of water quality.
1. Phase I Permits--Requirements for Demonstration of Implementation of 
the Nine Minimum Controls and Development of the Long-Term CSO Control 
Plan
    In the Phase I permit issued/modified to reflect this Policy, the 
NPDES authority should at least require permittees to:
    a. Immediately implement BAT/BCT, which at a minimum includes the 
nine minimum controls, as determined on a BPJ basis by the permitting 
authority;
    b. Develop and submit a report documenting the implementation of 
the nine minimum controls within two years of permit issuance/
modification;
    c. Comply with applicable WQS, no later than the date allowed under 
the State's WQS, expressed in the form of a narrative limitation; and
    d. develop and submit, consistent with this Policy and based on a 
schedule in an appropriate enforceable mechanism, a long-term CSO 
control plan as soon as practicable, but generally within two years 
after the effective date of the permit issuance/ modification. However, 
permitting authorities may establish a longer timetable for completion 
of the long-term CSO control plan on a case-by-case basis to account 
for site-specific factors that may influence the complexity of the 
planning process.
    The NPDES authority should include compliance dates on the fastest 
practicable schedule for each of the nine minimum controls in an 
appropriate enforceable mechanism issued in conjunction with the Phase 
I permit. The use of enforceable orders is necessary unless Congress 
amends the CWA. All orders should require compliance with the nine 
minimum controls no later than January 1, 1997.
2. Phase II Permits--Requirements for Implementation of a Long-Term CSO 
Control Plan
    Once the permittee has completed development of the long-term CSO 
control plan and the selection of the controls necessary to meet CWA 
requirements has been coordinated with the permitting and WQS 
authorities, the permitting authority should include, in an appropriate 
enforceable mechanism, requirements for implementation of the long-term 
CSO control plan as soon as practicable. Where the permittee has 
selected controls based on the ``presumption'' approach described in 
Section II.C.4, the permitting authority must have determined that the 
presumption that such level of treatment will achieve water quality 
standards is reasonable in light of the data and analysis conducted 
under this Policy. The Phase II permit should contain:
    a. Requirements to implement the technology-based controls 
including the nine minimum controls determined on a BPJ basis;
    b. Narrative requirements which insure that the selected CSO 
controls are implemented, operated and maintained as described in the 
long-term CSO control plan;
    c. Water quality-based effluent limits under 40 CFR 122.44(d)(1) 
and 122.44(k), requiring, at a minimum, compliance with, no later than 
the date allowed under the State's WQS, the numeric performance 
standards for the selected CSO controls, based on average design 
conditions specifying at least one of the following:
    i. A maximum number of overflow events per year for specified 
design conditions consistent with II.C.4.a.i; or
    ii. A minimum percentage capture of combined sewage by volume for 
treatment under specified design conditions consistent with 
II.C.4.a.ii; or
    iii. A minimum removal of the mass of pollutants discharged for 
specified design conditions consistent with II.C.4.a.iii; or
    iv. performance standards and requirements that are consistent with 
II.C.4.b. of the Policy.
    d. A requirement to implement, with an established schedule, the 
approved post-construction water quality assessment program including 
requirements to monitor and collect sufficient information to 
demonstrate compliance with WQS and protection of designated uses as 
well as to determine the effectiveness of CSO controls.
    e. A requirement to reassess overflows to sensitive areas in those 
cases where elimination or relocation of the overflows is not 
physically possible and economically achievable. The reassessment 
should be based on consideration of new or improved techniques to 
eliminate or relocate overflows or changed circumstances that influence 
economic achievability;
    f. Conditions establishing requirements for maximizing the 
treatment of wet weather flows at the POTW treatment plant, as 
appropriate, consistent with Section II.C.7. of this Policy;
    g. A reopener clause authorizing the NPDES authority to reopen and 
modify the permit upon determination that the CSO controls fail to meet 
WQS or protect designated uses. Upon such determination, the NPDES 
authority should promptly notify the permittee and proceed to modify or 
reissue the permit. The permittee should be required to develop, submit 
and implement, as soon as practicable, a revised CSO control plan which 
contains additional controls to meet WQS and designated uses. If the 
initial CSO control plan was approved under the demonstration provision 
of Section II.C.4.b., the revised plan, at a minimum, should provide 
for controls that satisfy one of the criteria in Section II.C.4.a. 
unless the permittee demonstrates that the revised plan is clearly 
adequate to meet WQS at a lower cost and it is shown that the 
additional controls resulting from the criteria in Section II.C.4.a. 
will not result in a greater overall improvement in water quality.
    Unless the permittee can comply with all of the requirements of the 
Phase II permit, the NPDES authority should include, in an enforceable 
mechanism, compliance dates on the fastest practicable schedule for 
those activities directly related to meeting the requirements of the 
CWA. For major permittees, the compliance schedule should be placed in 
a judicial order. Proper compliance with the schedule for implementing 
the controls recommended in the long-term CSO control plan constitutes 
compliance with the elements of this Policy concerning planning and 
implementation of a long term CSO remedy.
3. Phasing Considerations
    Implementation of CSO controls may be phased based on the relative 
importance of and adverse impacts upon WQS and designated uses, as well 
as the permittee's financial capability and its previous efforts to 
control CSOs. The NPDES authority should evaluate the proposed 
implementation schedule and construction phasing discussed in Section 
II.C.8. of this Policy. The permit should require compliance with the 
controls proposed in the long-term CSO control plan no later than the 
applicable deadline(s) under the CWA or State law. If compliance with 
the Phase II permit is not possible, an enforceable schedule, 
consistent with the Enforcement and Compliance Section of this Policy, 
should be issued in conjunction with the Phase II permit which 
specifies the schedule and milestones for implementation of the long-
term CSO control plan.

V. Enforcement and Compliance

A. Overview
    It is important that permittees act immediately to take the 
necessary steps to comply with the CWA. The CSO enforcement effort will 
commence with an initiative to address CSOs that discharge during dry 
weather, followed by an enforcement effort in conjunction with 
permitting CSOs discussed earlier in this Policy. Success of the 
enforcement effort will depend in large part upon expeditious action by 
NPDES authorities in issuing enforceable permits that include 
requirements both for the nine minimum controls and for compliance with 
all other requirements of the CWA. Priority for enforcement actions 
should be set based on environmental impacts or sensitive areas 
affected by CSOs.
    As a further inducement for permittees to cooperate with this 
process, EPA is prepared to exercise its enforcement discretion in 
determining whether or not to seek civil penalties for past CSO 
violations if permittees meet the objectives and schedules of this 
Policy and do not have CSOs during dry weather.
B. Enforcement of CSO Dry Weather Discharge Prohibition
    EPA intends to commence immediately an enforcement initiative 
against CSO permittees which have CWA violations due to CSOs during dry 
weather. Discharges during dry weather have always been prohibited by 
the NPDES program. Such discharges can create serious public health and 
water quality problems. EPA will use its CWA Section 308 monitoring, 
reporting, and inspection authorities, together with NPDES State 
authorities, to locate these violations, and to determine their causes. 
Appropriate remedies and penalties will be sought for CSOs during dry 
weather. EPA will provide NPDES authorities more specific guidance on 
this enforcement initiative separately.
C. Enforcement of Wet Weather CSO Requirements
    Under the CWA, EPA can use several enforcement options to address 
permittees with CSOs. Those options directly applicable to this Policy 
are section 308 Information Requests, section 309(a) Administrative 
Orders, section 309(g) Administrative Penalty Orders, section 309 (b) 
and (d) Civil Judicial Actions, and section 504 Emergency Powers. NPDES 
States should use comparable means.
    NPDES authorities should set priorities for enforcement based on 
environmental impacts or sensitive areas affected by CSOs. Permittees 
that have voluntarily initiated monitoring and are progressing 
expeditiously toward appropriate CSO controls should be given due 
consideration for their efforts.
1. Enforcement for Compliance With Phase I Permits
    Enforcement for compliance with Phase I permits will focus on 
requirements to implement at least the nine minimum controls, and 
develop the long-term CSO control plan leading to compliance with the 
requirements of the CWA. Where immediate compliance with the Phase I 
permit is infeasible, the NPDES authority should issue an enforceable 
schedule, in concert with the Phase I permit, requiring compliance with 
the CWA and imposing compliance schedules with dates for each of the 
nine minimum controls as soon as practicable. All enforcement 
authorities should require compliance with the nine minimum controls no 
later than January 1, 1997. Where the NPDES authority is issuing an 
order with a compliance schedule for the nine minimum controls, this 
order should also include a schedule for development of the long-term 
CSO control plan.
    If a CSO permittee fails to meet the final compliance date of the 
schedule, the NPDES authority should initiate appropriate judicial 
action.
2. Enforcement for Compliance With Phase II Permits
    The main focus for enforcing compliance with Phase II permits will 
be to incorporate the long-term CSO control plan through a civil 
judicial action, an administrative order, or other enforceable 
mechanism requiring compliance with the CWA and imposing a compliance 
schedule with appropriate milestone dates necessary to implement the 
plan.
    In general, a judicial order is the appropriate mechanism for 
incorporating the above provisions for Phase II. Administrative orders, 
however, may be appropriate for permittees whose long-term control 
plans will take less than five years to complete, and for minors that 
have complied with the final date of the enforceable order for 
compliance with their Phase I permit. If necessary, any of the nine 
minimum controls that have not been implemented by this time should be 
included in the terms of the judicial order.
D. Penalties
    EPA is prepared not to seek civil penalties for past CSO 
violations, if permittees have no discharges during dry weather and 
meet the objectives and schedules of this Policy. Notwithstanding this, 
where a permittee has other significant CWA violations for which EPA or 
the State is taking judicial action, penalties may be considered as 
part of that action for the following:
    1. CSOs during dry weather;
    2. Violations of CSO-related requirements in NPDES permits; consent 
decrees or court orders which predate this policy; or
    3. Other CWA violations.
    EPA will not seek penalties for past CSO violations from permittees 
that fully comply with the Phase I permit or enforceable order 
requiring compliance with the Phase I permit. For permittees that fail 
to comply, EPA will exercise its enforcement discretion in determining 
whether to seek penalties for the time period for which the compliance 
schedule was violated. If the milestone dates of the enforceable 
schedule are not achieved and penalties are sought, penalties should be 
calculated from the last milestone date that was met.
    At the time of the judicial settlement imposing a compliance 
schedule implementing the Phase II permit requirements, EPA will not 
seek penalties for past CSO violations from permittees that fully 
comply with the enforceable order requiring compliance with the Phase I 
permit and if the terms of the judicial order are expeditiously agreed 
to on consent. However, stipulated penalties for violation of the 
judicial order generally should be included in the order, consistent 
with existing Agency policies. Additional guidance on stipulated 
penalties concerning long-term CSO controls and attainment of WQS will 
be issued.

Paperwork Reduction Act

    The information collection requirements in this policy have been 
approved by the Office of Management and Budget (OMB) under the 
Paperwork Reduction Act, 44 U.S.C. 3501 et seq and have been assigned 
OMB control number 2040-0170.
    This collection of information has an estimated reporting burden 
averaging 578 hours per response and an estimated annual recordkeeping 
burden averaging 25 hours per recordkeeper. These estimates include 
time for reviewing instructions, searching existing data sources, 
gathering and maintaining the data needed, and completing and reviewing 
the collection of information.
    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; EPA; 401 M Street SW. (Mail 
Code 2136); Washington, DC 20460; and to the Office of Information and 
Regulatory Affairs, Office of Management and Budget, Washington, DC 
20503, marked ``Attention: Desk Officer for EPA.''

[FR Doc. 94-9295 Filed 4-18-94; 8:45 am]
BILLING CODE 6560-50-P