Databases and Tools
governments are responsible for designing, planning, constructing, financing,
operating and maintaining wastewater treatment facilities, and their conveyance
systems, known as publicly owned treatment works (POTWs), in compliance
Water Act (CWA) regulations. POTWs collect wastewater
from homes, commercial buildings and industrial facilities and transport it via
a series of pipes, known as a collection system, to the treatment plant. Here,
the POTW removes harmful organisms and other contaminants from the sewage, so
it can be discharged safely into the receiving waters.
POTWs are designed to treat domestic sewage only, but they also receive
wastewater from industrial users. EPA’s General Pretreatment Regulations
establish responsibilities of federal, state and local government, industry and
the public to implement Pretreatment
Standards. The Standards aim to control pollutants originating with industrial
users which may pass through or interfere with POTW treatment processes or
which may contaminate sewage sludge.
systems that were designed to carry stormwater as well as sewage (combined
systems) can also raise compliance issues when, during and after wet weather
events, they exceed the conveyance and treatment capacity of the POTW and
result in untreated discharges (combined sewer overflows, or ’CSOs’).
collection and treatment activities that have compliance obligations include
laboratory operations, biosolids management and disposal, chemical
storage/hazardous materials management and vehicle/equipment management.
U.S. EPA CWA NPDES Program
EPA administers the CWA programs with which local
government must comply. Under the CWA, a permit is needed to discharge a
pollutant from a point source, such as a POTW, into the waters of the United
States. CWA implementation is primarily carried out by states and
several tribes under
authority. EPA retains direct regulatory authority in a few
states, all U.S. territories, and much of Indian Country. Implementation
includes issuing NPDES permits to owners/operators of POTWs.
Permittees must comply with their designated discharge
limitations and submit ’discharge monitoring reports’ (DMRs) showing their
compliance with permit conditions. EPA establishes primary and secondary
treatment standards, which are minimum, technology-based
requirements for municipal wastewater treatment plants.
Permittees must also prevent unauthorized discharges,
such as sanitary sewer overflows (SSOs) and CSOs. This includes implementation
of control strategies and, in the case of CSOs, long-term control plans.
Sewer Overflows and Prevention
Most collection systems constructed since the 1950s use
dedicated sanitary sewers. However, these sometimes suffer from infiltration
and inflow (I/I) of stormwater or groundwater, often during wet weather events. Large
volumes of I/I can cause sanitary sewer overflows and operational problems at
the wastewater treatment facility serving the collection system. Sewage
overflows can be caused by other
problems such as blockages, equipment failures, broken pipes or
SSOs that reach waters of the U.S. are considered
point source discharges. This means SSOs
are prohibited unless authorized by a NPDES permit. Under
the Supreme Court’s recent decision in County of Maui v. Hawaii Wildlife
Fund (’Maui decision’), SSOs that are discharged to groundwater and
conveyed to waters of the U.S. may
also constitute violations. Moreover,
SSOs, including those that do not reach waters of the U.S., may indicate that
sewer systems are being improperly operated or maintained and may violate NPDES
SSOs can be prevented or controlled by
following facility and operational best practices, including:
Sewer system cleaning and
Reducing infiltration and
inflow through system rehabilitation and repairing broken or leaking service
Enlarging or upgrading sewer,
pump station or sewage treatment plant capacity and/or reliability
Limiting fats, oils and
grease (FOG) into the sewer systems
Construction of wet weather
Expanding the capacity of the
Combined Sewer Overflows
CSOs convey untreated or partially treated
human and industrial waste, toxic materials and stormwater. EPA has prescribed
nine minimum controls for operators of CSSs to implement. Permittees must prepare
and implement a long-term control plan to eliminate the CSO and meet water
quality standards. The nine
minimum controls are:
operation and regular maintenance programs for the sewer system and CSO
- Maximum use
of the collection system for storage
- Review and
modification of pretreatment requirements to ensure that CSO impacts are
of flow to the POTW for treatment
of CSOs during dry weather
- Control of
solid and floatable materials in CSOs
prevention programs to reduce contaminants in CSOs
notification to ensure that the public receives adequate notification of CSO
occurrences and CSO impacts
- Monitoring to
effectively characterize CSO impacts and the efficacy of CSO controls.
apply to management of biosolids, a byproduct of wastewater
treatment. Section 405(d) of the CWA requires EPA to establish numeric limits
and management practices that protect public health and the environment from
the reasonably anticipated adverse effects of chemical and microbial pollutants
during the use or disposal of sewage sludge. EPA also reviews biosolids
regulations every two years to identify any additional pollutants that may
occur and establishes regulations for those pollutants that prove harmful to
human health or the environment.
oversees implementation of these programs and may take direct enforcement
action even in states and tribes that have received approval to operate these
permit programs. EPA and the U.S. Department of Justice have brought
enforcement actions against cities and municipal POTWs, entering into consent
decrees (agreements filed with federal courts) with the municipalities to
ensure correction of violations and investment of funds.
EPA’s Office of Wastewater
Management (OWM) oversees programs protecting the nation's
waters and watersheds. Its mission focuses on control of water and wastewater that
is collected in discrete conveyances (also called point sources), including
pipes, ditches and sanitary or storm sewers. OWM is home to the Clean Water
State Revolving Fund, focused
on providing low-cost financing for local wastewater treatment systems,
nonpoint source projects and estuary protection through support of state
revolving funds. OWM also administers the Water Infrastructure Finance and
Act (WIFIA) program established in 2014, a federal loan program
for water and wastewater infrastructure projects.
website offers a substantial set of resources, rulemakings and guidance
documents helpful for local governments. ’
Municipal Wastewater Portal. Information
on municipal wastewater management and treatment, permitting, financing, reporting
Enforcement Policy, Guidance and Publications. Comprehensive
collection of EPA guidance documents on enforcement of the CWA and Safe
Drinking Water Act.
Methods Update Rule. Identifies methods used by municipalities
and industries and their laboratories to analyze the chemical, physical and
biological components of wastewater, identify pollutants, satisfy reporting
requirements and document compliance with applicable requirements.
Strategy for Per- and Polyfluoroalkyl Substances (PFAS) in Federally Issued
NPDES Permits. Recommended actions for implementing EPA's interim PFAS
strategy. Listed actions focus on adapting NPDES permitting practices to
increase monitoring for PFAS in NPDES permitted facilities. Also details EPA's
future plans to promulgate information-sharing on PFAS monitoring between
Methods for PFAS. Information on EPA's development of
analytical methods to test for PFAS in wastewater, groundwater and surface
Standards & Limits. Program
requirements for pretreatment of industrial wastes and related requirements.
Guidance Memorandum. Guidance
to the regulated community and permitting authorities on the impact of the
Supreme Court's Maui decision on the CWA Section 402 NPDES permit program.
Outlines seven non-exclusive factors to evaluate whether a point source
pollutant discharge that travels through groundwater can be treated as the
equivalent of a direct discharge to Waters of the United States.
Regulations Resource Locator. Find environmental regulations,
link to state agencies, retrieve agency news and download sector-specific resources.
The Water Environment
Federation (WEF). International not-for-profit educational and technical
organization of over 40,000 water experts. Provides webinars, technical
assistance trainings and guidance documents on wastewater system management.
Association of Clean Water
Administrators (ACWA). National
association of the state, interstate and territorial regulators administering
water pollution control and clean water programs.
National Association of Clean Water Agencies
(NACWA). National association of public wastewater and stormwater
agencies and utility districts.
Making Water a
of Choice: Water Workforce Case Studies. Nine
case studies of communities in the U.S. and their unique initiatives to improve
recruitment and retention of water and wastewater professionals. Strategies
include increased outreach to youths and minority communities and development
of leadership training programs.
Sustainable Workforce: Decentralized/Onsite Wastewater Occupations. Report
on occupational characteristics, growth projections and basic education and
training requirements for professionals working in the decentralized wastewater
Hot and Getting
Hotter: A Report for Utilities on Heat Impacts.
Projects heat impacts on utility personnel and assets through the year 2070 and
provides adaptation procedures to reduce heat-related harm to outside utility
workers and infrastructure including HVAC systems, water treatment plants,
pumps and motors.
Systems Guidebook to Sustainable Water and Wastewater Utility Management. Walks
small system operators through best practices in 10 key areas of sustainable
system management (Product Quality, Customer Satisfaction, Employee &
Leadership Development, Operational Optimization, Financial Viability,
Infrastructure Stability, Operational Resiliency, Community Sustainability
& Economic Development, Water Resource Adequacy, and Stakeholder
Understanding & Support). Provides further guidance on conducting system
assessments and identifying priority areas for improvement. Information on
conducting workshops and trainings on this manual is available in EPA's
companion publication, "Workshop
in a Box:
Sustainable Management of Rural and Small Water and Wastewater Systems
Choices for Your Utility: Using Sustainability Criteria for Water
Infrastructure Decision Making. Provides water and wastewater
utilities with a six-step process to compare and choose between competing
infrastructure alternatives. The process highlights considerations, including
the creation of sustainability and performance goals and the determination of
common and relevant evaluation criteria, to ensure that a municipality's
selected infrastructure will meet its regulatory requirements.
Municipal Utilities Authority: A Wet Weather Case Study of Incorporating
Community Interests into Effective Infrastructure Decision-Making. Camden
County, New Jersey case study on successful integration of community
stakeholder involvement, long-term sustainability considerations and cost
effectiveness into the preparation of a Long Term Control Plan to address CSO.
Case Studies on
Implementing Low-Cost Modifications to Improve Nutrient Reduction at Wastewater
Treatment Plants. Empirical data and
experiences of non-advanced wastewater treatment plants that have improved
their nutrient reduction capabilities with low-cost techniques and no costly
Limits Development Guidance. Assistance for municipalities
that own or operate publicly owned treatment works (POTWs) on developing and
implementing local pretreatment programs.
Clearinghouse. Information-sharing platform focused on cost-effectiveness and
performance, separated into databases on centralized and decentralized treatment
systems. Provides reports, case studies and webinars.
For more information on available funding and
financing strategies, please visit the "Wastewater and
Stormwater" section of our Financing page.