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Issue Summary
Organizations/Non-Government Programs
Databases and Tools
Financial Assistance


Issue SummaryStormwater

When rain water runs off the sides of buildings, and over parking lots and other impervious urban areas, it picks up and transports pollutants. In times of heavy rainfall, sanitary sewer systems may not have the capacity to hold all the water entering the system, which results in sanitary sewer overflows (SSOs), and combined sewer overflows (CSOs).

These events often result in the discharge of sewage and pollutants to nearby surface waters. However, many local governments may lack the financial and technical resources necessary to address these issues. The resulting noncompliance with regulations designed to address wet weather pollution can further increase the burden on these local governments.

Under the NPDES stormwater program, operators of large, medium and regulated small municipal separate storm sewer systems (MS4s) require authorization to discharge pollutants. Medium and large MS4 operators are required to submit comprehensive permit applications and are issued individual permits. Regulated small MS4 operators have the option of choosing to be covered by an individual permit, a general permit, or a modification of an existing Phase I MS4's individual permit.

Local governments involved in construction projects will also need to comply with stormwater construction rules. Stormwater runoff from construction activities can have a significant impact on water quality by contributing sediment and other pollutants to creeks, streams, lakes, etc. Under the Federal Clean Water Act, The National Pollutant Discharge Elimination System (NPDES) permit program controls water pollution by regulating sources of pollution that discharge into waters of the United States. Federal regulations relating to the NPDES Stormwater Permit Program require operators of certain sized construction projects to obtain authorization to discharge stormwater under an National Pollutant Discharge Elimination System (NPDES) construction stormwater permit. Under Phase II Stormwater regulations, which became effective March 2003, required construction activities that disturbed one or more acres of land to obtain NPDES permit coverage.

Although stormwater regulations are federal rules, they are implemented by state environmental agencies (except for Massachusetts, New Mexico, Alaska, Idaho and New Hampshire where EPA retains authority).

The following material provides information on various technical and financial resources available to local governments, as well as information on current wet weather regulatory and legislative initiatives, workshops, web sites, and publications which can assist local governments in reducing wet weather pollution.


Guidance Memorandum. Provides guidance to the regulated community and permitting authorities on the impact of the Supreme Court's decision of County of Maui v. Hawaii Wildlife Fund on CWA Section 402 National Pollutant Discharge Elimination System (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 in the context of the existing NPDES framework.

NPDES Training Courses and Workshops. The NPDES Permitting program offers training courses, workshops, and webcasts to explain the regulatory framework and technical considerations of the NPDES Permit program.

Stormwater Discharges From Municipal Separate Storm Sewer Systems (MS4s). Under the NPDES stormwater program, operators of large, medium and regulated small municipal separate storm sewer systems (MS4s) require authorization to discharge pollutants under an NPDES permit.

Stormwater Discharges from Construction Activities. The NPDES Stormwater program requires operators of construction sites one acre or larger (including smaller sites that are part of a larger common plan of development) to obtain authorization to discharge stormwater under an NPDES construction stormwater permit.

Environmental Finance Center Integrated Planning for Municipal Stormwater and Wastewater. Provides recordings of past workshops, access to future events, opportunities for peer-to-peer exchange and other guidance on Element 4 of the EPA's integrated planning process.


Construction Stormwater Resource Locator. This resource is designed to help with questions regarding stormwater permits and other requirements.

Organizations/Non-Government Programs

United States Geological Survey (USGS) National Water Dashboard. Interactive mapping tool that utilizes the USGS database of water data. Users can see the full range of water quality data and other information available on their local lakes, wells, and streams in real time.

Innovative Partnership to Assist Rural Communities to Improve the Health of Their Communities. The Appalachian Coal Country Team and Western Hardrock Watershed Team, or the OSM/VISTA Teams, assist rural communities impoverished by environmental degradation and its consequences to make their home-place watersheds healthier places to live and work.

Green Infrastructure Valuation Guide. A new report by the Center for Neighborhood Technology and American Rivers quantifies the economic value of green infrastructure. This tool is meant to help municipalities adopt cost-effective stormwater management techniques.

National Association of Flood & Stormwater Management Agencies (NAFSMA). An organization of public agencies whose function is the protection of lives, property and economic activity from the adverse impacts of storm and flood waters.

Urban Stormwater Management in the United States. On October 15, 2008, the National Research Council Water Sciences and Technology Board released the report Urban Stormwater Management in the United States (Committee on Reducing Stormwater Discharge Contributions to Water Pollution, National Research Council, National Academies Press). The report is the product of a 2-year process undertaken by the 15-member committee. The 513 page report provides a description of the history of stormwater management in the United States; an overview of stormwater regulations and the federal regulatory program; and information on a number of relevant scientific and technological issues such as hydrology, geomorphology, biology, monitoring and modeling. The report also provides a number of significant findings and recommendations on how stormwater management in the United States should be improved to achieve better environmental outcomes. A Report in Brief fact sheet is also available.

Guidance for Nine Minimum CSO Controls. This publication provides information on nine minimum technology-based controls that communities are expected to use to address CSO problems, without extensive engineering studies or significant construction costs, before long-term measures are taken.

Guidance for Long-Term CSO Control Plan. This publication describes how local governments can develop comprehensive long-term CSO control plans that recognize the site-specific nature of CSOs and their impacts on receiving water bodies.

National Menu of Best Management Practices for NPDES Storm Water Phase II. This Environmental Protection Agency publication contains 112 fact sheets that describe BMPs that can be used to fulfill the 6 minimum measures described in the Storm Water Phase II Rule.

Storm Water Phase II Compliance Assistance Guide. This Environmental Protection Agency Publication seeks to aid regulated entities in complying with the Storm Water Phase II final rule.

Storm Water Strategies: Community Responses to Runoff Pollution. This Natural Resources Defense Council report documents some of the most effective strategies being employed by local governments around the country to control urban runoff pollution.

Economic Benefits Of Runoff Controls. This Environmental Protection Agency report discusses two types of structural controls that have been documented as providing economic benefits: urban runoff ponds and constructed wetlands.

Sanitary Sewer Overflow (SSO) Fact Sheet. This Environmental Protection Agency fact sheet explains what SSOs are, why they occur, what health risks they pose, and how they can be prevented.


Making Water a Career of Choice: Water Workforce Case Studies. Includes nine case studies of communities in the U.S. and their unique initiatives to improve recruitment and retention of water and wastewater professionals. Strategies explained include increased outreach to youths and minority communities and development of leadership training programs.

Databases and Tools

Urban BMP Performance Tool - This tool has been developed to provide stormwater professionals with easy access to approximately 220 studies assessing the performance of over 275 BMPs. It provides access to studies covering a variety of traditional and low impact BMP types, including retention and detention ponds, biofilters, grassed filter strips, porous pavement, wetlands, and others. Users will also find a series of essays aimed at improving understanding of BMP performance and the importance of volume reduction/infiltration in these assessments.

NPDES Compliance Monitoring Strategy - This strategy, which takes effect in 2009, outlines inspection and compliance goals for the entire NPDES program, including major and minor NPDES facilities, pretreatment programs, biosolids, CSOs, SSOs, stormwater, and CAFOs. It places increased emphasis on wet weather issues, particularly stormwater sources, and sets ambitious targets for audits and inspections of Phase I and II MS4s, construction sites, and industrial facilities.

National Storm Water Best Management Practices Database. This searchable database provides access to BMP performance data in a standardized format for over 113 BMP studies conducted over the past fifteen years.

Community-enabled Lifecycle Analysis of Stormwater Infrastructure Costs (CLASIC). Interactive online tool that assesses lifecycle costs, performance and co-benefits of green, hybrid green-gray and gray infrastructure options. Allows users to combine different options to create various scenarios and review their associated costs and benefits.

Adapting Stormwater Management for Coastal Floods. Step-by-step guidance for developing climate-resilient, flood-prepared stormwater infrastructure by understanding, assessing and analyzing your current system and local flood projections.

Financial Assistance

Guidance for Combined Sewer Overflow Funding Options. This document describes the options that may be available to fund the capital, debt service, and operational costs of CSO controls.