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.

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.

Specific NPDES permit requirements for MS4s can be found through the links provided below:

• NPDES Permit Requirements for MEDIUM and LARGE MS4s
• NPDES Permit Requirements for Regulated SMALL MS4s

The following fact sheets were developed by EPA Region III to assist municipalities in understanding issues critical to the implementation of their stormwater program.

• Evaluating the Effectiveness of Municipal Stormwater Programs [PDF - 350 KB - 6 pp]
• Funding Stormwater Programs [PDF - 355 KB - 5 pp]
• Incorporating Environmentally Sensitive Development Into Municipal Stormwater Programs [PDF - 432 KB - 7 pp]
• Understanding Impaired Waters and Total Maximum Daily Load (TMDL) Requirements for Municipal Stormwater Programs [PDF - 620 KB - 5 pp]

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. The tool 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.

Reducing Stormwater Costs through Low Impact Development (LID) Strategies and Practices - This EPA developed report contains 17 case studies from developments across North America that examines the economic viability of LID practices compared to traditional stormwater management design practices. It also highlights examples, where LID practices were shown to be both fiscally and environmentally beneficial to communities by reducing project costs and improving environmental performance.

Guidance for Municipal Stormwater Funding [PDF - 1 MB - 140 pp] - This guidance was developed by the National Association of Flood and Stormwater Management Agencies (NAFSMA) under a grant provided by the Environmental Protection Agency in January 2006.

Municipal Separate Storm Sewer System (MS4) Program Evaluation Guidance - The MS4 Evaluation Guide is primarily for use by NPDES authorities to evaluate the quality of Phase I and Phase II MS4 programs, for permit compliance, technical assistance, and other purposes. It can be used for comprehensive program evaluations, or for certain components. It can also be used by MS4 program managers to evaluate their own programs.

New and Revised National Menu of Stormwater BMPs - EPA has completed a significant revision of the National Menu of Best Management Practices (BMPs). The new menu will be easier to browse and search and includes approximately 20 new fact sheets that highlight innovative practices. We also invite knowledgeable experts in the stormwater field to provide comments and supply additional information that can improve the fact sheets contained in the Menu.

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Last updated on March 18, 2008 1:59 PM
URL:http://cfpub1.epa.gov/npdes/stormwater/munic.cfm