Information: We recently updated this page and will continue to work on information about MS4 stormwater management. If you have suggestions, we welcome comments using the comment box at the bottom of most pages in the manual.
Information: NOTE: Minnesota uses the term Stormwater Pollution Prevention Program (SWPPP) for MS4 stormwater, while several states and EPA may use the term Stormwater Management Plan (SWMP). These terms refer to the same thing.
icon for MS4 stormwater

The municipal separate storm sewer system (MS4) stormwater program is designed to reduce the amount of sediment and pollution that enters surface and ground water from storm sewer systems. Public entities that own or operate an MS4 play a key role in preventing or reducing the negative impacts stormwater runoff has on our valuable water resources.

Proper stormwater runoff management in urbanized areas is especially important for restoring and protecting surface waters. Urbanized areas are more likely to have activities that contribute pollutants to stormwater runoff, like applying anti/deicing mixtures to roads; fueling vehicles; grease, oil, and other spills; landscaping; and using pesticides and fertilizers. Urbanized areas have a large amount of impervious surfaces, or surfaces that rain and snowmelt cannot pass through, such as streets, driveways, rooftops, parking lots and sidewalks. Stormwater runoff from these surfaces travels faster and in higher amounts, damaging rivers, streams, and wetlands; destroying aquatic habitats; increasing the amount of pollutants that enter surface waters; and limiting groundwater recharge and the MS4 program is to help mitigate the impact.

Background Information

Regulated MS4 permittees are required to develop a stormwater pollution prevention program (SWPPP) to reduce the pollutants entering the municipality's storm sewer system. When applying for the MS4 permit, permittees identified measurable goals they intended their SWPPP to reach. Based on these goals, permittees should evaluate the effectiveness of their program and make any necessary changes.

2020 MS4 General Permit

MS4 Stormwater Permits (Individual)

Previous Permits

Minimum Control Measures

When seeking to manage a Municipal Storm Sewer System (MS4), an effective Stormwater Pollution Prevention Program (SWPPP) has six different components known as Minimum Control Measures (MCMs).

Total Maximum Daily Loads (TMDLs)

Total Maximum Daily Loads (TMDLs) are EPA approved amounts of pollutant loading that can occur and have a water body meet water quality standards. Follow this link to learn more about them along with guidance and resources.

Tools and Resources

MS4 Audit Guidance

The U.S. Environmental Protection Agency (EPA) mandates the Minnesota Pollution Control Agency (MPCA) to evaluate MS4 permittees for compliance with the MS4 General Permit. The MPCA does this through compliance audits. To find out more information about the audit process see the pages below:

MPCA MS4 Technical Assistance

Other Resources and Documents

This page was last edited on 22 July 2024, at 18:37.