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.
icon for MS4 stormwater
MPCA MS4 staff contact information can be found at this link.

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.

MS4 stormwater permit

MS4 General Permit reissuance 2019

Visit the MS4 General Permit reissuance page for updates on the next MS4 General Permit.

Minimum Control Measures

An effective Stormwater Pollution Prevention Program (SWPPP) has six different components known as Minimum Control Measures (MCMs):

Tools and resources

A collection of resources for use by stormwater program staff. It is intended to help entities regulated under the MS4 program meet the requirements of the general permit. It offers a wide range of downloadable stormwater education information including sample fact sheets, newsletters, videos, and other resources.

Provides guidance to help local MS4 staff meet the requirements of the six Minimum Control Measures (MCMs) in the MS4 General Permit and assist with overall stormwater management. In addition to general guidance documents, the Digital Document Library has example documents that stormwater staff are using to manage their stormwater pollution prevention programs (SWPPPs). All documents in the Digital Document Library are available for all site users to download and use. MPCA staff will review all materials to ensure their compliance with the MS4 General Permit prior to posting in the Digital Document Library.

An interactive online map tool that can be used to view and explore MS4 boundaries, defined urban areas, impaired waters, outstanding resource value waters, trout waters and approved TMDL study areas.

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:

Total Maximum Daily Loads (TMDLs)

Other technical assistance and guidance