Stormwater Program for Municipal Separate Storm Sewer Systems (MS4)
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.
- What is a municipal separate storm sewer system (MS4)?
- Why is a municipality regulated under the MS4 permit?
Contents
MS4 stormwater permit
- 2013 MS4 General Permit
- MS4 Annual Report
- Minneapolis 2011 Phase I Permit
- Minneapolis 2018 Phase I Permit
- St Paul 2011 Phase I Permit
- 2018 St. Paul Phase 1 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):
- MCM 1 Public Education and Outreach
- MCM 2 Public Participation/Involvement
- MCM 3 Illicit Discharge Detection and Elimination
- MCM 4 Construction Site Stormwater Control
- MCM 5 Post-Construction Stormwater Management
- MCM 6 Pollution Prevention/Good Housekeeping
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 and photos/graphics, 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 MPCA reviewed and available for anyone to download and use.
An interactive online map tool that can be used to view and explore Minnesota MS4 boundaries, defined urbanized areas, impaired waters, outstanding resource value waters, trout waters and approved TMDL study areas.
A collection of links to a variety of Minnesota Stormwater Manual fact sheets on stormwater pollution prevention methods within MS4s.
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)
- Total Maximum Daily Loads (TMDLs)
- TMDL Overview
- Summary of TMDL requirements in stormwater permits
- Forms and guidance for TMDLs
- Summary of data received from permittees on MS4 TMDL permit reporting forms
- Visit the MPCA TMDL Project page for information on specific projects across the state