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
- MS4 General Permit
- MS4 Annual Report
- Minneapolis 2011 Phase I Permit
- Minneapolis 2018 Phase I Permit
- St Paul 2011 Phase I Permit
MS4 General Permit reissuance
Visit the MS4 General Permit reissuance page for updates on the next MS4 General Permit.
Minimum Control Measures
In order to operate an effective Stormwater Pollution Prevention Program (SWPPP), there are six different components known as Minimum Control Measures (MCMs) that must be incorporated into the SWPPP.
- MCM 1 Public Education and Outreach - Public education outreach materials, public education implementation plan, examples of how to document outreach activities, and examples of outreach materials.
- MCM 2 Public Participation/Involvement - Examples of how to document events held.
- MCM 3 Illicit Discharge Detection and Elimination - Regulatory mechanism to prohibit illicit discharges, illicit discharge recognition training, procedures for investigating, locating, and eliminating the source of illicit discharges, and spill response procedures.
- MCM 4 Construction Site Stormwater Control - Site plan review procedures & items to evaluate, construction site inspection procedures and inspection checklists, and documentation of site plan reviews.
- MCM 5 Post-Construction Stormwater Management - Legal mechanisms for long-term maintenance of structural stormwater best management practices (BMPs), site plan review checklists.
- MCM 6 Pollution Prevention/Good Housekeeping - Facilities inventory examples; procedures for determining pond effectiveness of treating total suspended solids (TSS) and total phosphorus (TP); inspection checklists for documenting structural stormwater BMPs, stormwater management ponds, outfalls, stockpiles, and storage and material handling areas; employee training commensurate with the employee's job responsibilities.
MS4 toolkit
The municipal separate storm sewer system (MS4) toolkit is 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.
MS4 Digital Document Library
The MS4 Digital Document Library 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). Common examples of documents in the library include:
- inspection and checklists and forms
- site plan review checklists
- documentation tracking mechanisms
- standard operating procedures
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.
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)
- 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
Other technical assistance and guidance
- MS4 staff contact information and staff assignments
- MS4 mapping tool is 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 case studies
- MS4 webinars and videos
- MPCA MS4 website - additional guidance documents and fact sheets
- Pollution prevention guidance
- Stormwater and Wetlands - Planning and Evaluation Guidelines
- Untreated Stormwater Runoff to Lakes, Streams, and Wetlands
- 2017 MS4 Technical Assistance and Outreach Needs Survey Results
- Pond, lake, and wetland inventory