Stormwater Program for Municipal Separate Storm Sewer Systems (MS4)
Program update — What's new
- The MPCA will go to the MPCA Citizens Board for a decision on the draft MS4 permit on May 21, 2013. See the MS4 General Permit page for an updated status.
- Guidance is now available on the MPCA web site for MS4 permittees and other municipalities specific to stormwater sediment removal best management practices. The new guidance and publication is titled “Managing Stormwater Sediment Best Management Practice Guidance for Municipalities” and it is located on the main Stormwater page.
- The MPCA grant funds to assist municipalities with removing contaminated sediment from stormwater ponds has been exhausted. There are no grant funds remaining. For more information, see Restriction on Coal Tar-Based Sealants.
According to the 1996 National Water Quality Inventory, stormwater runoff is a leading source of water pollution. Stormwater runoff can harm surface waters such as rivers, lakes, and streams which in turn cause or contribute to water quality standards being exceeded.
Stormwater runoff can change natural hydrologic patterns, accelerate stream flows, destroy aquatic habitats, and elevate pollutant concentrations and loadings. Development substantially increases impervious surfaces thereby increasing runoff from city streets, driveways, parking lots, and sidewalks, on which pollutants from human activities settle.
Common pollutants in runoff include pesticides, fertilizers, oils, metals, pathogens, salt, sediment, litter and other debris are transported via stormwater and discharged - untreated - to water resources through storm sewer systems.
The Stormwater Program for MS4s is designed to reduce the amount of sediment and pollution that enters surface and ground water from storm sewer systems to the maximum extent practicable. Stormwater discharges associated with MS4s are regulated through the use of National Pollutant Discharge Elimination System (NPDES) permits. NPDES permits are legal documents. Through this permit, the owner or operator is required to develop a stormwater pollution prevention program (SWPPP) that incorporates best management practices (BMPs) applicable to their MS4. See the following fact sheet for additional information:
A municipal separate storm sewer system is a conveyance or system of conveyances (roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, storm drains):
- Owned or operated by a state, city, town, borough, county, parish, district, association, or other public body (created by or pursuant to State law) having jurisdiction over disposal of sewage, industrial wastes, stormwater, or other wastes, including special districts under State law such as a sewer district, flood control district or drainage districts, or similar entity, or an Indian tribe or an authorized Indian tribal organization, or a designated and approved management agency under section 208 of the Clean Water Act that discharges to waters of the United States;
- Designed or used for collecting or conveying stormwater;
- Which is not a combined sewer; and
- Which is not part of a publicly owned treatment works.
There are three categories of regulated small MS4s: mandatory, designated and petition. Small MS4s include municipalities, townships, counties, military bases, hospitals, prison complexes, highway departments, and universities.
- Mandatory MS4s: MS4s in urbanized areas as defined by the 2000 Census are required to obtain a NPDES/SDS stormwater permit. An "urbanized area" is defined as a land area comprising one or more places (“central places”) and the adjacent densely settled surrounding area (“urban fringe”) that together have a residential population of at least 50,000 and a density of at least 1,000 people per square mile. The definition also includes any other public storm sewer system located fully or partially within an urbanized area.
The following list identifies Minnesota’s mandatory small MS4 cities, townships, and counties. The list also includes non-traditional mandatory MS4s identified by MPCA staff as requiring permit coverage. Non-traditional MS4s are publicly owned systems at military bases, hospitals, prisons, universities, highways and other thoroughfares.
Note: The cities of Minneapolis and St. Paul received individual stormwater permits in 2000.
- Designated MS4s: MS4s outside of urbanized areas that have been designated by the MPCA for permit coverage under Minn. R. ch 7090 are required to obtain a NPDES/SDS stormwater permit. MS4s designated by rule are cities and townships with a population of at least 10,000; and cities and townships with a population of at least 5,000 and discharging or the potential to discharge to valuable or polluted waters. These designated MS4s are required to obtain permit coverage by February 15, 2007.
The rules also establish criteria that can be applied to designate future MS4s under a designation process identified in the rule. Visit the Stormwater Program Rulemaking Web page for details.
- Petition MS4s: MS4s that are designated through the petition process under Minn. R. ch. 7090 are required to obtain a NPDES/SDS stormwater permit. The public can petition the Commissioner for the designation of an MS4 based on the designation criteria established in the rules. Visit the Stormwater Program Rulemaking Web page for details.
- MS4 mapping tool: This is an electronic map tool using Geographic Information Systems (GIS) technology.
Note: This is best viewed using Internet Explorer 5.0 or higher or Netscape 6.0 or higher, with pop-up blockers disabled and screen resolution set to 1024x768 or higher.
- Duluth Area
- Fargo/Moorhead Area
- Grand Forks Area
- La Crosse/La Crescent Area
- Minneapolis/St. Paul Area
- Rochester Area
- St. Cloud Area
Note: The maps above for Duluth, Minneapolis/St. Paul and St. Cloud areas are interactive. Once you've opened one of those maps, click on a numbered area within the grid on the map to open a new map showing details of the grid area.
Maps of MS4s designated under the Minnesota Rules Chapter 7090 are available on the Stormwater Program Rulemaking Web page.
The MS4 General Permit for MS4s near specially-protected waters require additional controls, conditions or an individual permit:
- MS4s that discharge near waters with qualities that warrant extra protection (special waters) must use additional best management practices and enhanced runoff controls (see permit Part IX).
- MS4s that discharge near an “impaired water” for which there is a total maximum daily load (TMDL) allocation for stormwater sources must meet special conditions (see permit Part IV.D).
The MPCA has several documents and an interactive map called Special Waters Search to help owners and operators of MS4s identify those waters near their MS4 that may require extra protections or an individual permit. The specific requirements are outlined in the MS4 General Permit.
- Special Waters List
- Stormwater and Impaired Waters
- Known Calcareous Fens List
- Final TMDLs and Implementation Plans
- Special and Impaired Waters Search: This is an electronic map tool using Geographic Information Systems (GIS) technology. Find the city boundary or site location of specific interest, draw the site boundaries and create a list of special waters.
MS4s are required to develop and implement a stormwater pollution prevention program (SWPPP) to reduce the discharge of pollutants from their storm sewer system to the maximum extent practicable. The SWPPP must cover six minimum control measures.
The MS4 must identify best management practices (BMPs) and measurable goals associated with each minimum control measure. An annual report on the implementation of the SWPPP must be submitted each year.
The MPCA will provide public notice and opportunity for public comment and hearing on each MS4s proposed SWPPP. Information on the public notice process is available at the MPCA Web page Public Notice Process for MS4 General Permit Applications.
Fact Sheets and Instructions
The new permit (MNR040000) becomes effective on May 21, 2013.
Identifies dates for MPCA and MS4 action items.
|Milestones under 2006 MS4 Permit|
Application Instructions and Application for General Stormwater Permit MNR040000 for Small Municipal Separate Storm Sewer Systems (MS4s) - issued March 2006 (wq-strm4-52)
Use SWPPP Pollution Prevention Guidance on the right:
Annual Reports are due June 30 of each year.
|MS4 Inspection and Recordkeeping|
Use these forms to to meet permit requirements for stormwater pond dredging for maintenance purposes.
|Managing Stormwater Sediment Best Management Practice Guidance for Municipalities|
- Managing Stormwater Sediment Best Management Practice Guidance for Municipalities
- Minnesota Rules - Storm Water Regulatory Program (Chapter 7090)
- Minnesota Rules - Waters of the State (Chapter 7050)
- MS4 Stormwater Program Overview
- Coal-tar Based Sealcoat: Environmental Concerns
- MS4 Inspection and Recordkeeping
- Municipal Stormwater Ponds
- Stormwater and Wetlands: Planning and Evaluation Guidelines
- Untreated Stormwater Runoff to Lakes, Streams, and Wetlands
- MS4 Education Toolkit
This education toolkit was funded by a grant through the MPCA to the Washington Conservation District.
- Minnesota Stormwater Manual
- International Stormwater Best Management Practices database
- EPA National Menu of Best Management Practices for Stormwater Phase II
- Protecting Water Quality in Urban Areas — MPCA Stormwater Best Management Practices Manual
- Plants for Stormwater Design
- Metropolitan Council Environmental Services — "Urban Small Sites Best Management Practices Manual"
- Center for Watershed Protection — "Stormwater Practices For Cold Climates"
- Water Resources Center — Assessment of Stormwater Best Management Practices Manual
Pollution prevention/good housekeeping
Illicit discharge, detection and elimination
The MPCA has various opportunities for receiving grants or loans for stormwater projects in Minnesota. Visit the following MPCA Web pages for information on water-related financial assistance:
- Funding for Wastewater and Stormwater
- Other Financial Assistance Opportunities — Grants and Loans
- Minnesota Stormwater Utility Survey
- Guidance for Municipal Stormwater Funding
Information for MS4s
- EPA Stormwater Phase II Final Rule - Fact Sheet Series
- National Pollutant Discharge Elimination System (NPDES) Stormwater Phase II Final Rule
- National Service Center for Environmental Publications (NSCEP)
- Stormwater Managers Resource Center
- Center for Global Environmental Education
- Stormwater Program for Construction Activity
- Stormwater Program for Industrial Activity
- University of Minnesota Impervious Cover and Updated Land Cover (2000) interactive maps
- Watershed Partners Public Education Tools
- NPDES Phase II Stormwater Program
- Environmental Stress from Urban Stormwater
Information for Citizens
For more information regarding the MS4 Stormwater Program, please contact the following staff. If outside the metro area, please call 1-800-657-3864.
Marni Karnowski, 651-757-2495
Duane Duncanson, 651-757-2323
TMDL/MS4 Permit technical assistance:
Wendy Gardner-Pritchard, 651-757-2090
The MPCA issued the original MS4 General Permit in June 2002. In July 2002, Minnesota Center for Environmental Advocacy (MCEA) filed an appeal of the permit. MCEA alleged several deficiencies, including: the inappropriate use of general versus individual permits, failure to address non-degradation issues, and the lack of adequate public participation and monitoring requirements.
In March 2003, over 200 owners and operators of small MS4s in urbanized areas applied for general permits, and began or expanded existing programs and practices to reduce stormwater runoff.
On May 6, 2003, the Minnesota Court of Appeals ruled that the use of general permits and best management practices was appropriate, and that the monitoring required in the permit was adequate. The court ruled that the use of general permits and best management practices was appropriate, and that the monitoring required in the permit was adequate. The court also called for the opportunity for public comment and public hearing on each permittee’s proposed stormwater pollution prevention program, required the MPCA to determine if additional control measures are necessary if the permittee has new or expanded discharges, and ruled that the language of Minnesota’s permit must follow federal language and require permittees to “reduce” (instead of “minimize”) pollutants. The complete opinion is available on the Minnesota Court of Appeals Web site.
Revisions were made to the permit to address the courts’ ruling. A draft permit was placed on a 30-day public notice comment period that began February 28, 2005. The comment period was extended until April 15, 2005. Two public information meetings on the draft permit were held during the comment period.
Numerous written comments were received during the comment period. After reviewing and considering all comments received, the MPCA made additional revisions to the draft permit to clarify permit requirements.
On February 28, 2006, the MPCA Citizens’ Board denied a request for a contested case hearing and approved the revised permit. The first reissuance of the permit became effective June 1, 2006.
The MS4 General Permit issued in 2006 addressed the new federal Phase II National Pollutant Discharge Elimination System (NPDES) stormwater regulations for small MS4s. These federal rules identified an iterative process for improved stormwater management where MS4 programs are strengthened with each five year permit cycle. This current permit reissuance effort shifts from the initial focus on permit program development to measuring program implementation. For the next MS4 General Permit reissuance (2017), the MPCA will need to comply with the new federal NPDES stormwater rules initially expected to be final in December 2012 (a revised date is pending) .
The draft MS4 General Permit was first placed on public notice May 31 through July 15, 2011. The MPCA held two public information meetings on the draft permit in June 2011; these meetings were webcast and the links are provided below. The MPCA received multiple requests to extend the public comment period on the draft permit, and subsequently extended the public notice comment period from August 8-29, 2011.
- Webcast - Informational meeting (published: 06/16/11)
- Webcast - Informational meeting (published: 06/14/11)
The MPCA received 35 comment letters and two contested case hearing requests on the draft permit. Staff reviewed and considered all comments received, and held four large group stakeholder meetings December 2011- March 2012, to discuss proposed concepts for revisions to the draft permit to address key permit issues identified in comments. Two of the four stakeholder meetings were webcast; the links are provided below. The draft permit was revised based in part on comments received and input obtained from the stakeholder meetings held on revisions to the draft permit, and is the subject of the public notice identified above.
- Webcast - Stakeholder meeting (published: 03/29/12)
- Webcast - Stakeholder meeting (published: 02/09/12)