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Stormwater Program for Municipal Separate Storm Sewer Systems (MS4)

Annual Report for 2014 now available

The MS4 Annual Report for 2014 is to be completed and submitted to the MPCA by June 30, 2015. For more information, visit the MS4 Annual Report page.

If you have TMDL reporting requirements, please see the Minnesota Stormwater Manual for guidance.

Who to contact

Having trouble finding who to contact with questions regarding your MS4?  Any member of the MS4 staff, listed under the Contacts tab below is available to answer your questions or direct you to the appropriate staff member. Additionally, you can find which staff member your MS4 is assigned to on the MS4 Permit Staff Assignments page. The list can be sorted alphabetically by clicking on the header: MS4 Name. 



According to the 1996 National Water Quality Inventory, stormwater runoff is a leading source of water pollution and can harm surface waters such as lakes, rivers, streams and wetlands. Common pollutants in stormwater runoff include pesticides, fertilizers, oils, metals, pathogens, salt, sediment, litter and other debris. These pollutants are transported via stormwater from a variety of sources including construction projects, industries and urbanized areas.

Aerial photo of urban storm-water runoff in Minnesota - Photo by Todd Smith, MPCAManagement of stormwater runoff from urbanized areas is very important for restoring or protecting surface waters. Urbanized areas are associated with activities that contribute pollutants to stormwater runoff, such as application of anti/deicing compounds, vehicle fueling, spills, landscaping and lawn maintenance, and application of pesticides and fertilizers. Additionally, urbanized areas are characterized by large amounts of impervious surfaces, such as streets, driveways, roof tops, parking lots and sidewalks. Stormwater runoff from impervious surfaces travels faster and in larger quantities, which results in damage to rivers, streams and wetlands; destruction of aquatic habitats; and elevated pollutant levels reaching surface waters. Impervious surfaces also inhibit infiltration and subsequent groundwater recharge. Local public entities that own or operate a municipal separate storm sewer system (MS4) in urbanized areas play a key role in preventing or reducing the negative impacts stormwater runoff may have on Minnesota’s valuable water resources.

What is an MS4

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, etc.) that is also:

  • owned or operated by a public entity (which can include cities, townships, counties, military bases, hospitals, prison complexes, highway departments, universities, etc.) 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.

The MS4 General Permit 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 subject to regulation under the National Pollutant Discharge Elimination System/State Disposal System (NPDES/SDS). Through the MS4 General Permit, the system 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:

What criteria make an MS4 subject to stormwater regulation?

An owner or operator of an MS4 in Minnesota is subject to stormwater regulation under the Clean Water Act due to one or more of the following reasons:

  1. An MS4 located in an urbanized area in whole or in part as determined by the latest Decennial Census, as regulated in accordance with Code of Federal Regulations.
  2. The entire jurisdiction of an MS4 owned or operated by a city or township that is located in an urbanized area in whole or in part as determined by the latest Decennial Census, as regulated in accordance with Code of Federal Regulations.
  3. An MS4 owned or operated by any publicly owned entity located within an urbanized area in whole or in part as determined by the latest Decennial Census, and which has a potential resident capacity or bed count occupancy of 1,000 or more.
  4. An MS4 owned or operated by a municipality with a population of 10,000 or more.
  5. An MS4 owned or operated by a municipality with a population of at least 5,000 and discharges or has potential to discharge stormwater to a water identified as an outstanding resource value water as identified in Minn R. 7050.0180, subparts 3 and 6.
  6. An MS4 owned or operated by a municipality with a population of at least 5,000 and discharges or has potential to discharge stormwater to a water identified as a trout lake or trout stream as identified in Minn. R. 6264.0050, subparts 2 and 4.
  7. An MS4 owned or operated by a municipality with a population of at least 5,000 and discharges or has potential to discharge stormwater to a water listed as impaired under section 303(d) of the Clean Water Act, 33 U.S.C. § 1313.

Minnesota state rules also establish criteria that can be applied to designate future MS4s under a formal designation process. MS4s that are designated through the petition process under Minn. R. 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.

Note: The cities of Minneapolis and St. Paul are Large MS4s, and received individual NPDES/SDS permits in 2000 that are reissued on a five year cycle.

Visit the Visit the Stormwater Program Rulemaking Web page for further details.

MS4 Mapping Tool

  • MS4 mapping tool:This is an interactive electronic 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. Note: This is best viewed with pop-up blockers disabled and screen resolution set to 1024x768 or higher.
  • PDF Document Guidance Document: Use of the MS4 Mapping Tool (wq-strm4-73)

Impaired waters and TMDLs

MS4 Permittees with assigned Waste Load Allocations (WLA) as part of a Total Maximum Daily Load (TMDL) project approved by US EPA prior to the effective date of the latest Permit reissuance must address additional information in their Stormwater Pollution Prevention Program (SWPPP). Permittees must develop a compliance schedule that outlines interim milestones it will achieve during the permit term, strategies for continued implementation beyond the permit term, and target dates to achieve the applicable WLAs.


MS4 permit requirements

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.

Public process for SWPPPs

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.

Permit and program forms



Fact Sheets and Instructions

PDF Document 2013 Reissuance of the General NPDES/SDS Permit MNR040000 for Municipal Separate Storm Sewer Systems (MS4s) (wq-strm4-59k)


PDF Document 2006 Issuance of the General NPDES/SDS Permit MNR040000 for Municipal Separate Storm Sewer Systems (MS4s) (wq-strm4-51)

The reissued permit (MNR040000) became effective on August 1, 2013.

PDF Document Revisions to MS4 SWPPP Requirements: (wq-strm4-49g)


Application Items


Fact Sheets and Instructions

MS Word Document Part 2 Application for MS4 General Stormwater Permit (SWPPP Document) (PDF Version) (wq-strm4-49l)

Application for Authorization

PDF Document MS4 SWPPP Application for Reauthorization (SWPPP Document) Example (wq-strm4-49b)
PDF Document Filling out the SWPPP Document - FAQs (wq-strm4-49h)

Individual MS4 SWPPP Document Submittal Dates

MS Excel Document MS4 Permit TMDL Attachment Spreadsheet (wq-strm4-49c)

Application supplement for MS4s with approved TMDL with a Waste Load Allocation (WLA) prior to the effective date of Permit.

PDF Document Guidance for MS4 TMDL Requirements (wq-strm4-49f)
PDF Document TMDL FAQs (wq-strm4-49k)
MS Excel Document Master List MS4 Permit TMDLs Spreadsheet (PDF Version) (wq-strm4-49d)
MS Word Document Alum or Ferric Chloride Phosphorus Treatment Systems Form (PDF Version) (wq-strm4-49e)

Application supplement for MS4s with alum or ferric chloride phosphorus treatments systems.

If applicable, must be submitted with MS4 SWPPP Application for Reauthorization (SWPPP Document).



Additional items


Fact sheets and instructions

MS4 Annual Reports

Annual Reports are due June 30 of each year.

Use SWPPP Pollution Prevention Guidance on the right. To update your current SWPPP to reflect changes in needs or when completing Annual Reports to aid in assessment of appropriateness of identified BMPs.

PDF Document MS4 Inspection and Recordkeeping (wq-strm4-05)

PDF Document Pollution Prevention and the MS4 Program (wq-strm4-26)

MS Excel Document Summary of Stormwater Pond Sediment Testing Results (wq-strm4-79)

Construction Stormwater General Permit

Use these forms to to meet permit requirements for stormwater pond dredging for maintenance purposes.

PDF Document Managing Stormwater Sediment Best Management Practice Guidance (wq-strm4-16)
MS Excel Document MS4 Pond, Wetland and Lake Inventory Form (PDF Version) (wq-strm4-30)

Inventory of all ponds, wetlands and lakes within permittee’s jurisdiction pertaining to 2009 Minnesota Session Law, Ch. 172. Sec. 28.

Must be submitted within 12 months of the date permit coverage is extended.


Guidance and BMPs

Minnesota Rules

Best Management Practices


Public Education and Outreach

Public Participation & Involvement

Illicit Discharge, Detection and Elimination

Construction Site Stormwater Runoff Control

Post Construction Stormwater Management

Pollution Prevention/Good Housekeeping For Municipal Operations

2013 Permit Reissuance: Filling out the SWPPP document

MPCA staff held workshops following the reissuance of the General NPDES/SDS Permit MNR040000 for Municipal Separate Storm Sewer Systems (MS4s), which became effect August 1, 2013. These events provided information to assist MS4s in filling out their SWPPP Documents, which are due for submittal on October 30 (Group 1), December 2 (Group 2) and December 30 (Group 3). See the video below for a recorded version of one of these workshops.

Video timeline guide:

  • Intro
  • 0:06:31 - Municipal Stormwater Regulations, Revisions to 2013 MS4 Permit, SWPPP Document Format
  • 0:26:18 - Application Process & Public Notice, BMP Table Examples
  • 0:48:20 - Questions on SWPPP Document
  • 0:58:26 - Guidance Documents on the MS4 webpage
  • 1:00:23 - TMDL Requirements in MS4 Permits
  • 1:55:56 - Questions on TMDL Requirements

Stormwater financial assistance

The MPCA has various opportunities for receiving grants or loans for stormwater projects in Minnesota. Visit the following MPCA webpages for information on water-related financial assistance:


For more information regarding the MS4 Stormwater Program, please contact the following staff. If outside the metro area, please call 1-800-657-3864.


Duane Duncanson, 651-757-2323

Permit writer:

Duane Duncanson, 651-757-2323

Technical assistance and compliance enforcement:

Scott Fox, 651-757-2368
Claudia Hochstein, 651-757-2881
Cole Landgraf, 651-757-2880
Dan Miller, 651-757-2246
Rachel Stangl, 651-757-2879

Individual MS4 Staff Assignments

TMDL/MS4 Permit technical assistance:

Josh Stock
, 651-757-2235

Application processing

Wendy Gardner-Pritchard, 651-757-2090

Last modified on November 04, 2015 14:05