Legislation passed in 2019, and subsequently amended in 2021, changed the regulated area for certain MS4s. Click here see referenced legislation. This page explains the legislation and how it affects the regulation of those MS4s.

2019 Legislation

The initial legislation took effect August 1, 2019.

Laws 2019, First Special Session chapter 4, article 3, section 109, as amended by Laws 2020, chapter 83, article 1, section 100, is amended to read:


Until the Pollution Control Agency amends rules for storm water, Minnesota Rules, part 7090.1010, subpart 1, item B, subitem (1), applies only to the portions of a city, a town, and unorganized areas of counties or township that are designated as urbanized under Code of Federal Regulations, title 40, section 122.26(2)(9)(i)(A), and other platted areas within that jurisdiction those jurisdictions.

What does this legislation mean?

Prior to this legislation, cities and townships exclusively regulated under Minn. R. 7090.1010, subp. 1(B)(1)1, were required to manage stormwater in compliance with the general permit for small MS4s in the “entire” jurisdiction. The 2019 legislation reduces the land area in which stormwater must be managed within the permittees’ jurisdiction to only the Urbanized Area (UA), as defined by the most recent decennial census, and other “platted areas” as defined by Minnesota Statute 462.352, subd. 1322. There are 38 MS4s affected by this legislation. See list below.

1 Any MS4s partially in urbanized area with populations up to 4,999 or between 5,000-9,999 and not discharging to a special water.

2 Minn. Stat. 462.352, subd. 13: "Plat" means the drawing or map of a subdivision prepared for filing of record pursuant to chapter 505 and containing all elements and requirements set forth in applicable local regulations adopted pursuant to section 462.358 and chapter 505.

Affected MS4s

Cities Townships
Carver City MS4 Brockway Township MS4
Dayton City MS4 Cascade Township MS4
Dellwood City MS4 Duluth Township MS4
Dilworth City MS4 Empire Township MS4
Eagle Lake City MS4 Jackson Township MS4
Grant City MS4 Laketown Township MS4
Hanover City MS4 Le Sauk Township MS4
La Crescent City MS4 Louisville Township MS4
Long Lake City MS4 Mankato Township MS4
Medina City MS4 Marion Township MS4
Newport City MS4 Midway Township MS4
North Oaks City MS4 Minden Township MS4
Nowthen City MS4 Rochester Township MS4
Proctor City MS4 Sauk Rapids Township MS4
Rice Lake City MS4 South Bend Township MS4
Saint Augusta City MS4 Spring Lake Township MS4
Skyline City MS4 St. Joseph Township MS4
St. Bonifacius City MS4 Watab Township MS4
Wayzata City MS4 West Lakeland Township MS4

Other impacts due to this legislation

Changes in regulated area for these 38 MS4s due to the 2019 legislation generates uncertainty about the degree of applicability for some of their previously assigned US Environmental Protection Agency (EPA) approved wasteload allocations (WLAs). For example, if a Total Maximum Daily Load (TMDL) study area includes a portion of an affected city or township that has no urbanized or platted areas, that EPA approved WLA may not be applicable to the permittee this permit term.

Next Steps

The MPCA is working on identifying platted areas by using the Parcels Compiled from Open Data Counties dataset. For counties that are not included in that dataset, the parcel data found on county websites is being used. The platted areas identified in the parcel datasets will eventually be added to the Stormwater Mapping Tool. In this way, the affected cities and townships will be able to more easily identify their regulated area per the 2019 Legislation. The target date for getting the platted areas added to the map will be Fall 2022.