Skip to main content

Individual and General MS4 Permits

In the state of Wisconsin, there are a total of 245 municipal separate storm sewer system (MS4) permittees (last updated June 2024). Of the 245 MS4 Permittees, each region has the following:

  • Northeast Region: 49 MS4s; All Permittees are covered under the General MS4 Permit.
    • Counties Covered: Brown, Calumet, Door, Fon Du Lac, Kewaunee, Manitowoc, Marinette, Menominee, Oconto, Outagamie, Shawano, Waupaca, and Winnebago.
  • Southeast Region: 103 MS4s; 35 Permittees covered under an Individual Group Permit, 14 Permittees under Individual MS4 Permits, 54 Permittees covered under the General MS4 Permit.  
    • Counties Covered: Sheboygan, Washington, Ozaukee, Milwaukee, Waukesha, Racine, Kenosha, and Walworth.
  • South Central Region: 47 MS4s; 21 Permittees covered under an Individual Group Permit, 26 Permittees covered under the General MS4 Permit.
    • Counties Covered: Columbia, Dane, Dodge, Grant, Green, Iowa, Jefferson, Lafayette, Richland, Rock, and Sauk.
  • Northern West Central Region: 46 MS4s; All Permittees covered under the General MS4 Permit.
    • Counties Covered: Adams, Buffalo, Crawford, Jackson, Juneau, La Crosse, Monroe, Trempealeau, Vernon, Dunn, Eau Claire, Pepin, Pierce, Polk, St. Croix, Florence, Forest, Langlade, Lincoln, Marathon, Oneida, Portage, Wood, Ashland, Bayfield, Burnett, Douglas, Iron, Vilas, and Washburn.  

To learn more about the criteria for whether a community requires a MS4 permit, please see the municipal stormwater permit overview.

General MS4 permit

View and download the current General MS4 permit.

Individual MS4 Permits

An individual MS4 Permit may be given to a single community but, may also be given to a group of individual communities. Though a group MS4 permit contains multiple communities, it is still considered an Individual MS4 Permit. Some communities find group permits beneficial for reasons such as enhanced collaboration. However, each individual community is still required to comply with its MS4 Permit. 

Note: Last updated December 2024. Some MS4 permits may be expired and have yet to be reissued. Though it has expired, the permit has been administratively extended and Permittees must continue to implement current permit conditions until the next permit is issued.

Southeast Region

South Central Region:  

Non-Traditional MS4s  

Even though MS4 permits are typically given to communities (i.e., cities, villages, towns, and counties), MS4 permits are also given to non-traditional permittees, such as Universities, which have public separate storm sewer systems.