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MS4 Individual Permits

Municipal Separate Storm Sewer Systems

MS4 stands for municipal separate storm sewer system. Some cities and universities in Iowa must abide by an additional stormwater permit to mitigate pollution that enters the sewer system and to keep local waterways clean. MS4s are determined by the Iowa Department of Natural Resources and primarily dependent on population or proximity to a metropolitan area.

Permitted MS4s are required to have a construction site runoff erosion control ordinance and a post construction stormwater ordinance in place. Their program must also meet 6 minimum requirements.

  1. Public outreach on stormwater impacts
  2. Public involvement and participation
  3. Illicit discharge and elimination program
  4. Construction site regulations
  5. Post-construction on stormwater management
  6. Good housekeeping policies

The majority of MS4s in Iowa are members of ISWEP. ISWEP assists cities with the public education and outreach portion of their permit. Through ISWEP training and certification programs, we also help city staff and contractors learn about best management practices applicable to their projects.

The following cities and universities are required to obtain a permit for their Municipal Separate Storm Sewer System (MS4). If you plan to do work in one of the following cities or universities, please consult with their stormwater coordinator to ensure you are meeting MS4 regulations. Click Here to see a map.