Stormwater Utility • Annual Reports
Municipal Storm Water Permit (MS4)
More than two hundred municipalities in Wisconsin that include cities, villages, towns and counties within urbanized areas are required to have Municipal Separate Storm Sewer System (MS4) permits under NR 216, Wis. admin. code.
An MS4 permit is required for a municipality that meets one of the following criteria
It is located within a federally-designated urbanized area.
Its population equals 10,000 or more based on the latest decennial census;
When the Department of Natural Resources designates the municipality for permit coverage in accordance with s. NR 216.025. The MS4 permits are effective for a period of up to five years, at which point the permits are updated and re-issued.