Milwaukee County, WI Environmental Rules: Flood Zones (2026)

Wis. Stat. §87.30(1) requires each municipality with land in a 100-year floodplain to adopt a reasonable and effective floodplain zoning ordinance, and Wis. Admin. Code ch. NR 116 (Wisconsin's Floodplain Management Program) sets the minimum standards. Per NR 116.03(28), Wisconsin defines the 'flood protection elevation' as 2 feet above the regional flood elevation - giving Wisconsin a state-mandated 2-foot freeboard that exceeds the FEMA NFIP baseline. NR 116.13 prohibits new structures in the floodway and limits flood-fringe construction: residential structures must have the lowest floor (including basement) at or above the flood protection elevation, and accessory structures may not be inundated more than 2 feet or subjected to flood velocities greater than 2 feet per second during the regional flood. NR 116.21(4)(b) prohibits variances that allow a lower degree of flood protection than the flood protection elevation. Basements below the regional flood elevation are not permitted (except for certain pre-1986 FEMA exceptions). Milwaukee County is exposed to riverine flooding along the Milwaukee, Menomonee, Kinnickinnic, and Root rivers, plus Lake Michigan shoreline coastal hazards. The Milwaukee Metropolitan Sewerage District (MMSD) and Southeastern Wisconsin Regional Planning Commission (SEWRPC) maintain regional models, and SEWRPC is finalizing updated 100-year floodplain maps for the Kinnickinnic Watershed in the City of Milwaukee that show larger areas at risk than the existing FEMA maps. The City of Milwaukee administers floodplain zoning through Code of Ordinances Ch. 295, Subchapter 11 (Floodplain Overlay Zones); other municipalities adopt similar overlay districts. Effective FEMA Flood Insurance Rate Maps (FIRMs) for Milwaukee County are available through the FEMA Map Service Center.