Dane County, WI Environmental Rules: Flood Elevation Requirements (2026)

Chapter 17, the county's Floodplain Zoning ordinance, defines 'Flood Protection Elevation' in s. 06(33) as an elevation of two feet of freeboard above the Regional Flood Elevation, a cushion meant to compensate for factors like ice jams, debris accumulation, wave action, and watershed urbanization that can push actual flood heights above the calculated regional flood level. That two-foot standard becomes an operative construction requirement in s. 09(3)(a)1, which governs residential development in the Floodfringe District: any structure, including a manufactured home, that is newly constructed or moved into the floodfringe, and any substantial improvement of an existing residential structure, must have its lowest floor elevated to or above the flood protection elevation, or alternatively meet the dry-floodproofing standards spelled out in s.

12(5). Accessory structures face a related but distinct standard under s. 09(3)(b), new construction and substantial improvements must be built on fill with the lowest floor at or above the plain regional flood elevation, without the extra two-foot freeboard. The Dane County Zoning Division administers floodplain permits and serves as floodplain administrator for the unincorporated, rural portions of the county; incorporated cities and villages within Dane County, including Madison, administer their own floodplain ordinances for land inside their limits.