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

Jefferson County's floodplain zoning ordinance (Ch. 6, Art. III, adopted by Ord. No. 2025-07 on July 14, 2025) covers the floodway, floodfringe, general floodplain, and flood storage districts mapped on the FEMA Flood Insurance Rate Maps for the county. Under Sec. 6-184(f), no structure or use in a regulated floodplain area may be located, erected, constructed, reconstructed, repaired, extended, converted, enlarged, or altered without full compliance with the article, and failing to obtain a floodplain development permit is itself a violation. Sec. 6-304(b) requires a land use permit before any new development, repair, modification, addition, or change in use, including sewer and water facilities, and the application must include a site plan showing lot elevations, structure locations, on-site sewage or well locations, and the elevation of the lowest floor of any proposed building or fill.

The zoning administrator reviews applications to confirm the site will be reasonably safe from flooding and that no proposed development will obstruct floodwater flow or raise the regional flood height (Sec. 6-185, Sec. 6-186); permits are denied outright if either standard is not met. Permits issued under the article expire 180 days after issuance unless extended for good cause, and work not started within that window must comply with any FIRM or FIS revision that has since taken effect (Sec. 6-304(b)(4)). A certificate of compliance from the zoning administrator, backed by a registered engineer's, architect's, or surveyor's certification of fill and floor elevations, is required before the building or land may be occupied (Sec.

6-304(c)). Existing zoning officials appointed under the county's Wis. 692 zoning ordinance also administer this floodplain article (Sec. 6-303), and the county board of adjustment created under Wis. 694 hears boundary disputes, appeals, and variance requests (Sec. 6-306).