Appleton, WI Environmental Rules: Flood Elevation Requirements (2026)

Appleton Municipal Code § 23-253(a) governs elevation requirements for any residential structure, including a manufactured home, newly built or moved into the city's Floodfringe District (FF). Under § 23-253(a)(1), the lowest floor must sit at or above the flood protection elevation when the structure is built on fill, and that fill must extend one foot or more above the regional flood elevation for at least 15 feet beyond the structure's limits. Section 23-315 defines flood protection elevation as two feet of freeboard above the water surface profile elevation set for the regional flood, so the practical floor requirement is regional flood elevation plus two feet.

Section 23-253(a)(2) allows a basement or crawlway floor to sit at the regional flood elevation only if it is dry floodproofed to the flood protection elevation, but no floor of any kind may go below the regional flood elevation itself. Accessory structures under § 23-253(b) must be built on fill with the lowest floor at or above the regional flood elevation. Commercial structures follow the same residential standard under § 23-253(c), while manufacturing and industrial buildings under § 23-253(d) must either elevate the lowest floor to the flood protection elevation or meet the dry-floodproofing standards of § 23-295.

Contiguous dryland access from the structure to land outside the floodplain is required under § 23-253(a)(3) unless the city has written assurance from police, fire and emergency services that wheeled-vehicle rescue is available, or a DNR-approved evacuation plan is in place. A land use permit from the zoning administrator, per § 23-291, is required before any of this construction begins, and elevation certification documentation is part of that permit record.