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

The City of Milton's floodplain zoning ordinance, readopted in its entirety on September 15, 2015 under the authority of Wis. 23 and the state floodplain mandate in Wis. 30, defines 'flood protection elevation' in Sec. 79-6 as two feet of freeboard above the water surface profile elevation for the regional flood, a margin meant to absorb ice jams, debris, wave action and the effects of watershed urbanization that the calculated flood level does not capture. That definition drives the construction standards in Article IV. Under Sec.

79-63(1)(a), any structure newly built or moved into the floodfringe district, including a manufactured home, must have its lowest floor at or above the flood protection elevation on fill, with the fill extending at least 15 feet beyond the structure and rising at least one foot above the regional flood elevation; a basement or crawlway floor may instead sit at the regional flood elevation only if it is dry floodproofed up to the flood protection elevation, and no basement floor is ever allowed below the regional flood elevation.

Accessory structures need their lowest floor at or above the regional flood elevation under Sec. 79-63(2)(a). In the general floodplain district's AO and AH zones, Sec. 79-81(c)(1) requires the lowest floor to meet whichever standard is highest: the flood protection elevation, two feet above the highest adjacent grade, or the flood depth shown on the FIRM. The floodway district, mapped as AE zones, layers on stricter limits: Sec. 79-102 bars any enclosed foundation area below the flood protection elevation unless it is built of flood-resistant material with flood-vent openings and limited to parking, access or storage.

Any map amendment changing these elevations needs DNR and FEMA review under the letter of map change process described in Sec. 79-5(b) before a land use permit can issue.