New Berlin, WI Environmental Rules: Flood Elevation Requirements (2026)

New Berlin folds its base-flood-elevation and freeboard requirements into the development standards for each floodplain district in § 275-65. In the Floodfringe District, § 275-65 D(3)(a) requires any newly constructed or relocated residential structure, including a manufactured home, to have its lowest floor elevated to or above the flood protection elevation, and that elevation must be achieved on fill: the fill placed around the structure has to reach at least one foot above the regional flood elevation and extend at least 15 feet beyond the structure's outer limits.

An existing structure already standing in the floodfringe is instead held to the nonconforming-use standards in § 275-65 F rather than this new-construction rule. The code applies a parallel but distinct standard to Zone AO parcels inside the General Floodplain District: § 275-65 E(1)(d)[1][a] requires the lowest floor, including any basement, to be elevated to or above the depth shown on the Flood Insurance Rate Map above the highest adjacent natural grade, plus one additional foot of freeboard, or, where the FIRM does not specify a depth, to or above three feet above the highest adjacent grade.

Zone AH structures in the same district must instead reach the flood protection elevation outright. Public utilities and equipment serving these structures must also be elevated to or above the flood protection elevation, and sanitary sewer, well and septic components are separately required to be designed to minimize floodwater infiltration up to that same elevation. These are development standards enforced at the permit stage: the Department of Community Development will not issue a floodplain development permit for a design that leaves the lowest floor below the required elevation.