Green Bay, WI Environmental Rules: Flood Elevation Requirements (2026)

Section 8-166(a) sets the baseline rule: the first habitable floor of any building or structure cannot go below the current City elevation. Subsection (b) adds that any use requiring floodproofing must be designed to the current flood protection elevation, and the Director can require a plan certified by a registered professional engineer or architect showing the floodproofing measures meet that elevation. The ordinance lists ten specific measures that qualify, including watertight doors, bulkheads and shutters; reinforced walls that resist water pressure; paint, membrane or mortar to cut seepage; water supply and waste systems built to keep out floodwater; subsurface drainage pumps for foundations and basements; construction that resists rupture from water pressure or floating debris; backwater valves on sewer lines or elimination of gravity-flow basement drains; anchorage against flotation and lateral movement; added mass to resist flotation; and pumps to lower interior water levels.

Subsection (c) allows accessory uses, parking lots, yards and similar open-land uses to sit at the base flood elevation itself, a lighter standard than habitable structures. Subsection (d) requires any fill placed around a building to reach at least one foot above base flood elevation and extend at that height for a minimum of 15 feet in every direction from the structure, with the fill stabilized against erosion using methods the U.S. Soil Conservation Service recommends. The section was rewritten in the City's 2024 building code overhaul, Ordinance No. 13-24, adopted July 30, 2024, which repealed and replaced the former Chapter 8 in full.