Environmental Rules in Green Bay, WI (2026)

Flood Zones

The City of Green Bay participates in the National Flood Insurance Program and regulates floodplain development through Article XIII (Floodplain Overlay District) of its zoning code, adopted under Wis. Stat. Sec. 87.30 and the minimum standards of Wis. Admin. Code Chapter NR 116. Primary flood sources are the Bay of Green Bay, the Fox River, the East River, and Mahon Creek. FEMA issued updated Flood Insurance Rate Maps for Brown County that became effective May 9, 2023, and these are the maps now used to delineate Special Flood Hazard Areas. New residential structures are prohibited in the regulatory floodway, and floodplain development requires zoning approval before any building permit is issued.