Boone County, KY Environmental Rules: Flood Elevation Requirements (2026)

31. 31(A) requires the lowest floor, including the basement, mechanical equipment and ductwork, to sit no lower than one foot above the base flood elevation (BFE), the elevation shown on the FEMA Flood Insurance Rate Map for a flood with a 1% annual chance of occurrence. In an AO Zone without a mapped depth number, the structure must instead be elevated at least two feet above the highest adjacent grade. Where no FEMA technical data exists for an A Zone, the Floodplain Administrator determines the required elevation using hydrologic and hydraulic analysis, historical data, or the cross-section method described in 401 KAR Chapter 4, Regulation 060.

31(B) applies the same one-foot-above-BFE freeboard to commercial, industrial and nonresidential structures, or lets the owner floodproof the structure watertight below that elevation instead, with a registered engineer or architect certifying the floodproofing meets the standard. 04, defines FREEBOARD as a factor of safety, usually expressed in feet above the BFE, applied not just to the lowest floor but to building utilities and HVAC components too. Once built, a registered professional engineer or surveyor must certify the as-built lowest-floor elevation to the Floodplain Administrator, who verifies it with the community building inspection department. These freeboard rules apply only to the unincorporated county; Florence, Union and Walton run separate floodplain ordinances for land inside their limits.