York County, VA Environmental Rules: Flood Elevation Requirements (2026)

Sec. 24.1-373(e)(9) sets the construction standards for Zone AE and AH, the areas where FEMA has mapped detailed base flood elevations. New construction and substantial improvements must follow the Virginia Uniform Statewide Building Code's floodplain provisions, and the Floodplain Administrator must confirm compliance before issuing building permits or certificates of occupancy. The lowest floor of any residential structure, including a basement, must carry a freeboard of at least three feet above the base flood elevation; non-residential buildings may be floodproofed instead, provided everything below the base flood elevation plus one foot is watertight and can resist hydrostatic and hydrodynamic loads, certified by a registered engineer or architect.

Electrical equipment, heating and cooling systems, and electrical distribution panels must also sit at least three feet above the base flood elevation. Coastal AE zones within the Limits of Moderate Wave Action, subject to 1.5-3 foot wave heights, must add one more foot for four feet of total freeboard. In Zone AO, where flood depths rather than elevations are mapped, the lowest floor must be elevated to the mapped depth number plus freeboard, or at least two feet above the highest adjacent grade if no depth number is shown.

Any enclosed area below the lowest floor in Zones A, AE, AH, or AO can only be used for parking, building access, or storage, must use flood-resistant materials, and needs flood vents totaling at least one square inch of net opening per square foot of enclosed area, with openings on at least two different sides.