Nash County, NC Environmental Rules: Flood Elevation Requirements (2026)

4 of the Unified Development Ordinance, within the Flood Hazard Overlay District rules, sets the elevation standard once base flood elevation data has been provided for an area of special flood hazard. Under (D)(1) Residential Construction, new construction or substantial improvement of a residential structure must have the lowest floor, including a basement, elevated one foot above the base flood elevation; if solid foundation perimeter walls are used instead of open piers, the walls must include openings sized to let floodwaters move through unimpeded. Under (D)(2) Nonresidential Construction, commercial, industrial or other nonresidential structures face the identical one-foot-above-BFE elevation standard for their lowest floor, though those structures in A-zones may instead be flood-proofed, with a registered engineer or architect certifying that the flood-proofed design is watertight and can resist hydrostatic and hydrodynamic loads.

Manufactured homes get the same one-foot freeboard requirement under (D)(3), whether placed in a new park, an expansion, or an existing park after a flood-related substantial improvement, and must be securely anchored to resist flotation, collapse and lateral movement. 4(E)(2) instead requires the lowest floor to sit at least two feet above the highest adjacent grade, a stricter fallback for areas without mapped BFE numbers.