Anderson County, SC Environmental Rules: Flood Elevation Requirements (2026)

County Code § 24-663 sets the specific elevation standards that apply once base flood elevation data exists for a special flood hazard area. New construction and substantial improvement of any residential structure, including manufactured homes, must have the lowest floor elevated no lower than two feet above the base flood elevation, with no basements permitted; where solid foundation perimeter walls elevate the structure, flood openings must automatically equalize hydrostatic forces. Nonresidential structures face the same two-foot elevation floor, or may be dry-floodproofed instead in A zones if a registered professional engineer or architect certifies the space below that level is watertight and can resist hydrostatic and hydrodynamic loads, subject to an approved annual maintenance-plan exercise.

Manufactured homes placed on new or existing park sites must likewise have their lowest floor elevated two feet above the base flood elevation and be anchored to resist flotation, collapse and lateral movement, with an engineering certification required once the chassis elevation exceeds 36 inches. Under § 24-662(5), critical development such as jails, hospitals, schools, fire stations, nursing homes, wastewater treatment plants and water plants must be elevated to the 500-year flood elevation or the highest known historical flood elevation, whichever is greater, or supported by a hydrologic and hydraulic engineering analysis generating that data.

The code defines freeboard, in § 24-610, as a safety factor above a flood level meant to compensate for unknown contributors to flood heights, such as wave action and watershed urbanization, which is why the two-foot figure sits above the base flood elevation rather than at it.