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

Greenville County's flood damage prevention article defines freeboard, in Section 8-28, as the safety margin added above the calculated flood level to cover unknowns like wave action and the hydrological effect of urbanizing a watershed. That margin is set as a hard number in Section 8-33(a): new construction and substantial improvement of any residential structure, including manufactured homes, must have its lowest floor and all associated electrical, ventilation, plumbing, heating and air conditioning equipment, including ductwork, elevated no lower than 4 feet above the base flood elevation, and no basements are allowed.

The same 4-foot freeboard standard applies to new or substantially improved non-residential structures under Section 8-33(b), though those buildings may be floodproofed instead of elevated if every area below the required elevation is watertight and built to resist hydrostatic and hydrodynamic loads. Where solid foundation perimeter walls are used to elevate a structure, the walls must include openings sized to let floodwater move through unimpeded, per the flood-vent standards in Section 8-34(f). A South Carolina registered professional engineer or architect must certify that a structure meets the Section 8-33 elevation or floodproofing standard, and that certification goes to the local flood administrator.

Floodproofed structures also need an approved maintenance plan with an annual exercise, reviewed by the administrator. 2% annual-chance flood hazard area regardless of elevation or floodproofing.