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

Greenwood County Code Sec. 6-6-32, "Specific standards," part of Title 6, Chapter 6's Floodplain Management ordinance, applies wherever base flood elevation data has been provided for an area of special flood hazard. Subsection (1) requires new construction or a substantial improvement of any residential structure to have its lowest floor, including any basement, elevated no lower than one foot above the base flood elevation, and if solid perimeter foundation walls are used to achieve that elevation, they must include openings that let floodwaters move through unimpeded.

Subsection (2) applies the same one-foot freeboard standard to commercial, industrial, or other nonresidential construction, but lets those structures be floodproofed instead of elevated, provided every area below the required elevation is watertight, with walls able to resist hydrostatic and hydrodynamic loads, certified by a registered professional engineer or architect. Subsection (3) requires elevated buildings with an enclosed area below the base flood elevation to be designed so floodwaters can automatically enter and exit to equalize pressure, generally through openings totaling at least one square inch of net area per square foot of enclosed space.

Subsection (4) bars placing mobile homes in a floodway or coastal high hazard area except in an existing mobile home park or subdivision, and requires anchoring to resist flotation and lateral movement. Subsection (5) prohibits encroachments, including fill and new construction, within a designated floodway unless an engineer certifies no increase in flood levels will result. A newer, overlapping overlay-zone ordinance adopted in 2011, Sec. 6-6-56(c), imposes the identical one-foot freeboard requirement and bars basements outright, administered by the director of the Greenwood County Planning Department as zoning administrator for the flood management overlay zone.