Charleston County, SC Environmental Rules: Flood Zones (2026)

Charleston County participates in the National Flood Insurance Program (NFIP) and enforces floodplain rules through Chapter 9 of its Code of Ordinances (Flood Damage Prevention and Protection). The chapter has been amended several times, most recently by Ordinance No. 2306 (adopted August 13, 2024) which superseded prior Ordinance No. 2245, which itself replaced Ordinance No. 2124. The Charleston County Flood Insurance Study and Flood Insurance Rate Maps (FIRMs) effective January 29, 2021 are formally adopted as part of Chapter 9. The unincorporated county joined the CRS in 1994 at Class 9 and has progressively earned its way to Class 2, one of only a handful of communities nationwide at this elite tier; this provides a 40% flood insurance premium discount for NFIP policyholders in unincorporated Charleston County (increased from 35%). Per the Building Inspection Services Department, the finished floor of all new and substantially improved residential structures in A, AE, AH, AO, and A99 zones must be elevated to a minimum of 2 feet (24 inches) above the Base Flood Elevation (BFE). To support CRS scoring, structures in Coastal A zones (LiMWA areas where 1.5-foot waves are expected) must follow the same V/VE zone standards, including pile or column foundations and breakaway walls. A finished construction Elevation Certificate completed by a South Carolina registered land surveyor must be submitted to Building Inspection Services prior to final inspection (foundation inspections are excepted). Under the NFIP substantial improvement / substantial damage rule (50% of market value), repairs or improvements that meet or exceed half the structure's assessed value require the building to be brought into full compliance with current floodplain standards; permit values issued in the prior five years are aggregated toward this threshold. Property owners can request Letters of Map Amendment (LOMA) or Letters of Map Revision (LOMR) through FEMA's Map Service Center. The Building Inspection Services Department, located at the Lonnie Hamilton III Public Services Building in North Charleston, maintains Elevation Certificates on file for structures built since the late 1970s.