Substantial improvement outside the Town — Charleston County Code Chapter 9

For unincorporated Charleston County and the municipalities the County inspects, the governing law is Charleston County Code Chapter 9, 'Flood Damage Prevention and Protection.' Chapter 9 was replaced by Ordinance No. 2124 adopted 10/6/2020, and Ordinance No. 2306 adopted 8/13/2024 is the current version listed on the County's Codes & Ordinances page. County rule as published: 'if the cost of reconstructing, rehabilitating, adding to, or otherwise improving a structure equals or exceeds 50 percent of the building's assessed or appraised value, then the building must meet the same construction requirements as a new building,' with a five-year permit-value look-back, enforced through the construction permitting process. County construction standards in A/AE/AH/AO/A99 zones: finished floor of new and substantially improved residential structures at least two feet above BFE; only non-residential structures may be floodproofed to two feet above BFE in lieu of elevating, with pre-construction and as-built Floodproofing Certificates sealed by a SC registered architect or PE; with the exception of one GFCI outlet and switch, no wiring, plumbing, mechanical fixtures, equipment, appliances or ductwork below two feet above BFE; flood openings at minimum two openings on different walls within 12 inches of grade at one square inch per square foot of enclosed area; only FEMA Technical Bulletin 2 Class 4 or 5 flood-resistant materials below BFE; uses below BFE limited to building access, vehicle parking and limited storage of yard equipment. Contact: (843) 202-6930, FloodServices@CharlestonCounty.org. CAUTION: Ordinance 2306 is posted as a scanned image PDF with no extractable text, so the section-level text quoted here is from Ordinance 2124 and the County's current published FAQ, not from 2306 itself. Checked 2026-09-04.