Florence County, SC Hurricane Preparedness: Flood Elevation (2026)

Most new construction and substantial improvements in unincorporated Florence County's Special Flood Hazard Areas only need to clear the base flood elevation by one foot under § 30-62(b). But § 30-62(a)(4), captioned 'Critical development,' sets a materially higher bar within the same list of general standards that applies in all areas of special flood hazard: such structures must be elevated to the 500-year flood elevation, or to the highest known historical flood elevation where records exist, whichever produces the greater height. If neither figure has been established for the site, the applicant cannot default to the ordinary base flood elevation; § 30-62(a)(4) requires a hydrologic and hydraulic engineering analysis, performed to generate 500-year flood elevation data specifically, before the local administrator can process the development permit.

That analysis sits alongside the other general standards in § 30-62(a): anchoring against flotation and lateral movement, flood-resistant construction materials, and utility equipment located or floodproofed to withstand the base flood plus one foot. The ordinance text does not further define which uses count as 'critical development' beyond this heading, so the elevated-to-500-year-standard duty applies within the general standards section covering new construction and substantial improvements described in § 30-62(a), and it is enforced through the same local administrator permit review, certification, and stop-work process set out in § 30-61.