Overview

All new or substantially improved buildings in the Special Flood Hazard Area (SFHA) are required to comply with all current flood design requirements and obtain Elevation Certificates and other construction certifications. View flood design requirements here: Building Codes and Construction in Flood Zones

Ensure all local, state and federal permits are obtained before construction work commences. To obtain a City of Charleston building permit, please visit our Permit Center. 

A building permit is required for all development in the Special Flood Hazard Area, including storm damage repairs to ductwork, flooring and roofs. 

Converting existing storage and garage enclosures into habitable space may have implications on insurance or local compliance.

Illegal floodplain development, illicit discharges and unpermitted work should be reported to the Citizen Services Center.

Flood hazard areas may contain wetland or beachfront areas which serve natural and beneficial functions. Activities that disturb beachfront and wetlands should not be undertaken without first obtaining permits from the South Carolina Department of Health and Environmental Control Office of Ocean and Coastal Resource Management. Any disturbance of freshwater wetlands requires a permit from the U.S. Army Corps of Engineers and certification from S.C. DHEC's Office of Ocean and Coastal Resource Management.

Substantial Improvement/Damage 'SI/SD' or '50% Rule':

The above Table demonstrates the "Freeboard" level or the factor of safety expressed in feet above the Base Flood Elevation for purposes of Floodplain Management.

• The National Flood Insurance Program requires that 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.
• Structures which are damaged, due to any cause, by 50% or more of the building's value are required to be brought into compliance with current floodplain requirements.
• Structures that undergo a cumulative improvement cost of 50% or more of the building's value over the past year (such as a home renovation) must comply with current City floodplain management requirements.
• This regulation is enforced through the construction permitting process. The Substantial Improvement Package must be submitted during permitting.

Higher Standards and Updates

• Ordinance to Prohibit Slab-on-Grade Foundations: Prohibition of building diagrams 1A, 1B, 2A, and 3 in the SFHA or 100-year Floodplain became effective for projects applied on or after January 1, 2024
  • View Answers to Frequently Asked Questions Here
• Coastal A Zone: As of January 1, 2023 the City of Charleston enforces Coastal A Zone building flood design & construction requirements for all new construction and substantial improvements based on 2021 South Carolina Building Code (SCBC) §1612 and 2021 South Carolina Residential Code §R322, which became effective statewide January 1, 2023.
  • CoC---Coastal-A-Zone-Guidance
• Freeboard Increase: Effective July 1st, 2020, all residential & non-residential new construction, and non-residential substantial improvements, in the Special Flood Hazard Area (SFHA) must be designed 2 ft. above Base Flood Elevation (BFE). Residential substantial improvement will remain at 1 ft. above BFE.
  • See our Flood Design Compliance Matrix for more information