Building Construction in Flood Zones

Flood Zones in the City of Charleston

It is critical to remember that the City of Charleston, being located in the Atlantic Coastal region, is subject to flooding from the Atlantic Ocean as well as inland flooding from rivers and associated tributaries. Charleston is also subject to storm surge, flooding from heavy rains and high tides.

Being prepared is your best defense against such events.

Property Flood Zones

To find out what flood zone your property is located within, FEMA has a searchable map provided for free on their website. 

Types of Flood Zones

Moderate to Low-Risk Areas

  • Shaded Zone X: Areas of 500-year flood; areas of 100-year flood with average depths of less than 1 foot or with drainage areas less than 1 square mile; and areas protected by levees from 100-year flood. 
  • Zone X: Areas determined to be outside 500-year flood plain.

High-Risk Areas

  • Zone A: No base flood elevations determined. 
  • Zone AE: Base flood elevations determined.
  •  Zone AH: Flood depths of 1 to 3 feet ( usually areas of ponding); base flood elevations determined. 
  • Zone AO: Flood depths of 1 to 3 feet (usually sheet flow on sloping terrain); average depths determined. For areas of alluvial fan flooding, velocities also determined. 
  • Zone A99: To be protected from 100-year flood by Federal flood protection system under construction; no base flood elevations determined. 

High Risk - Coastal Areas

  • Zone V: Coastal flood with velocity hazard (wave action); no base flood elevations determined.
  • Zone VE: Coastal flood with velocity hazard (wave action); base flood elevations determined.

Undetermined Risk Areas

  • Zone D: Areas in which flood hazards are undetermined but possible.

Steps to Take if Your New Building Construction or Renovation Is Located in a Flood Zone

You may need to submit the following documents when applying for building and trade permits:

Please be advised all work (including painting, interior finishes, etc.) in a Special Flood Hazard Area requires a permit.

Additional Information

Floodplains are a natural component of the City of Charleston environment. Understanding and protecting the natural functions of floodplains helps reduce flood damage and protect resources. Floodplains are scenic, valued wildlife habitat, and suitable for farming. Poorly planned development in floodplains can lead to stream-bank erosion, loss of valuable property, increased risk of flooding to downstream properties and degradation of water quality.

Related Information & Documents