For all building permit applications applied for before July 1, 2020, the additional minimum flood protection requirement above the Base Flood Elevation (BFE) as shown on the Flood Insurance Rate Map for buildings in the Special Flood Hazard Area are as follows in the table below.
The best flood protection method is elevation (measured to the top of lowest floor in A Zones, to the bottom of lowest horizontal structural member in V Zones) but dry floodproofing to the minimum elevation is allowed for non-residential buildings. Please refer to City Code of Ordinance §27-117.
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.
What to Do Before a Flood
Determine if your property is located in an area subject to flooding
Keep an emergency supply
Maintain drainage channels and pipes free of obstruction and debris
Meet improvement requirements
Meet permitting requirements
Protect your property from the hazards of flooding and wind
Purchase flood insurance on your property (Note: there is a 30-day lag time from the time of application)
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.
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:
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.