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The Town of Sullivan's Island has partnered with Everbridge to bring you up-to-date alerts from the Police Department and the Water & Sewer Department. Registration is free and you will be alerted via text message or email. Text our zip code, 29482, to 888777 or click here to sign up today!  NOTE:  Please check with your cell phone provider for fees to receive text messages. 

Click Here to review our Stormwater Master Plan Page.

Click here to review the draft Comprehensive Plan review.

Flood Zone Designation

Is your property in a flood zone? 

Flood hazard areas are areas located within the 100-year floodplain, which are defined as any area that has a one (1%) percent chance of flooding in any given year. Smaller scale floods (50-year and 10-year) have a greater chance of occurring in any year and can pose a significant flood hazard to people and property close to the ocean, sound, drainage channels and streams. Floods larger than the 100-year event can also occur.  You should become informed as to the flood hazard potential for your property.  Click on the map below to determine your base flood elevation. To determine your properties flood zone, you may search your address for free on the Charleston County website. 


View Flood Map

The new Flood Insurance Rate Map (FIRM) became effective January 29, 2021. Most zones and flood height requirements on Sullivan's Island were reduced when these maps took effect. This resulted in lower insurance premiums. Town Staff advises residents to secure a copy of your Elevation Certificate. If you do not have one, it is advisable to contact a surveyor to develop one and send it to the Sullivan's Island Building Department as well as your flood insurance provider. The Town may already have a copy of your Elevation Certificate on file. If you would like to inquire about your Elevation Certificate please contact Jessi Gress at 843-883-5727 or

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.