Department of Emergency Management and Security

CONTACT INFORMATION: Open during regular business hours 8 a.m. - 4:30p.m., Monday - Friday
4890 Alliance Drive, Suite 2200, Fairfax, VA 22030
Seamus Mooney

Coastal Flooding

What It Is

Fairfax County has miles of shoreline and wetlands along the tidal Potomac River, which leaves several communities susceptible to tidal/coastal flooding. In fact, coastal flooding can happen on sunny days. Tidal anomalies, tropical systems, nor’easters, and even onshore winds can lead to flooding of property, streets, and homes in low-lying communities in eastern Fairfax County.

Coastal Flooding Annex Image

Coastal Flooding Hazard Annex

Click on the appropriate link below to download a PDF copy of the Coastal Flooding Hazard Annex page from the Community Emergency Response Guide.

English (PDF)

Key Terms


  • A Coastal Flood Watch is issued when moderate to major coastal flooding is possible. Such flooding would potentially pose a serious risk to life and property.
  • A Coastal Flood Advisory is issued when minor or nuisance flooding is occurring or imminent.
  • Coastal Flood Warning is issued when moderate to major coastal flooding is occurring or imminent. This flooding will pose a serious risk to life and property.
  • Riverwatch is a Fairfax Alerts subscription list designed specifically to provide information to flood prone areas along the Potomac River, such as Huntington, Belle View, & New Alexandria.
  • Tides are the alternating rising and falling of the surface of the ocean and of water bodies connected to the ocean that occurs usually twice each lunar day as a result of gravitational forces.
  • Tide tables, or tide charts, list the predicted times and heights of high and low tide for a specific location.
  • Storm Surge is an abnormal rise of water generated by a storm, over and above the predicted tides.

What To Do

  • Sign up for Fairfax Alerts, including Riverwatch, and have a battery or crank powered NOAA weather radio available.
  • Know if your residence or business is in or near a floodplain.
  • Know your risk: Fairfax County has tidal flood inundation maps available online.
  • Assemble an evacuation kit and have a plan. Decide early whether you will evacuate, and where you will go if ordered to or opt to leave, including a plan for your pets.
  • Disconnect electrical appliances, elevate or move your furniture, valuables, and important documents, to the highest floor of your house. · Elevate and anchor critical utilities, including electrical panels, appliances, and heating systems.
  • Monitor National Weather Service forecasts and tide times.
  • Apply for flood insurance. Consider this even if you are not in the 100-year floodplain (the FEMA-designated “Special Flood Hazard Area”) – many recent floods have exceeded the 100-year and 500-year marks!
  • Learn First Aid.
  • Refer to “Medical Emergency” hazard pages.

  • Listen to official information and evacuate if directed.
  • Implement your emergency plan and take your emergency kit with you.
  • If you encounter rising water, move to higher ground immediately.
  • Do not touch electrical equipment if you are wet or standing in water.
  • Park vehicles out of flood prone areas.
  • Always stay clear of floodwaters.
  • Do not drive through other flooded roads, even if you have vehicle with high clearance and even if the water appears to be shallow – “turn around, don’t drown.”
  • Stay away from downed power lines to avoid the risk of shoor electrocution.

  • Return home when local officials say it is safe. Avoid walking or driving through floodwaters.
  • Be aware of areas where floodwaters have receded and watch out for debris. Floodwaters can erode roads and walkways.
  • Do not drink from floodwaters.
  • Do not drink or wash with water from a flooded household well until it is tested and found to be safe to use.
  • Eliminate standing water where mosquitoes may breed.
  • Do not eat any food that may have come into contact with flood water. “When in doubt, throw it out.”
  • Remove all porous items that have been wet for more than 48 hours and cannot be thoroughly cleaned and dried. These items can remain a source of mold growth and should be removed from the home.
  • Check in with family and friends by phone, texting, or using social media.
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