Flood Information

Major Topics


Frequently Asked Questions
Flood Preparedness
Preparation and Recovery
Flood Safety Tips
National Weather Service Automated Flood Warning Systems (Data from Fairfax County water level and rain gauges)
Past Events (Belle Haven and Cameron Run)
Flood Risk Management Study Status Update for Belle View/New Alexandria/River Towers

 What Can I Do To Protect My Property?

Residents can help protect their property from the effects of flooding through such measures as regrading the lot, waterproofing the structure or raising the level of the building. Information about protecting buildings is available at FEMA's Safer, Stronger, Protected Homes & Communities and Homeowner's Guide to Retrofitting websites. Property owners may be interested in the National Flood Insurance Program for more information on purchasing flood insurance.

Any alteration to a building or land, including re-grading, filling or modifying a sewer line, requires a permit. For more information regarding building and site modifications, call Land Development Services at 703-324-1720, TTY 711.

Residents can help prevent flooding by keeping storm drains clear of trash and debris. Litter blocking storm drains may cause flooded streets, traffic delays and property damage. Please use the storm drain flooding report form to notify the county of blocked storm drains. 

Additional Information:

Flood Protection Information Newsletter, September 2017

What Is a Floodplain?

In general, a floodplain is the flat area located adjacent to the main stream channel. When stream banks overflow during or after a storm, the floodplain provides natural storage for the excess water.

There are three distinct kinds or categories of floodplains in Fairfax County, each of which carries different development restrictions. These three categories are:

  1. Minor Floodplain: drainage area greater than 70 acres but less than 360 acres.
  2. Major Floodplain: drainage area 360 acres or greater.
  3. Those which are designated as a floodplain by the National Flood Insurance Program.

For further information about defining floodplains, please see the Zoning Ordinance, Article 20, Definitions.

Special Flood Hazard Areas

Special Flood Hazard Areas are high risk areas that have a one-percent chance of be inundated by a base flood in any given year as identified by the National Flood Insurance Program maps. Floodplain management regulations must be enforced and mandatory purchase of flood insurance applies for these areas. For more information, please visit FEMA's Special Flood Hazard Area website or see the Special Flood Hazard Area Maps.

Additional Information:

Floodplains Frequently Asked Questions
Floodplain Management Plan Progress Report, September 2017
Northern Virginia Hazard Mitigation Plan

 Building In and Around a Floodplain

Activities in the floodplain are regulated by the Fairfax County Zoning Ordinance, Article 2-900, and may require written approval from the Department of Public Works and Environmental Services or a Special Exception approval by the Board of Supervisors. If you have question about floodplain regulations, call the Engineer of the Day at 703-324-1575, TTY 711.

Information regarding applications for Special Exception approval for uses in the floodplain is available from the Zoning Evaluation Division, Department of Planning and Zoning, 12055 Government Center Parkway, Suite 801, Fairfax, VA 22035-5504, or by calling 703-324-1290, TTY 711.

 National Flood Insurance Program

National Flood Insurance Program

Most homeowner insurance policies do not cover damage caused by flooding. The National Flood Insurance Program was created to enable property owners in participating communities, including Fairfax County, to purchase flood insurance protection. Properties that have been officially identified as being in a Special Flood Hazard Area and that have a federally backed mortgage are required to participate in the National Flood Insurance Program. However, the program is available to all property owners, including owners of properties that have been flooded and properties located outside of Special Flood Hazard Areas.

Flood insurance policies that have been purchased as a bank or lender requirement, or in order to obtain a mortgage or home improvement loan, may cover the structure but may not cover the contents of the property. Property owners should review and discuss their policy with their insurance carrier to ensure their needs are adequately covered.

Additional information is available on the FEMA National Flood Insurance Program website, by calling 1-800-427-4661, or by writing to: Federal Emergency Management Agency, 500 C Street SW, Washington, DC 20472. 

Community Rating System

The Community Rating System is a voluntary program for recognizing and encouraging community floodplain management activities that exceed the minimum standards set up for the National Flood Insurance Program. The program does this by adjusting flood insurance rates to reflect the reduced flood risks that are a result of community activities that reduce flood losses, facilitate accurate insurance ratings and promote awareness of flood insurance.

Fairfax County has participated in the program since 1993, and is one of two Class 6 jurisdictions in the commonwealth of Virginia. With this improved rating, residents may obtain flood insurance on properties in Special Flood Hazard Areas (SFHAs) at a twenty percent discount on their flood insurance premiums. Owners whose properties are not in SFHAs, receive a ten percent discount. For more information, please see the FEMA Community Rating System website.

Additional Information:

Flood Protection Information Newsletter, September 2017

 Dams and Dam Safety    

There are a number of large dams in Fairfax County; some are privately owned, and others are owned or maintained by the county or other public entities. There are many small, man-made ponds or impoundments, some of which include dams as part of the structure. For more information on dams, please see the dam basics website.

Any development proposed within the mapped dam break inundation zones of state regulated dams must be identified on all preliminary plats, subdivision plans, site plans and minor site plan submissions. More information, including maps, can be found in the Development in Dam Break Inundation Zones website.


For additional information, please email the Stormwater Planning Division or call 703-324-5500, TTY 711.

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