Division of Environmental Health

CONTACT INFORMATION: Our Environmental Health Services office at 10777 Main Street in Fairfax is open during regular business hours 8 a.m. - 4:30 p.m., Monday - Friday. Clinic services are not offered at this location.
703-246-2201 TTY 711
10777 Main Street
Fairfax, VA 22030
Pieter A. Sheehan, REHS
Director, Division of Environmental Health


Protect Your Family from Radon. Radon is a gas that you can’t see, smell, or taste – but it can be dangerous. It’s the second leading cause of lung cancer. Radon is in the ground naturally. But sometimes it gets into homes through cracks in the floors or walls. Learn more by calling the National Radon Hotline: 1-800-SOS-RADON. (1-800-767-7236).The U.S. Surgeon General released a National Health Advisory on January 13, 2005, which said; Indoor radon is the second-leading cause of lung cancer in the United States and breathing it [radon] over prolonged periods can present a significant health risk to families all over the country.

Radon is a natural, radioactive gas that is colorless, tasteless and odorless. Radon is formed from the natural breakdown of uranium in the bedrock and rock used in the construction of buildings. The gas seeps up from the ground into buildings through cracks in foundations, basement walls, gaps around service pipes and sump pumps. When it is indoors, radon gas becomes trapped and accumulates in the air.

Testing your home, workplace or other normally occupied area is the only way to know for sure if an indoor radon problem exists.

For more information on radon, radon in water and consumer complaints, visit the Virginia Department of Health (VDH) Indoor Radon Program web page.

January is National Radon Action Month

Radon is a natural, radioactive gas that you can't see, taste or smell, but can be hazardous to your health.

Homes in Fairfax County are at a high risk for indoor radon and radon levels can vary from house to house. Testing your home, workplace or other normally occupied area is the only way to know for sure if an indoor radon problem exists.

Fortunately, testing is simple and inexpensive — only $3 if you are a Virginia resident.

Read more about National Radon Action Month.

Testing for Radon

Radon is measured in picoCuries per liter of air (pCi/L), a measurement of radioactivity. The U.S. Environmental Protection Agency (EPA) recommends fixing homes that have levels at or above 4pCi/L. It is estimated that 1 in every 15 U.S. homes has radon levels greater than 4 pCi/L.

Testing is simple and inexpensive. Kits can be purchased at hardware and home improvement stores. You also can hire a qualified tester to do a radon test for you. If your test results exceed 4pCi/L , a mitigation system should be installed to remove the radon gas from beneath your home.

For more information on radon testing and mitigation, and to get a coupon toward the purchase of a home test kit, visit the VDH's Indoor Radon Program web page.

Radon Potential Map of Fairfax County

Fairfax County Radon Potential MapEPA has identified the potential radon risk for the County of Fairfax as Zone 1 (High). This means the potential risk for average indoor radon screening levels would be greater than 4 pCi/l of air.

Fairfax County Health Department conducted a study of 2,142 homes during the winters of 1986-87 and 1987-88 to better characterize the relative risks in the County. They found that radon levels above the EPA action level of 4 picoCuries per liter of air can occur anywhere in the areas shown on the Fairfax County radon potential map. However, there are areas within Fairfax County where the risk of elevated radon was Low to Moderate. In the areas of low potential (yellow), 14 percent of the homes tested had radon levels that were a problem. At the other end of the radon range, only 44 percent of the homes tested in the areas of high potential (red) had elevated radon levels. This radon potential map can only provide a general guide of radon risk within Fairfax County, since homes with readings greater than and less than 4 pCi/l and be found on the same street.

Summary of the Fairfax County Health Department Radon Potential Study*

Radon Potential Radon Measured
Environmental Protection Agency Zone Homes Tested Radon Concentrations Percentage of Homes by Radon Concentration Chance of 4.0 pCi/L or Greater
Average pCi/L Median pCi/L 0 - 3.9 pCi/L 4.0 - 9.9 pCi/L 10.0 - 19.9 pCi/L 20.0 pCi/L or Greater
High 1 1086 5.5 3.5 56% 32% 8% 4% 44%
Moderate 2 497 3.2 2.4 76% 20% 4% Less than 1% 24%
Low 3 599 2.2 1.5 86% 13% 1% Less than 1% 14%

*Data from the 2,142 homes tested during the winters of 1986-87 and 1987-88

The Radon Potential of Rocks and Soil in Fairfax County, Virginia, Button, James K, et al., 1988


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