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Radon Information and Data

Radon Test Kit

Radon is a cancer causing, radioactive gas that you cannot see, smell, or taste. The U.S. Environmental Protection Agency (EPA) estimates that it is the second leading cause of lung cancer in the U.S. and the number one cause of lung cancer among non-smokers.

U.S. Surgeon General's National Health Advisory

Indoor radon is the second leading cause of lung cancer in the United States and breathing it over prolonged periods can present a significant health risk to families all over the country. It's important to know that this threat is completely preventable. Radon can be detected with a simple test and fixed through well-established venting techniques."

- January 2005.

According to EPA, radon comes from the natural (radioactive) breakdown of uranium in soil, rock, and water and gets into the air you breathe. It finds its way into homes through cracks and holes in the foundation, construction joints, and plumbing fixtures.

Radon has also been found in private well water in areas with rocks that contain uranium or radium. If radon is in your well water, it may enter your home and the air you breathe when the water is used for showering and other activities around the house. Water containing radon is typically not a problem in homes served by public water systems.

For more information about radon in water, call EPA's Drinking Water Hotline at 1-800-426-4791.

Breathing in radon can change the cells in your lungs which increases your chances for getting lung cancer. EPA estimates that radon causes more than 21,000 lung cancer deaths in the United States each year. EPA also states that smokers who are exposed to radon have a much higher risk of lung cancer.

Any home can have a radon gas problem.
The only way to determine if your home is trapping radon is to test.

Order a Free Short-Term Test Kit!

You can request a free short-term test kit from DHEC, purchase a test kit from the National Radon Program or most home improvement stores, or you can hire a Certified Radon Measurement Provider.

How do I test my home?

There are two types of radon tests:

  • Short-term tests offer a quick and cheap way to test for radon. Short-term tests take from two to 90 days (depending on the device used). Once the test kit is submitted to the laboratory, lab results usually take two to four weeks to be received. Keep in mind that test results can only measure the radon levels in your home during the test period.
  • Long-term tests stay in place for more than 90 days. The results from a long-term test give a better picture of your family's actual radon exposure.

What do radon test results mean?

The amount of radon in your home is measured in pico Curies per liter of air (pCi/L). The EPA recommends that there be no more than 4 pCi/L of radon in your home. This is referred to as the "action level." The action level is the point where the risk of radon exposure justifies the cost of repairs. Because there is no completely safe level of radon, the EPA also recommends that you consider fixing your home if you find radon levels between 2 and 4 pCi/L.

If you make any structural changes or living pattern changes (for example, you move to a lower level of your home) you should retest.

EPA Recommendations for Home Testing

Step 1. 

Conduct a short-term radon test. If the result is 4 pCi/L or higher, conduct a follow-up test.

Step 2. 

Follow up with either a long-term test or a second short-term test.

  • For a better understanding of your year-round average radon level, use a long-term test.
  • If you need results quickly, use a second short-term test.

The higher your initial short-term test result, the more certain you can be that you should use a short-term rather than a long-term follow up test. If your first short-term test results were high and you need results quickly, use a second short-term test. If your test result is more than twice EPA's 4 pCi/L action level, you should use a second short-term test immediately.

Step 3. 

  • If you followed up with a long-term test: Fix your home if your long-term test result is 4 pCi/L or more.
  • If you followed up with a second short-term test: The higher your short-term results, the more certain you can be that you should fix your home. Consider fixing your home if the average of your first and second test is 4 pCi/L or higher.

How can I reduce radon in my home?

There are methods to prevent radon from entering your home and other methods that reduce radon after it is inside. To develop the right plan for your home, EPA recommends hiring a Certified Mitigation Provider and possibly obtaining estimates from more than one provider.

As a courtesy (not an endorsement) DHEC provides a list of Certified Mitigation Providers that are located in South Carolina.

You may also find contractors through the two national certification programs (National Radon Safety Board or American Association of Radon Scientists and Technologists, Inc. (AARST) National Radon Proficiency Program (NRPP)).

Some radon reduction systems can reduce radon levels in your home by 99 percent and most homes can be fixed for about the same cost as other common home repairs. Cost will vary with the reduction method you choose, the size of your house, how your home was built, and many other factors.

Are you building a new home or are you a builder who is interested in building homes with radon resistant new techniques?

According to EPA, builders and contractors provide a public health service when they build radon-resistant new homes because they help to reduce residents' risk of lung cancer from exposure to radon. EPA also states that the cost of radon resistant building is typically less than the cost to mitigate after construction. DHEC's Building Radon Out brochure is a great resource for home buyers who have purchased or are looking to purchase a new home that was built with the features of radon-resistant construction.

All new homes should be tested after you move in. More information about radon resistant techniques is available on EPA's website.

EPA has also developed a Home Buyers and Sellers Guide as a resource if you are interested in buying or selling a home.

Note: DHEC's free radon test kits are not approved for real-estate transactions.

EPA's Radon Zones map shows the areas in the country, including South Carolina, with the highest potential for elevated indoor radon levels. EPA, however, recommends that all homes be tested for radon regardless of geographical location as homes in all three "zones" have been found to trap radon.

View a map of S.C. test kit result averages by county. This map is current through December 31, 2015.

S.C. DHEC Publications

EPA Publications

Other Helpful Web Sites

Useful Telephone Numbers

  • National Radon Hotline: Purchase radon kits by phone
    • 1-800-767-7236
  • National Radon Helpline: Get live help for your radon questions
    • 1-800-557-2366
  • National Radon Fix-It Line: For general information on fixing or reducing the radon level in your home
    • 1-800-644-6999
  • National Radon Hotline En EspaƱol
    • 1-866-528-3187
  • SCDHEC Radon Program Toll-Free Number
    • 1-800-768-0362