Radon Facts

Why should I think about radon?

Any home can have a radon gas problem. Homes can trap radon inside where it can build up. If you breathe radon in, it can change the cells in your lungs. These changes can increase your chances for getting lung cancer. Radon is the second leading cause of lung cancer in the U.S. and the number one cause of lung cancer among non-smokers. The U.S. Environmental Protection Agency (EPA) estimates that radon causes more than 20,000 lung cancer deaths in the United States each year. If you smoke and your home has radon, your risk of lung cancer can be higher than normal. The S.C. Radon Zones map shows the areas in South Carolina with the highest potential for elevated indoor radon levels. However, the EPA recommends that all homes be tested for radon regardless of geographical location.

What is radon?

Radon is a gas. You cannot see, smell, or taste radon. It comes from the breakdown of naturally occurring uranium or radium. Radon gets into your home through cracks and holes in the foundation, construction joints, and plumbing fixtures. Radon may also enter your home in the water you use. It can be released into the air you breathe when water is used for showering and other household uses. Radon in water is generally not a problem in homes served by public water systems. It has been found in private well water in areas with rocks that contain uranium or radium. For more information about radon in water contact S. C. DHEC's Radon Hotline or EPA's Drinking Water Hotline at 1-800-426-4791.

How can I know if there is radon in my home?

The only way to know if you have a radon problem is to test your home. You can test for radon yourself. Testing is easy and should only take a few minutes. Test kits can be purchased from most home improvement stores, or you can hire a certified radon tester.
There are two types of radon tests:

  • Short-term test devices offer a quick and cheap way to test for radon. Short-term tests take from two to 90 days (depending on the device used). Lab results usually take two to four weeks. The results only measure what the radon levels were during the test period.
  • Long-term test device stays in place for more than 90 days. The results from a long-term test give a better picture of actual radon exposure
What do the radon test results mean?

The EPA says that any radon exposure carries some risk. 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. However, 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.

EPA recommendations for concerned citizens

Step 1. Take a short-term test. If your result is 4 pCi/L or higher, take a follow-up test (step 2) to be sure. If your result is less than 4 pCi/L, you may want to test again sometime in the future. If you make any structural changes or your living patterns change and you begin occupying a lower level of your home, you should retest on that level.

Step 2. Follow up with either a long-term test or a second short-term test:

  • If the initial result is between 4 pCi/L and 8 pCi/L, a long-term test should be done. This will give you a better understanding of your year round average radon level.
  • If the initial result is 8 pCi/L or higher or you need results quickly, a short-term test should be done.
    *The higher your initial short-term test result, the more certain you can be that you should take a short-term test rather than a long-term follow-up test.

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. You should consider fixing your home if the average of your first and second test is 4 pCi/L or more.

*Because there is no safe level of radon, the EPA also recommends that you consider fixing your home for radon levels between 2 and 4 pCi/L.

How can I reduce radon in my home?

There are ways to reduce the level of radon. Some methods prevent radon from entering the home. Others reduce radon after it enters the home. The cost of installing radon reduction methods depends on several factors, including how your home was built. According to the EPA, the average cost to fix a home is $1,200, but costs can range from $800 to $2,500. For more information, please refer to the contacts listed above, or call the radon hotline at 1-800-768-0362.

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

There are simple and low-cost methods that can reduce radon entry when you are building a new home. All new homes should be tested after you move in. More information about radon resistant techniques is available on EPA's website.

For training information or to find certified radon contractors and measurement providers contact:

List of Contractors (provided by DHEC as a courtesy, not an endorsement)

Buying or selling a home?

Additional Resources

2015 Youth Poster Contest

S.C. DHEC Publications

EPA Publications

Other Helpful Web Sites

Information Lines

  • National Toll Free Automated Radon Information Line: 1-800-767-7236
  • Toll Free Radon Fix-It Program: 1-800-644-6999
  • SCDHEC Radon ​Program Toll Free Number: 1-800-768-0362