Radon Frequently Asked Questions

General Questions

1. What Is Radon?

Radon is a naturally occurring, radioactive gas that you can’t see, taste or smell. It is produced by the breakdown of uranium in soil, rock and water. High levels of radon have been found in all 50 states. Indoor radon is the second leading cause of lung cancer after smoking. Radon contributes to an estimated 7,000 to 30,000 lung cancer deaths each year. A combination of smoking and high levels of radon in your house increases your risk.

2. How Does Radon Get Into My Home?

Radon enters homes most commonly through:

  • cracks in foundations;
  • openings around sump pumps and drains;
  • construction joints;
  • cracks in walls;
  • crawl spaces; and
  • in some cases from well water.

Radon is usually most concentrated in the lowest level of the home. Radon may also be present in well water and can be released into the air in your home when water is used for showering and other household uses. Radon entering homes through water may be a small risk compared to radon entering though the soil.

3. Is Radon Really A Problem?

According to the U.S. Environmental Protection Agency (EPA), radon contributes to an estimated 7,000 to 30,000 lung cancer deaths per year. The Surgeon General, the EPA, the National Academy of Sciences, the American Medical Association, the World Health Organization and the American Lung Association have all identified indoor radon as a national health problem. EPA recommends that all homes and apartments below the third floor be tested. As with all pollutants, there is some uncertainty in estimating health risks associated with radon. Because radon risk estimates are based primarily on scientific studies of humans, scientists are considerably more certain of radon risk estimates than they are of estimates based solely on animal studies. Smoking increases the risk of exposure to radon, by as much as 10-15 times.

4. What Health Effects Are Associated With Exposure To Radon? 

An increased risk of lung cancer is the primary health effect associated with exposures to elevated radon levels. When radon decays within your lungs it releases energy that can damage lung tissue and lead to lung cancer over the course of your lifetime. Not everyone exposed to elevated levels of radon will develop lung cancer. Your chances of getting lung cancer from radon depend mostly on:

  • How much radon is in your home.
  • The amount of time you spend in your home
  • Whether you are a smoker or have ever smoked.

5. I understand that radon is a concern in some areas but not in others. Does my area have a radon problem?

Houses next door to each other can have very different levels. The only way to know if your house has an elevated radon level is to test. Therefore, it is recommended that all residences  be tested for radon.

6. Is Radon A Problem In Drinking Water Supplies?

Radon can enter a home through private well water. It can be released into residences when the water is run. Generally, radon is not a concern with public drinking water systems.  Compared to radon entering homes through soil, radon from water is generally a small source of risk. Contact EPA’s Safe Drinking Water Hotline for additional water safety information 800/426-4791.

7. Is radon a problem in schools?

Schools are at risk from radon just as homes are. Virginia statute requires all schools to have tested for radon, and to maintain records of the test results for disclosure on request. The regulation does not require schools that find a problem to mitigate according to a mandated schedule. It is up to the District and its constituents to address mitigation issues. Further information on how to test for radon in schools may be found in this EPA approved ANSI/AARST school testing guidance standard.

8. Where Can I Obtain More Information?

VDH Radiological Health Hotline:1-800-468-0138
EPA Safe Drinking Water Hotline:1-800-426-4791
EPA Radon Fix-it Hotline: 1-800-644-6999

EPA Radon Publications

Questions on Testing for Radon

1. How Do I Test My House?

Testing for radon is simple and inexpensive. There are many do-it-yourself kits you can buy at retail outlets or through the mail. (See next question for where to get a test kit.) EPA recommends placing the radon kit in the lowest lived-in level of the home. Follow the instructions that come with the test kit. After the test is complete, you send it to the manufacturer for analysis. The quickest way to test is with a short-term test. The EPA recommends that if the initial screening result was from 4.0 pCi/l to 9.9 pCi/l, a second test of long-term duration should be taken and used as the basis for determining mitigation. If the first test was 10.0 pCi/l or above, a second test of short term duration should be taken and the average between the two used as the basis for evaluating the situation. Virginia recommends long-term testing whenever possible.  A long term device (such as a alpha track) which stays in the home for one year is the most accurate way to determine the home’s year-round average radon level. Shorter term tests might be influenced by seasonal fluctuation and weather. Most homes test at their highest radon levels in the winter and their lowest levels in the summer. Therefore, avoid taking your initial test during the summer months if possible. You should also try to avoid testing during a long lasting severe storm because those conditions could cause temporary higher than normal radon levels in some homes. You may also hire a certified company to test your home for you. Make sure the company’s tester is listed with either the National Radon Proficiency Program (NRPP) or the The National Radon Safety Board (NRSB).

2. Where can I buy a test kit?

Test kits are sometimes available from building supply stores and also directly from several different commercial vendors.  You can purchase either short-term (2-6 days, $10-15 each) or long-term (91-365 days, $25-35 each) test kits. Long term test kits are rarely available in stores but are available from several on-line vendors. Choose a test kit that is approved by either NRPP or NRSB.

3. My neighbor has tested and found an elevated radon level (or found a very low radon level) does this mean I should (or shouldn’t) be concerned? 

No. Having a neighbor that has tested high (or low) for radon is no guarantee that your house will test similarly. The only way to know if a house has a high level of radon is to test.

4. What do these results mean?

Radon is measured in picocuries per liter of air (pCi/l). The average indoor level is 1.3 pCi/l and about 0.4 pCi/l is normally found in the outside air. EPA recommends that action be taken to reduce the indoor radon levels that are 4.0 pCi/l or above. Most homes today can be reduced to 2 pCi/l or below. Any level of radon exposure carries some risk.

5. Are Radon Testing Kits Accurate? 

NRPP or NRSB approved test kits, when used as directed, provide reliable indications of radon concentrations over the time the kits are used. Proper test conditions are essential for good measurements. For short term tests, key elements are: 12 hrs. of closed house conditions before beginning the test, and for the duration of the test; a minimum 48 hour test period; placing the test device in the lowest occupied level of the home; placing the device at least 20 inches off the ground and keeping the device well away from any fans or any source of high heat or humidity. Be sure to test a room that is frequently occupied (like a bedroom or family room).

6. When Should Short-Term Tests Be Conducted? Does Time Of Year Matter?

Winter readings are typically higher than those taken in summer. During winter, the larger differential between outdoor and indoor pressure is likely to lead to higher entry of radon into a house than would occur in summer. In addition, your home is likely to be less ventilated in the winter. EPA recommends testing in the winter.

7. Why Should I Perform A Long-Term Test Rather Than A Short-Term Test That Gives Me Quicker Results?

A year long test takes into consideration seasonal variation, which can be substantial and therefore provide a better measure of the true, annual average radon exposure than a short-term test. The short-term kits provide a good indicator of whether additional testing is warranted. If a short-term test result is greater than 4.0 pCi/l or greater, EPA recommends following up with a long-term test, or a second short-term test, to confirm the result.

8. If I want a professional to test my home, where do I obtain a list of approved testers?

NRSB or NRPP listed radon testers within Virginia can be obtained directly with each certification’s program web site, NRSB  and NRPP

Questions on Radon Reduction

1. I tested my home and found a radon level of just under 4 pCi/l. Is that safe?

Four picocuries per liter of air has been identified by EPA as the recommended action level. There is no absolutely safe level; there is some level of risk associated with all levels of radon. EPA estimates that for a 70 year exposure at an annual average of 4 pCi/l of radon, the risk or lung cancer is 7 per 1,000 persons exposed for non-smokers, and 62 per 1,000 persons exposed for current smokers.

2. I tested my home and found a radon level higher than 4 pCi/l. What should I do?

The EPA recommends that if the initial screening result was from 4.0 pCi/l to 9.9 pCi/l, a second test of long-term duration should be taken and used as the basis for determining mitigation. If the first test was 10.0 pCi/l or above, a second test of short term duration should be taken and the average between the two used as the basis for evaluating the situation. A long term test taken over an entire year is the most accurate way to determine a home’s average radon level. For more information on testing, see EPA’s brochure “Home Buyer’s and Sellers Guide to Radon”. For more information on fixing a home with high radon levels, see EPA’s brochure “Consumer’s Guide to Radon Reduction”.

3. Should I sell my house if it has a high radon concentration? Should I refuse to buy a new house with a radon problem?

Radon reduction is comparable to other home maintenance efforts. If there is a radon problem in a particular residence, it is almost always fixable and usually costs between $800 and $2,500.

4. What is involved in reducing the radon level in my home? What will it cost?

Several different methods are used to reduce radon levels in homes. The most common is a combination of sealing cracks and openings which prevents the radon from getting into the home; and reversing the flow of radon entry by depressurizing the material under the foundation. In most cases, elevated radon levels can be reduced below 2 pCi/l. See the EPA brochure: “Consumer”s Guide to Radon Reduction” The cost for a professionally installed radon reduction system typically ranges from $800 to $2,500.

5. Where can I obtain a list of certified contractors to mitigate my radon problem?

A list of NRPP or NRSB certified radon mitigators within Virginia can be obtained from each organization’s web site: NRSB  and NRPP.

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