Radon Testing: What You Need to Know

Radon Testing: What You Need to Know

Why Test?

Nearly 1 out of every 15 (or about 6 million) homes in the United States is estimated to have elevated radon levels. While it may appear that the chance is relatively low that your home has a radon problem, you won’t know until you test. Also, certain areas of the country have higher radon potential than others.

Testing for radon is easy and only takes a few minutes of your time.
There are many kinds of low-cost “do-it-yourself” radon test kits available through the mail or from some retail outlets. Click here for a low cost radon test kit coupon, made available through the National Safety Council’s Environmental Health Center. Click here for a low cost radon test kit coupon, made available through the National Safety Council's Environmental Health Center.
Establishing that your home does not have a high radon level or that you have reduced the radon level is a good selling point when you sell your house.

Types of Tests: Short-Term versus Long-Term Tests

The quickest way to test is with a short-term (2 – 90 days) test. Most short-term tests are 2-7 days in duration.
Longer term tests are available that take 91 days or longer.
For a low cost radon test kit coupon from the National Safety Council's Environmental Health Center, click here.
For information about radon or how to test for it, call the National Radon hotline at 1-800-SOS-RADON.
You can also hire a professional radon tester to test your home. Professional testers may use equipment that provides continuous monitoring. As a first step, you should contact your state radon office for information about certification requirements for your state. CFA Foundation recommends that you use a tester certified by a private radon proficiency program such as the National Environmental Health Association National Environmental Health Association or the National Radon Safety Board.

Testing Options

You can conduct a do-it-yourself radon test or hire a company to test your home for radon.

Do-It Yourself Kits: Radon test kits are available at home improvement and hardware stores. You can also purchase a reduced price test kit from the National Safety Council Environmental Health Center's Radon Hotline at 1-800-SOS-RADON. Click here for a low cost Radon Test Kit Coupon from the National Safety Council's Environmental Health Center.

Professional Testers: Contact your state radon office to see if they have specific requirements for radon testers in your state. If your state does not have specific requirements for radon testers, we strongly recommend that you use a tester who is certified by the National Environmental Health Association National Environmental Health Association or the National Radon Safety Board.

Hiring a professional radon tester will be more expensive than the do-it-yourself alternative. If you are involved in a real estate transaction, hiring a professional tester can have its advantages over self-testing. Any test performed for a real estate transaction should include steps to prevent or detect test interference. Professional radon testers have ways to detect and prevent test interference so that you can have the utmost confidence in your test results.

When to Test

You can perform a radon test any time of year. EPA recommends conducting short-term radon tests using closed-building conditions, regardless of the time of year. Closed building conditions will generally exist as normal living conditions in northern areas of the country when the average daily temperature is low enough so that windows are kept closed. Depending on the geographical area, this can be the period from late fall to early spring. When it is necessary to make measurements during mild weather, additional measures should be taken to ensure that closed-building conditions are maintained during short-term tests.

Radon levels can vary significantly between seasons. For example, indoor radon concentrations can be higher during colder weather, due to a larger pressure differential between indoors and outdoors leading to a higher rate of radon entry.

Long term radon tests give a better estimate of the year-round average radon level. The closer the measurement is to 365 days, the more representative it will be of annual average radon levels.

Preparing to Test Yourself

For short-term tests, establish closed-building conditions by keeping all doors and windows closed for 12 hours prior to taking the test, and as much as possible during the test. This is not necessary for long term tests; normal lived-in conditions are adequate. You do not have to vacate your home while testing. Normal entry and exit from the house are acceptable during testing.
Place the radon test kit in the lowest lived-in level of the home (for example, the basement if it is frequently used, otherwise, the first floor).
Place the test kit in a room that is used regularly, but not the kitchen, bathroom, or laundry room. For exact placement, follow the instructions that come with the test kit.

Interpreting Radon Test Results

Radon test results are reported in picocuries per liter (pCi/L), which is a unit of radiation measurement that indicates the concentration of radon gas in your home.

EPA recommends that homeowners with a level of 4 pCi/L or higher reduce these levels of radon in their homes.
If you use a short-term test, EPA recommends that you do a follow-up test and average the two results. You can also perform two simultaneous side-by-side short term tests and average the results. When the average of two short-term tests or the results of a single long-term test (greater than 90 days) meets or exceeds the action level of 4 picocuries per liter, then mitigation is recommended to achieve lower levels of radon in the home.
If your radon test results are 4 pCi/L or higher, then you should take steps to reduce your family’s risk.
You may also want to consider taking steps to reduce the radon level if the test results are between 2 and 4 pCi/L.

For more detailed information about the types of tests and testing procedures, consult the EPA's publications A Citizen's Guide to Radon at