How Do You Test for Radon?

With a test kit. The EPA's Citizen's Guide to Radon says testing is the only way to know if you are at risk from radon, and that the EPA and the Surgeon General recommend testing all homes below the third floor. CDC says there are two general types of radon test kits, short-term kits that measure radon for 2 to 90 days for quick results, and long-term kits that measure for over 90 days and tell you the home's year-round average level, and that the longer the test, the better the results will reflect your home's radon levels and your lifestyle.

Placement matters. The guide says to put the test kit in the lowest lived-in level of the home, such as the basement if it is frequently used, otherwise the first floor, in a room that is used regularly but not the kitchen or bathroom, and at least 20 inches above the floor. The EPA says that if your living patterns change and you begin occupying a lower level of your home, such as a basement, you should retest on that level.

If a short-term test shows radon higher than 4 pCi/L, CDC says to take a second test, either short-term or long-term, and to average the two results if the second test is also short-term. CDC reports that the EPA recommends contacting a licensed professional to install a radon reduction system if your level is at or above 4 pCi/L, and taking action to reduce radon from 2 through 4 pCi/L, and says there is no known safe level of radon.

The EPA says radon test kits are available from several sources, and that free test kits are sometimes available from local or county health departments or from state radon programs. To find a qualified professional to test or fix a home, it says to contact your state radon program.