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Indoor Radon Program 

The Indoor Radon Program, within the Environmental Management Branch, seeks to reduce the health risk from radon exposure by increasing awareness, identifying areas of high radon potential, and encouraging all Californians to test their homes for radon, fix their homes if they have a radon problem, and build new homes radon-resistant. Test. Fix. Save a Life.  

Radon News

Free Radon Test Kits During National Radon Action Month

January is National Radon Action Month and the cold winter months are the best time to test for this odorless and colorless gas. CDPH is offering free short-term radon test kits to households in California throughout the month of January, or until supplies run out.  Limit one per household.  The kits are provided by the U.S. Environmental Protection Agency's State Indoor Radon Grant fund, and are limited to one free test kit per household. The aggregated information from the test results will be used to update statewide Radon Potential Maps, which show the likelihood of radon in a specific region.


Order Your Free Test Kit

Order your free test kit online directly from our partner laboratory, Alpha Energy.

Para pedir en español , por favor visite Alpha Energy-esp.

 Order your free test kit by telephone by calling Alpha Energy toll-free at 1-800-324-5928 , option 6.


Using the Test Kit

Test kits will arrive within 2-4 weeks of ordering.  The test kit includes free return shipping to the laboratory for analysis.  Test results will be sent to you directly from the laboratory. Your address and any other personal information will remain confidential. Read our Test Kit Tip Sheet (PDF) to learn how to easily use your test kit. The test kit will come with detailed instructions on how to fill out the included data sheet and how to return it and the kit to the lab. Visit our Testing Information Page  to learn how to interpret results.



Please contact the radon program at 1-800-745-7326 or

Interactive California Radon Potential Map

The California Geological Survey has released an interactive web map providing radon potential information for areas of California with completed radon potential maps. Downloadable GIS data for each study area can now be downloaded through the interactive map.

​​Contact the radon program at (email) or 1-800-745-7236 (telephone).
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