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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.  

Test Your Home This January

January is National Radon Action Month and the cold winter months are the best time to test for this odorless and colorless gas. Upon receiving your radon test kit, you simply put the kit in your home for a few days and then mail it back for analysis. The test kits do not affect your normal household activities. In a few weeks, your home’s test results will be mailed to you.

CDPH is offering the free and discounted test kits to households in California throughout the month of January. 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. You can order the free test kits online through the California Resident Test Kit Request Portal. Supplies are very limited. Additional discounted test kits can be purchased through our partner laboratory, Alpha Energy, for $14.95.

In addition to learning of your home’s radon level, the aggregated information will be used to update statewide Radon Potential Maps, which show the likelihood of radon in a specific region.

To learn how your community can take action during National Radon Action Month, visit the EPA National Radon Action Month website.

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.

New! Statewide Indoor Radon Potential Report

The California Geological Survey has released Special Report 247: California Indoor Radon Potential (2022), which addresses the radon potential throughout the state of California. The statewide report, and all regional radon potential reports, are available upon request directly from the California Geological Survey


​​Contact the radon program at radonprogram@cdph.ca.gov (email) or 1-800-745-7236 (telephone).
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