California Radon Information
California Radon Program:
Radon Website: WebsiteRadon Contact: Radon Program Manager
Active Radon Program: Yes
Require License for Radon Professionals: Yes
California Radon Levels
California has a user submitted radon level of 5.91. This is based on data submitted from visitors on our site. Learn more here.
EPA Radon Levels
California has 58 counties and 2 (3%) have been assigned Zone 1 counties by the EPA. Zone 1 counties have the highest potential to have homes test higher than 4 pCi/L. California's state radon zone average is 2.43, which is the average of all county zone ratings the EPA has assigned the state, ranking it 40 among all states.
The radon levels in the state of California are about average. However there is an increased risk for all homeowners, which is why we recommend testing exposure levels at least twice a year.
California Radon Mitigation and Testing
Need your home tested for radon? Already know you have high levels and need a radon reduction system installed? Finding qualified radon professionals can be difficult, but we've put together a list of California contractors to help you save time.
California Radon Mitigation
We have compiled a list of qualified radon mitigation contractors.
Find Radon Mitigation Contractors here
California Radon Testing
Need your home or office tested for radon? We have compiled a list of qualified radon testing contractors.
Find Radon Testing Contractors here
California Radon Map
Zone 1 (1): Potential for radon levels above 4 pCi/L according to EPA
Zone 2 (2): Potential for radon levels between 2 pCi/L and 4 pCi/L according to the EPA
Zone 3 (3): Lowest EPA level with expected radon levels at or below 2 pCi/L
Disclaimer: It is strongly recommended that all households, schools and office spaces test radon levels individually. The EPA Radon Zone data is not an indicator of individual test results, but a guideline for strategic planning. Toxic radon levels can be found in all counties, regardless of their zone rating. While we make efforts to keep this information up to date, it is derived from thirdparty sources which may not be accurate or reflect the most current statistics.
About California
California is the most populous state with 38 million people, or every one out of eight Americans. It is also the third largest state by surface area in the country, right behind Alaska and Texas.
Residents of the Alpine, Mono and Inyo counties are being offered free radon testing kits from the California Department of Public Health in association with the US EPA, CDPH and California Geological Survey. If you live in one of the aforementioned counties it is recommended that you take the opportunity to acquire a testing kit. The free test kits do include mailing supplies and an analysis of the test results.