Radon Program (Indoor Radon)
The Indoor Radon Program, within the Environmental Management Branch, seeks to reduce the health risk from radon exposures by increasing awareness, providing information about testing, identifying areas of high radon potential, and promoting mitigation and radon-resistant construction.
What's New
What is radon?
Radon is a naturally occurring radioactive gas. It is released during the natural decay of uranium, which is found in most rock and soil. Its occurrence in the state is influenced primarily by geology. Click here to find out more about radon.
Where is radon found?
Although certain areas of the state are more likely to encounter radon problems than other areas, radon is a house-to-house issue. You may live in an area of low radon potential yet your house can have elevated radon while your neighbor's house has no radon.
Radon is odorless, invisible, and without taste, and cannot be detected with the human senses. The only way to detect it is to test for it. For information on home test kits, click here.
Testing during real estate transactions must be conducted by a California certified radon tester. If your tester is not on our list, he or she is not certified.
How does it get into my house and what can I do?
Air pressure inside your home is usually lower than pressure in the soil around and under your home. Because the pressure is lower inside, radon is sucked into your house through cracks or holes in the slab or foundation (more about how radon gets into your house). If you have elevated radon levels you can fix your home. CDPH along with U.S. Environmental Protection Agency (US EPA) recommends that you fix your home if it has 4 picocuries per liter (4 pCi/L) or higher. If you are building a house in an area of moderate or high radon potential, we recommend using radon-resistant building techniques.
Why do I care about radon?
Radon is the second leading cause of lung cancer (PDF)
, following smoking. US EPA estimates (PDF)that nationally 21,000 lung cancer deaths are caused by radon each year.
For more information
Questions? Call the toll-free radon message line at 1-800-745-7236, or contact
California Department of Public Health
ATTN: George Faggella, George.Faggella@cdph.ca.gov; (916) 449-5674; Fax (916) 449-5665
Indoor Radon Program, MS 7405
1616 Capitol Avenue, 2nd Floor
P.O. Box 997413
Sacramento, CA 95899-7413