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Healthy Homes and Radon

Radon is the number one cause of lung cancer among non-smokers, according to EPA estimates, causing approximately 21,000 lung cancer deaths per year in the United States. Radon is a naturally occurring, odorless, radioactive gas formed by the breakdown of uranium found in soil, rocks beneath and around building foundations, and some building materials.

Radon is a gas and can enter homes and buildings through cracks in concrete floors and walls, the basement or crawl space, floor drains, or through well water. Any home may have a radon problem, new or old.  Radon from soil is the main source, but in rare cases radon can also be found in drinking water. Health risks from radon in drinking water are lower and are only a significant concern in certain parts of the country.

Radon in its natural state cannot be detected by human senses. Testing is the only way to know if you and your family are at risk from radon. EPA and the Surgeon General recommend testing all homes below the third floor for radon. Testing is done by using a device that is left in the home for specified period of time. It is simple and inexpensive.

A list of radon services and information on low-cost test kits for California residents can be found here.

Radon in California

Radon levels vary by geographic location. California's indoor radon program, along with California Geological Survey, is developing county-specific radon potential maps. View the list of completed maps.

To learn more about Radon: