Radon in California
While California may have, on average, a small percentage of houses expected to have elevated radon it has a huge population. Also there are areas of high radon potential located in densely populated areas of the state. As a result some urban areas may have large numbers of houses with elevated radon levels.
Radon Potential Maps
The Indoor Radon Abatement Act of 1988 directed the U.S. Environmental Protection Agency (USEPA) to identify areas of the United States that have the potential to produce elevated levels of radon. US EPA, along with U.S. Geological Survey (USGS) and the Association of American State Geologists, produced a series of maps and documents (EPA's Map of Radon Zones, CALIFORNIA 402-R-93-025). The full report is available upon request--contact CDPH's Radon Program.
The maps of Radon Zones identify areas of each state that have the highest potential for elevated indoor radon levels (greater than 4 pCi/L) (California map, U.S. map). The maps were designed to assist national, State and local governments and organizations to target their radon program activities and resources and should not be used to determine radon levels of a given area or house within a particular county.
California's Indoor Radon Program, along with California Geological Survey, is developing detailed radon potential maps for counties of the state. We have completed the following maps to date:
· Special Report 216 - Radon Potential in Santa Cruz County, California
Download Report (2.2 MB PDF); Download Santa Cruz County Map (3.8 MB PDF)
· Special Report 211 - Radon Potential in the Lake Tahoe Area, California
Download Report (2.3 MB PDF); Download Lake Tahoe Map (1.6 MB PDF)
· Special Report 208 - Radon Potential in San Luis Obispo County, California
Download Report (1.9 MB PDF); Download Eastern San Luis Obispo Map (5.3 MB PDF); Download Western San Luis Obispo Map (5.8 MB PDF)
· Special Report 201 - Radon Potential in Monterey County, California
Download Report (1.8 MB PDF); Download Eastern Monterey Map (1.5 MB PDF); Download Western Monterey Map (2.7 MB PDF)
· Special Report 194 - Radon Potential in Ventura County, California.
Download Report (1.8 MB PDF); Download Map (3.0 MB PDF)
· Special Report 182 - Radon Potential in Southern Los Angeles County, California.Download Report (19 MB PDF); Download Map (5.6 MB PDF)
· Radon Zone Map for Santa Barbara County
PDF, 851 KB