CALIFORNIA - EPA Map of Radon Zones The purpose of this map is to assist National, State and local organizations to target their resources and to implement radon-resistant building codes. This map is not intended to determine if a home in a given zone should be tested for radon. Homes with elevated levels of radon have been found in all three zones. All homes should be tested, regardless of zone designation. http://www.epa.gov/radon/zonemap.html ~ EL NORTE MENOOCIH IMPORTANT: Consult the publication entitled "Preliminary Geologic Radon Potential Assessment of California" (USGS Open-file Report 93-292-1) before using this map. See http://energy.cr.usgs.gov/radon/grpinfo.html This document contains information on radon potential variations within counties. EPA also recommends that this map be supplemented with any available local data in order to further understand and predict the radon potential of a specific area. SAN FRANCISCO Zone 1 Zone 2 Zone 3 SISKIYOU MODOC TRIN ITY { SHASTA LASSEN TEHAMA PLUMAS GLENN BUTTE COLU SONOMA NAPA YOLO DORADO LANO ALPINE CONTRA COSTA CALA- JOAQUI SAN MATEO SANTA \ STANISLAUS CLARA POSA SANTA CRUZ MADERA SAN BENITO FRESNO MONTEREY TULARE KINGS INYO KERN SANTA BARBARA SAN BERNARDINO VENTURA LOS ANGELES ORANGE R VERS DE SAN LUIS OBISPO SAN DIEGO IMPERIAL | ------- |