Radon Zone Map

All counties · California

Radon in San Diego County, California

3EPA radon zone (1 is highest)

Zone 31

The details

What the zone means
Low potential. EPA predicts an average indoor screening level below 2 pCi/L.1
Testing advice
EPA says every home should be tested, whatever the zone. Fix the home if radon is 4 pCi/L or higher and consider fixing between 2 and 4 pCi/L.1
EPA developed the zone map in 1993 and says it should not be used to decide whether a particular home needs testing. Test your home. State radon programs can help.

Sources

  1. California: EPA Map of Radon Zones, US Environmental Protection Agency, checked 1 November 2026
  2. EPA Map of Radon Zones, US Environmental Protection Agency, checked 1 November 2026

Checked 1 November 2026. "Secondary" marks a source used only because the official page could not be read.