Call For A Free Quote: 1-800-299-3578 (toll free)

Diamond Bar, CA Radon Levels

Check local Diamond Bar radon levels and find certified testing and mitigation professionals to keep your home safe


Diamond Bar, CA Radon Facts

EPA Radon Zone Zone 2 — Moderate Risk 2–4 pCi/L (Zone 2)
County Los Angeles County, CA
Zip Code 91765

Nestled in the foothills of Los Angeles County within the greater Los Angeles Metro, Diamond Bar features suburban developments built primarily from the 1960s through 1990s on sedimentary soils. Most homes in zip code 91765 utilize slab-on-grade construction typical of Southern California, though some hillside properties have partial basements. While radon testing data is limited for this community, California's variable geology makes professional testing a wise precaution for all homeowners.

Diamond Bar, CA Radon Mitigation

Professional radon mitigation is the most effective way to permanently lower radon levels and protect your household.

Need Radon Mitigation or Testing in Diamond Bar?

  • 100% Free, No-Obligation Quotes
  • Matches You with State-Licensed Los Angeles County Pros
1-800-299-3578 Toll-free · Mon–Fri 8am–6pm ET

Radon FAQ for Diamond Bar, CA

What EPA Radon Zone is Diamond Bar in?
Diamond Bar and the 91765 zip code are in Los Angeles County, which has an EPA assigned Radon Zone of 2. A zone of 2 predicts an average indoor radon screening level between 2 and 4 pCi/L.
How much does radon mitigation cost in Diamond Bar?
Radon mitigation in Diamond Bar typically costs between $800 and $2,000. Most homes with standard basements can be mitigated with a sub-slab depressurization system in the $1,000–$1,500 range. Factors that can increase cost include complex foundations, crawl spaces, or very high radon levels.
Should I test for radon if I'm buying a home in Diamond Bar?
Yes. Radon testing should be part of every home purchase. A short-term radon test is typically included as part of the home inspection process and costs $150–$250. If elevated levels are found, you can negotiate mitigation as part of the sale.

Most Active Radon Markets in California

Cities in California with the most user-submitted radon test data, ranked by number of submissions.

CityAvg User Radon LevelSubmissions
Los Angeles 7.83 pCi/L 6
Mammoth Lakes 10.80 pCi/L 5
San Jose 4.20 pCi/L 5
Rancho Palos Verdes 8.00 pCi/L 4
Bishop 6.25 pCi/L 4
Oakland 5.00 pCi/L 4
Woodland Hills 7.67 pCi/L 3
South Lake Tahoe 6.33 pCi/L 3
Palos Verdes Peninsula 6.00 pCi/L 3
Sacramento 4.33 pCi/L 3