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San Marino, CA Radon Levels

Check local San Marino radon levels and find certified testing and mitigation professionals to keep your home safe


San Marino, CA Radon Facts

EPA Radon Zone Zone 2 — Moderate Risk 2–4 pCi/L (Zone 2)
County Los Angeles County, CA
Zip Code 91108

Nestled in Los Angeles County within the San Gabriel Valley, San Marino sits on alluvial fan deposits from the nearby San Gabriel Mountains. Testing data for zip code 91108 is currently insufficient to determine community radon averages. This affluent community's housing stock, featuring many large homes built throughout the 20th century with varied foundation types, may experience different radon levels depending on construction details and proximity to mountain-derived sediments.

San Marino, CA Radon Mitigation

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

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Radon FAQ for San Marino, CA

What EPA Radon Zone is San Marino in?
San Marino and the 91108 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 San Marino?
Radon mitigation in San Marino 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 San Marino?
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