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Thousand Oaks, CA Radon Levels

Check local Thousand Oaks radon levels and find certified testing and mitigation professionals to keep your home safe


Thousand Oaks, CA Radon Facts

EPA Radon Zone Zone 1 — High Risk > 4.0 pCi/L (Zone 1)
County Ventura County, CA
Zip Code 91360
Avg. User Level 5.00 pCi/L
User Tests 1

Thousand Oaks in Ventura County sits within the Conejo Valley, where sedimentary bedrock and coastal formations create generally lower radon potential typical of Southern California. Recent testing shows an average radon level of 5.0 pCi/L, which exceeds the EPA action level of 4.0 pCi/L and warrants mitigation. The city's predominantly single-family homes built from the 1960s onward typically feature slab-on-grade construction, though elevated readings can still occur in certain geological pockets.

5.00
pCi/L average
Above EPA Action Level

Based on 1 user-submitted radon test for homes in Thousand Oaks, CA. The EPA recommends taking action at or above 4.0 pCi/L.

0
4.0 EPA
10+

Thousand Oaks, CA Radon Mitigation

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Thousand Oaks, CA Radon Levels

User-submitted radon test readings from homes in the Thousand Oaks area.

Radon LevelCityHome AgeFoundation
5 pCi/L Thousand Oaks, CA 51-99 Years No Basement/All Slab

Have a radon test result for Thousand Oaks? Submit your reading to help other homeowners.

Radon FAQ for Thousand Oaks, CA

What is the average radon level in Thousand Oaks, CA?
Based on 1 user-submitted test, the average radon level in Thousand Oaks is 5.00 pCi/L. This exceeds the EPA's recommended action level of 4.0 pCi/L, and radon testing is recommended for all homes in the area.
What EPA Radon Zone is Thousand Oaks in?
Thousand Oaks and the 91360 zip code are in Ventura County, which has an EPA assigned Radon Zone of 1. A zone of 1 predicts an average indoor radon screening level greater than 4 pCi/L.
How much does radon mitigation cost in Thousand Oaks?
Radon mitigation in Thousand Oaks 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 Thousand Oaks?
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