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Grass Valley, CA Radon Levels

Check local Grass Valley radon levels and find certified testing and mitigation professionals to keep your home safe


Grass Valley, CA Radon Facts

EPA Radon Zone Zone 2 — Moderate Risk 2–4 pCi/L (Zone 2)
County Nevada County, CA
Zip Code 95945
Avg. User Level 11.50 pCi/L
User Tests 2

Perched in the Sierra Nevada foothills of Nevada County, Grass Valley's zip codes 95945 and 95949 have recorded an average radon level of 11.5 pCi/L, significantly exceeding the EPA action level. Built on gold-bearing metamorphic bedrock and granitic soils from historic mining activities, the area's Victorian-era homes and newer mountain residences often feature partial basements or crawl spaces. Given these elevated readings, all residents should test their homes and implement mitigation measures if necessary.

11.50
pCi/L average
Above EPA Action Level

Based on 2 user-submitted radon tests for homes in Grass Valley, CA. The EPA recommends taking action at or above 4.0 pCi/L.

0
4.0 EPA
10+

Grass Valley, CA Radon Mitigation

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Grass Valley, CA Radon Levels

User-submitted radon test readings from homes in the Grass Valley area.

Radon LevelCityHome AgeFoundation
10 pCi/L Grass Valley, CA 0-20 Years Partial Basement
13 pCi/L Grass Valley, CA 0-20 Years No Basement/All Slab

Have a radon test result for Grass Valley? Submit your reading to help other homeowners.

Radon FAQ for Grass Valley, CA

What is the average radon level in Grass Valley, CA?
Based on 2 user-submitted tests, the average radon level in Grass Valley is 11.50 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 Grass Valley in?
Grass Valley and the 95945 zip code are in Nevada 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 Grass Valley?
Radon mitigation in Grass Valley 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 Grass Valley?
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