Castro Valley, CA Radon Mitigation and Testing

Q: What is the average radon level in Castro Valley, CA?

Based on 1 user-submitted tests, the average radon level is 4.00 pCi/L.

Q: What EPA Radon Zone is Castro Valley in?

Castro Valley is in Alameda County, EPA Zone 2.

Q: How much does radon mitigation cost in Castro Valley?

Radon mitigation typically costs between $800 and $2,000. Most standard systems fall in the $1,000-$1,500 range.

Avg: 4.00 pCi/L

Alameda County

EPA Zone 2

1 user test

Castro Valley is located in Alameda County, California. With 1 user-submitted readings averaging 4.00 pCi/L, the area exceeds the EPA's 4.0 pCi/L action threshold, and testing is strongly recommended for homeowners in the 94546 zip code.

4.00

pCi/L average

Above EPA Action Level

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

4.0 EPA

10+

Castro Valley, CA Radon Mitigation

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

Castro Valley, CA Radon Testing

Finding qualified radon testing professionals is the first step toward protecting your home.

Castro Valley, California Radon Levels

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

Radon Level	City	Home Age	Foundation	Submitted
4 pCi/L	Castro Valley, CA	21-50 Years	No Basement/All Crawl Space	Jul 2018

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

Castro Valley Radon Facts

Key details about the radon risk profile for Castro Valley and the 94546 zip code area.

EPA Radon Zone

Zone 2 — Moderate Risk

County

Alameda County, CA

Zip Code

94546

Predicted Screening Level

2–4 pCi/L (Zone 2)

Avg. User Submitted Level

4.00 pCi/L

User Tests Submitted

Castro Valley and the 94546 zip code are located in Alameda County, which has an EPA assigned Radon Zone of 2. A radon zone of 2 predicts an average indoor radon screening level between 2 and 4 pCi/L. The EPA recommends testing every home regardless of zone classification.

Radon FAQ for Castro Valley, CA

What is the average radon level in Castro Valley, CA?

Based on 1 user-submitted test, the average radon level in Castro Valley is 4.00 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 Castro Valley in?

Castro Valley and the 94546 zip code are in Alameda 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 Castro Valley?

Radon mitigation in Castro 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 Castro 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 with the most user-submitted radon test data in the state.

City	Avg User Radon Level	Submissions
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
Woodland Hills	7.67 pCi/L	3
South Lake Tahoe	6.33 pCi/L	3
Palos Verdes Peninsula	6.00 pCi/L	3
Bishop	5.67 pCi/L	3
Sacramento	4.33 pCi/L	3
Oakland	3.33 pCi/L	3
Fresno	10.00 pCi/L	2
Davis	8.00 pCi/L	2
Palo Alto	6.50 pCi/L	2
Studio City	6.50 pCi/L	2
Menlo Park	5.00 pCi/L	2
Truckee	5.00 pCi/L	2
Walnut Creek	4.00 pCi/L	2
San Diego	3.50 pCi/L	2
San Francisco	3.50 pCi/L	2
Belmont	20.00 pCi/L	1