Altadena, CA Radon Mitigation and Testing

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

Based on 1 user-submitted tests, the average radon level is 6.00 pCi/L.

Q: What EPA Radon Zone is Altadena in?

Altadena is in Los Angeles County, EPA Zone 2.

Q: How much does radon mitigation cost in Altadena?

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

Avg: 6.00 pCi/L

Los Angeles County

EPA Zone 2

1 user test

Nestled against the San Gabriel Mountains in Los Angeles County, Altadena's unique foothill location has produced a 6.0 pCi/L reading that exceeds the EPA action level. The community's granite and alluvial fan geology, combined with its mix of historic and mid-century homes in ZIP code 91001, creates localized radon conditions that can vary significantly from California's typically lower statewide averages.

6.00

pCi/L average

Above EPA Action Level

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

4.0 EPA

10+

Altadena, CA Radon Mitigation

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

Altadena, CA Radon Testing

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

Altadena, California Radon Levels

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

Radon Level	City	Home Age	Foundation	Submitted
6 pCi/L	Altadena, CA	51-99 Years	No Basement/All Crawl Space	Mar 2021

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

Altadena Radon Facts

Key details about the radon risk profile for Altadena and the 91001 zip code area.

EPA Radon Zone

Zone 2 — Moderate Risk

County

Los Angeles County, CA

Zip Code

91001

Predicted Screening Level

2–4 pCi/L (Zone 2)

Avg. User Submitted Level

6.00 pCi/L

User Tests Submitted

Altadena and the 91001 zip code are located in Los Angeles 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 Altadena, CA

What is the average radon level in Altadena, CA?

Based on 1 user-submitted test, the average radon level in Altadena is 6.00 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 Altadena in?

Altadena and the 91001 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 Altadena?

Radon mitigation in Altadena 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 Altadena?

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