Find Radon Testers in California
Certified radon testing and mitigation professionals across California. Browse 20+ listed providers below.
Radon Risk Level
EPA data for this state
Generally low potential; Sierra Nevada foothills higher.
Browse by City in California
Orange
9 providers
Roseville
8 providers
Oakland
6 providers
San Diego
6 providers
Los Angeles
5 providers
Chula Vista
5 providers
San Jose
5 providers
Irvine
4 providers
Long Beach
3 providers
Thousand Oaks
3 providers
Fresno
3 providers
Moorpark
3 providers
Hayward
2 providers
Tahoe City
2 providers
Huntington Beach
2 providers
San Leandro
2 providers
Anaheim
2 providers
Citrus Heights
2 providers
Garden Grove
2 providers
Santa Monica
2 providers
Santa Barbara
2 providers
Concord
2 providers
Somis
2 providers
Torrance
2 providers
El Dorado Hills
1 provider
Antelope
1 provider
Bonsall
1 provider
Elk Grove
1 provider
Mission Viejo
1 provider
Sacramento
1 provider
San Pedro
1 provider
Redlands
1 provider
Stockton
1 provider
Tustin
1 provider
Chino Hills
1 provider
Altadena
1 provider
Aliso Viejo
1 provider
Danville
1 provider
Paramount
1 provider
Ladera Ranch
1 provider
Pleasant Hill
1 provider
Santa Ana
1 provider
Woodland Hills
1 provider
San Bernardino
1 provider
Sebastopol
1 provider
Apple Valley
1 provider
Chatsworth
1 provider
Berkeley
1 provider
Inglewood
1 provider
Auburn
1 provider
Bonita
1 provider
Clovis
1 provider
Diamond Springs
1 provider
Calimesa
1 provider
El Segundo
1 provider
Gardena
1 provider
Madera
1 provider
Chico
1 provider
Clayton
1 provider
Corona
1 provider
Menifee
1 provider
Lancaster
1 provider
Monterey
1 provider
Rocklin
1 provider
Redondo Beach
1 provider
Seal Beach
1 provider
Watsonville
1 provider
Simi Valley
1 provider
Vista
1 provider
Beverly Hills
1 provider
Chino
1 provider
Davis
1 provider
Escondido
1 provider
Encinitas
1 provider
Encino
1 provider
Grass Valley
1 provider
Lake Arrowhead
1 provider
Lompoc
1 provider
Newhall
1 provider
Markleeville
1 provider
Pasadena
1 provider
Rialto
1 provider
Riverside
1 provider
San Francisco
1 provider
Studio City
1 provider
Signal Hill
1 provider
South Lake Tahoe
1 provider
Valencia
1 provider
Ventura
1 provider
Yorba Linda
1 provider
Radon Providers in California(showing top 20)
Radon Testing in California — FAQ
How often should I test for radon in California?
The EPA recommends testing every two years in California. Always test when moving into a new home, after renovations that affect lower levels, and after installing a mitigation system.
What is the EPA action level for radon?
The EPA recommends taking action to reduce radon if indoor levels reach 4 pCi/L or higher. Even levels between 2–4 pCi/L present risk, and mitigation is recommended where feasible.
Do I need a certified radon tester in California?
For real estate transactions, most states require a certified tester. Look for NRPP or AARST-NRPP certification. California may also have its own state program — check your state radon office for specific requirements.