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California Radon Information

California Radon Program:

Radon Website: Website
Radon Contact: Radon Program Manager
Active Radon Program: Yes
Require License for Radon Professionals: Yes

California Radon Levels

California has a user submitted radon level of 5.7. This is based on data submitted from visitors on our site. Learn more here.

EPA Radon Levels

California has 58 counties and 2 (3%) have been assigned Zone 1 counties by the EPA. Zone 1 counties have the highest potential to have homes test higher than 4 pCi/L. California's state radon zone average is 2.43, which is the average of all county zone ratings the EPA has assigned the state, ranking it 40 among all states.

The radon levels in the state of California are about average. However there is an increased risk for all homeowners, which is why we recommend testing exposure levels at least twice a year.


California Radon Mitigation and Testing

Need your home tested for radon? Already know you have high levels and need a radon reduction system installed? Finding qualified Radon professionals can be difficult, but we've put together a list of California contractors to help you save time.

California Radon Mitigation

We have compiled a list of qualified radon mitigation contractors.
Find Radon Mitigation Contractors here

California Radon Testing

Need your home or office tested for Radon? We have compiled a list of qualified radon testing contractors.
Find Radon Testing Contractors here


California Radon Contractor License Information

Does California require contractors to be licensed? Yes.

What are the licensing requirements? Interested mitigators must first have one of the following contractor’s licenses as issued by the California Department of Consumer Affairs:

  1. B, C20, C36, D64.
  2. They must complete an approved radon mitigation training program, and obtain a certification by one of the two radon certifying boards (NRPP, NRSB).
  3. They must submit a "Radon Certification Verification Form" along with a copy of their certificate to the Indoor Radon Program.

Those interested in a radon testing certification must follow through with the last two steps - no prior licenses are required.

Those looking for a radon certification can also take qualified third party courses that are offered through the NRPP or AASRT.


California Radon Real Estate Requirements

Does the state of California require radon testing for all real estate transactions? No

However both the state of California and the EPA recommend that a home or residence should be tested before a real estate transaction is carried out. Even though California does not require radon testing, we certainly recommend you have a test performed before you purchase a home. If you decide to perform a test after and find elevated levels, there is no reason to panic. California radon mitigation is not expensive compared to the dangers and a system can be implemented in a relatively short period of time.


California Radon Map

Map of California Radon Levels

Zone 1 (1): Potential for radon levels above 4 pCi/L according to EPA
Zone 2 (2): Potential for radon levels between 2 pCi/L and 4 pCi/L according to the EPA
Zone 3 (3): Lowest EPA level with expected radon levels at or below 2 pCi/L
Disclaimer: It is strongly recommended that all households, schools and office spaces test radon levels individually. The EPA Radon Zone data is not an indicator of individual test results, but a guideline for strategic planning. Toxic radon levels can be found in all counties, regardless of their zone rating. While we make efforts to keep this information up to date, it is derived from third­party sources which may not be accurate or reflect the most current statistics.


About California

California is the most populous state with 38 million people, or every one out of eight Americans. It is also the third largest state by surface area in the country, right behind Alaska and Texas.

Residents of the Alpine, Mono and Inyo counties are being offered free radon testing kits from the California Department of Public Health in association with the US EPA, CDPH and California Geological Survey. If you live in one of the aforementioned counties it is recommended that you take the opportunity to acquire a testing kit. The free test kits do include mailing supplies and an analysis of the test results.


Browse The National Radon Directory by City

Acampo
Acton
Adelanto
Adin
Agoura Hills
Aguanga
Ahwahnee
Alameda
Alamo
Albany
Albion
Alderpoint
Alhambra
Aliso Viejo
Alleghany
Alpine
Altadena
Alturas
American Canyon
Anaheim
Anderson
Angels Camp
Angelus Oaks
Angwin
Annapolis
Antelope
Antioch
Anza
Apple Valley
Applegate
Aptos
Arbuckle
Arcadia
Arcata
Armona
Arnold
Aromas
Arroyo Grande
Artesia
Arvin
Atascadero
Atherton
Atwater
Auberry
Auburn
Avenal
Azusa
Badger
Baker
Bakersfield
Baldwin Park
Ballico
Bangor
Banning
Barstow
Bass Lake
Bayside
Beale Afb
Beaumont
Beckwourth
Bell Gardens
Bella Vista
Bellflower
Belmont
Belvedere Tiburon
Ben Lomond
Benicia
Benton
Berkeley
Berry Creek
Beverly Hills
Big Bar
Big Bear City
Big Bear Lake
Big Pine
Big Sur
Biggs
Birds Landing
Bishop
Blairsden-graeagle
Blocksburg
Bloomington
Blue Lake
Blythe
Bodega
Bodega Bay
Bodfish
Bolinas
Bonita
Bonsall
Boonville
Boron
Borrego Springs
Boulder Creek
Boulevard
Bradley
Branscomb
Brawley
Brea
Brentwood
Bridgeport
Bridgeville
Brisbane
Brooks
Browns Valley
Brownsville
Buellton
Buena Park
Burbank
Burlingame
Burney
Burnt Ranch
Butte City
Buttonwillow
Byron
Cabazon
Calabasas
Calexico
Caliente
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Camino
Camp Pendleton
Campbell
Campo
Camptonville
Canby
Canoga Park
Cantua Creek
Canyon Country
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Capay
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Capitola
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Carlotta
Carlsbad
Carmel
Carmel Valley
Carmichael
Carpinteria
Carson
Caruthers
Caspar
Cassel
Castaic
Castella
Castro Valley
Castroville
Cathedral City
Catheys Valley
Cayucos
Cazadero
Cedarville
Ceres
Cerritos
Challenge
Chatsworth
Chester
Chico
Chilcoot
Chino
Chino Hills
Chowchilla
Chualar
Chula Vista
Cima
Citrus Heights
Claremont
Clarksburg
Clayton
Clearlake
Clearlake Oaks
Clipper Mills
Cloverdale
Clovis
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Colton
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Comptche
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Concord
Cool
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Corcoran
Corning
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Coronado
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Cotati
Cottonwood
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Cutler
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Descanso
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Diamond Bar
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Dinuba
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Dixon
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Downey
Doyle
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