Locations and reports
Radon Levels in San Bernardino County, California
What this means for you
- Your area: EPA rates San Bernardino County Zone 2, the middle of its three radon zones. That is a prediction for the whole county, and homes with elevated levels occur in all three zones.
- Local tests: Of 178 radon tests reported to CDC for San Bernardino County (2008 to 2017), 4.5% were at or above 4 pCi/L, EPA's action level.
- Your home: The only way to know your home’s level is to test it.
pCi/L (picocuries per liter) is the unit radon is measured in. EPA recommends fixing a home at 4 pCi/L or above, its action level.
Over the 2008 to 2017 laboratory totals, 4.5% of the radon tests reported to CDC for San Bernardino County, California came back at or above the EPA action level of 4 pCi/L, and the median result was 0.7 pCi/L. EPA's Map of Radon Zones places the county in Zone 2, moderate predicted potential. Radon levels vary from home to home, so only a test measures the level in yours.
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
EPA predicts an average indoor of 2 to 4 pCi/L (75 to 150 Bq/m³) across the county as a whole.
This is a county-level geologic prediction. It is not a measurement of any address, and houses with elevated radon are found in all three zones.
USGS geologic potential: High across 84% of the county's land area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for San Bernardino County, 2008 to 2017, laboratory
- Tests reported
- 178
- At or above 4 pCi/L
- 4.5%
- Median result
- 0.7 pCi/L
Of 178 pre-mitigation tests reported to CDC, not homes in this area. CDC publishes the share in each band, not a count per band, so the per-band counts in the table are calculated by Radon411 and rounded to add up to the published total.
| Result band | Tests Calculated by Radon411 | Share Measured |
|---|---|---|
| Under 2 pCi/L | 155 | 87.1% |
| 2 to 4 pCi/L | 15 | 8.4% |
| 4 pCi/L and above | 8 | 4.5% |
Distribution of tested buildings, not this house. People testing before a sale, or because they suspect a problem, are over-represented in any reported testing data.
Measured: CDC tracking data. Figure above: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).
San Bernardino County, In figures
San Bernardino County in figures
What the published data says about San Bernardino County, in words. A zone and a share of tests describe an area, never the level in any one home.
Predicted
PredictedEPA places San Bernardino County in Zone 2, moderate predicted potential, as it does 28 other counties of California's 58.
Of the 8 bordering counties, EPA places Inyo County, Kern County, La Paz County, Los Angeles County, Mohave County and Riverside County in Zone 2 and Clark County and Orange County in Zone 3.
Reported tests
MeasuredCDC publishes no annual figure for San Bernardino County; its figure is a laboratory total for 2008 to 2017: 4.5% of 178 reported tests were at or above 4 pCi/L.
Local record
California's radon program is the California Indoor Radon Program, run by California Department of Public Health; its contacts are under Local resources.
The county's largest incorporated places are San Bernardino, Fontana and Ontario; the figures here cover them as part of the county.
San Bernardino County, State data
California's own radon test data
MeasuredWhat California's own agencies publish about radon tests in San Bernardino County, with their period. These are not CDC's figures and are never added to them.
What the Nevada Radon Education Program reports for the ZIP codes in San Bernardino County
The Nevada Radon Education Program publishes its figures by ZIP code, not by county. These are the ZIP code that lie wholly or partly in San Bernardino County, each with the state's own figures for it. Period: 1989-2015.
| ZIP code | What the state reports |
|---|---|
| 89019 | average 2.2 pCi/L |
- NBMG says the results are based on independently tested homes, not scientific sampling.
- The service publishes an average for each ZIP code but no count of tests.
- Site specific testing is the only way to determine local radon concentrations.
- A ZIP code that crosses the county line is listed whole; its figures cover all of it.
Measured: Nevada Radon Education Program data, 1989-2015.
San Bernardino County, Comparison
How San Bernardino County compares
MeasuredSan Bernardino County's own published CDC figures beside those of the counties that border it, for the same period.
Share of reported tests at or above 4 pCi/L
Measured2008 to 2017, laboratory, highest first. Each county’s own published CDC figure.
- Inyo CountyCA14 tests50.0%
- Kern CountyCA121 tests11.6%
- Los Angeles CountyCA2,363 tests9.5%
- Clark CountyNV2,598 tests8.1%
- San Bernardino CountyThis page178 tests4.5%
- Mohave CountyAZ49 tests4.1%
- Orange CountyCA431 tests3.9%
- Riverside CountyCA226 tests1.3%
Median reported result
Measured2008 to 2017, laboratory, highest first. Each county’s own published CDC figure.
- Inyo CountyCA14 tests4.0 pCi/L
- Kern CountyCA121 tests1.8 pCi/L
- Clark CountyNV2,598 tests0.9 pCi/L
- Los Angeles CountyCA2,363 tests0.7 pCi/L
- Orange CountyCA431 tests0.7 pCi/L
- San Bernardino CountyThis page178 tests0.7 pCi/L
- Riverside CountyCA226 tests0.6 pCi/L
- Mohave CountyAZ49 tests0.2 pCi/L
Each figure is that county’s own published CDC figure for 2008 to 2017, laboratory, counting radon tests reported to CDC, not homes. San Bernardino County is this page. Nothing is averaged or combined across counties. The test count beside each county is CDC’s published number of pre-mitigation tests behind its figures. Figures from few tests can swing widely from year to year. No published CDC figure for 2008 to 2017, laboratory: La Paz County, AZ. Every California county’s own figure is in the California county table.
CDC publishes this figure only for counties here, so there is no state or national number to compare San Bernardino County, California with.
San Bernardino County, Bordering counties
Counties bordering San Bernardino County
Calculated by Radon4118 counties share a boundary with San Bernardino County, computed from Census county geometry. Radon potential follows geology rather than county lines, so a bordering county’s report can be worth reading alongside this one.
- Riverside CountyCAZone 2: Moderate predicted potential
- Clark CountyNVZone 3: Lower predicted potential
- Los Angeles CountyCAZone 2: Moderate predicted potential
- Orange CountyCAZone 3: Lower predicted potential
- Mohave CountyAZZone 2: Moderate predicted potential
- Inyo CountyCAZone 2: Moderate predicted potential
- La Paz CountyAZZone 2: Moderate predicted potential
- Kern CountyCAZone 2: Moderate predicted potential
San Bernardino County, Local resources
Local resources in California
Who to ask in California: the state's radon program, test kits and professionals.
California Indoor Radon Program
California Department of Public Health
California’s radon program answers questions about testing, mitigation and the rules where you live.
- Phone
- 1-800-745-7236
- Radonprogram@cdph.ca.gov
- Licensing of radon professionals
The Radon Program certifies all radon service providers operating in California.
Test kits
The program says: Discounted test kits can be purchased through our partner laboratory, Alpha Energy, for $14.95.
Radon professionals
3 professionals are listed in California.
Professionals in CaliforniaSan Bernardino County, Cities and towns
Cities and towns in San Bernardino County
The radon figures on this page are for San Bernardino County as a whole. They do not differ by city or town.
- San Bernardino
- Fontana
- Ontario
- Rancho Cucamonga
- Victorville
- Rialto
- Hesperia
- Chino
- Upland
- Chino Hills
- Apple Valley
- Redlands
- Highland
- Yucaipa
- Colton
- Adelanto
- Montclair
- Twentynine Palms
- Loma Linda
- Barstow
- Yucca Valley
- Grand Terrace
- Big Bear Lake
- Needles
24 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files.
San Bernardino County, Questions
Questions about radon in San Bernardino County
Common questions8 questions, answered from the figures above
Are radon levels high in San Bernardino County?
In 2017, 4.5% of the radon tests reported to CDC for San Bernardino County, California were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.7 pCi/L. That is a share of reported tests, not of homes. EPA places San Bernardino County in Zone 2, moderate predicted potential, a predicted average indoor screening level 2 to 4 pCi/L. Homes with elevated levels occur in all three zones, so the figures describe the area, not your house. Testing is the only way to know the radon level in a specific building.
How do I get a radon test in San Bernardino County?
EPA says you can test your home yourself or hire a qualified radon test company, and that either approach takes only a small amount of time and effort. No certified tester listed on Radon411 names San Bernardino County as a service area yet. The California radon program is the place to ask about certified testers and any test kit offer it runs.
How to test a homeTest kits comparedFree and low-cost kits by stateCalifornia radon program
Who does radon mitigation in San Bernardino County?
No listed mitigator names San Bernardino County as a service area yet; the California directory lists 3 companies. EPA recommends having a qualified contractor fix a home with a radon problem, because lowering high radon levels takes technical knowledge and special skills, and some states require the work to be done by a licensed or certified professional. Your state radon program is the place to check whether California requires one.
How radon mitigation worksWhat mitigation costsMitigators in California
What EPA radon zone is San Bernardino County in?
EPA places San Bernardino County, California in Zone 2, which EPA describes as moderate predicted potential for the area. A zone is a prediction for the whole county and never determines whether a particular home should be tested. EPA recommends testing every home regardless of zone.
Should I test my home in San Bernardino County?
Yes. Testing is the only way to know the radon level in a specific building. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. How to test a home.
When is the best time of year to test?
EPA says short-term tests stay in the home from 2 to 90 days and that all radon tests should run a minimum of 48 hours; long-term tests stay more than 90 days. EPA's guides do not name a best season: they say radon levels tend to vary from day to day and season to season, so a long-term test is more likely than a short-term test to tell you the year-round average.
What does it cost to test?
EPA's Citizen's Guide calls testing easy and inexpensive, and EPA's Home Buyer's and Seller's Guide says passive short-term and long-term devices are generally inexpensive, while active devices may cost more. No national average price is published for this, so Radon411 does not give one. What testing costs.
Which counties border San Bernardino County?
San Bernardino County borders 8 counties, derived from Census county geometry. Radon potential follows geology rather than county lines, so a bordering county's report can be relevant.
What these figures mean if you own, buy, sell or rent
The reported-test figures on this page describe San Bernardino County, California in 2017. They describe tests other people carried out in other buildings, and none of them measures yours.
- How to test a home
If you own your home
Test the lowest lived-in level; a short-term kit screens in days, a long-term kit reflects the year.
- Buying a house: radon guide
If you are buying
Ask for past results and any system's post-mitigation test, and test during the sale.
- Selling a house: radon guide
If you are selling
Testing before you list puts the timing in your hands; disclosure rules differ by state.
- Radon in rental homes
If you rent, or rent out a home
A tenant can test; a fix is the owner's to make, and duties differ by state.
How long a test has to run, under what conditions, and what EPA says a result means: the testing standard, in full.
San Bernardino County, Products
Testing and mitigation products
Whatever the figures for San Bernardino County show, only a test tells you about one home.
Testing
- Short-term test kitsPassive detectors exposed for a few days under closed-building conditions, then analyzed by a lab.
- Long-term test kitsDetectors exposed for more than 90 days, for a closer picture of the annual average.
- Continuous monitorsPowered devices that log radon on a repeating cycle, often used for transaction tests.
- Digital detectorsConsumer devices that display a running radon reading without a lab.
- Water radon testsKits for radon dissolved in well water, analyzed by a lab.
Mitigation
- Mitigation fansThe inline fan that keeps a soil depressurization system running, sized by the installer.
- System indicatorsU-tube manometers and fan alarms that show whether a mitigation system is still working.
- Sealing materialsCrack, joint and sump sealing used alongside a mitigation system, not instead of one.
San Bernardino County / Next steps
What to do next
Learn
Know what radon is
What radon is, how it gets indoors, and why a county zone is not a reading for your home.
Learn about radonTest
Test the building you live in
Short-term or long-term, where the device goes, and closed-house conditions.
How to testFix
Bring a high level down
How a mitigation system works, and the retest that confirms it.
How mitigation worksFind a pro
Hire a certified professional
Measurement and mitigation professionals by state, with their certifications.
Find a professional
Informational. Follow EPA guidance. EPA says all radon tests should be taken for a minimum of 48 hours, with windows and doors closed from 12 hours before a short-term test.