Locations and reports
Radon Levels in Idaho
What this means for you
- Your area: EPA rates 19 of Idaho's 44 classified counties Zone 1, the highest of its three radon zones. Zones are predictions for whole counties, and homes with elevated levels occur in all three zones.
- Local tests: CDC publishes Idaho's radon test results by county. Open your county below to see its figures.
- 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.
For Idaho, EPA's Map of Radon Zones places 19 of its 44 classified counties in Zone 1, highest predicted potential, a prediction for each county as a whole. Radon levels vary from home to home, so only a test measures the level in yours.
Predicted: EPA radon zone
44 of 44 counties classified
EPA classifies counties, not states. Of the 44 counties in Idaho with a zone, 19 are in Zone 1, 20 in Zone 2 and 5 in Zone 3.
- Zone 1: Highest predicted potentialgreater than 4 pCi/L19 of 44 counties · 43.2%
- Zone 2: Moderate predicted potential2 to 4 pCi/L20 of 44 counties · 45.5%
- Zone 3: Lower predicted potentialless than 2 pCi/L5 of 44 counties · 11.4%
An EPA radon zone describes predicted potential across a whole county. It is not intended to determine whether any individual home should be tested, and homes with elevated levels occur in all three zones. EPA recommends testing every home regardless of zone, and testing is the only way to know the radon level in a specific building.
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.
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
CDC publishes Idaho's radon test figures by county: 44 of its 44 counties have one. Each county's share is in the county list.
Idaho, In figures
Idaho in figures
What the published data says about Idaho, in words. A zone and a share of tests describe an area, never the level in any one home.
Predicted
PredictedEPA places 19 of Idaho's 44 counties in Zone 1, 20 in Zone 2 and 5 in Zone 3.
Zone 1 counties, A to Z, begin with Benewah County, Blaine County and Boise County; the county section below lists all 19.
Compared
Calculated by Radon41143% of Idaho's counties with a zone on file are in Zone 1, a larger share than across all U.S. counties (34%). It is a share of counties, not of land, people or homes.
Reported tests
MeasuredCDC has no statewide testing figure for Idaho on file here.
44 of the 44 counties have a published county figure; the most tests in each one's latest year were reported for Ada County (2,395 in 2017), Kootenai County (2,103 in 2017) and Bonneville County (751 in 2017).
Idaho's radon program is the DHW Environmental Health Program, run by Idaho Department of Health and Welfare; its contacts are under Local resources.
Idaho, Counties
Idaho counties by EPA zone
PredictedAll 44 counties, by the zone EPA predicts for each. Every county has its own report.
Zone 1: highest predicted potential19
- Benewah County31.0% of reported tests at or above 4 pCi/L, 2017
- Blaine County57.7% of reported tests at or above 4 pCi/L, 2017
- Boise County22.4% of reported tests at or above 4 pCi/L, 2017
- Bonner County33.0% of reported tests at or above 4 pCi/L, 2017
- Boundary County20.0% of reported tests at or above 4 pCi/L, 2017
- Butte County75.9% of reported tests at or above 4 pCi/L, 2017
- Camas County27.3% of reported tests at or above 4 pCi/L, 2017
- Clark County75.0% of reported tests at or above 4 pCi/L, 2017
- Clearwater County30.3% of reported tests at or above 4 pCi/L, 2017
- Custer County72.7% of reported tests at or above 4 pCi/L, 2017
- Elmore County48.1% of reported tests at or above 4 pCi/L, 2017
- Fremont County49.5% of reported tests at or above 4 pCi/L, 2017
- Gooding County28.4% of reported tests at or above 4 pCi/L, 2017
- Idaho County40.0% of reported tests at or above 4 pCi/L, 2017
- Kootenai County61.0% of reported tests at or above 4 pCi/L, 2017
- Latah County26.0% of reported tests at or above 4 pCi/L, 2017
- Lemhi County65.2% of reported tests at or above 4 pCi/L, 2017
- Shoshone County63.0% of reported tests at or above 4 pCi/L, 2017
- Valley County27.3% of reported tests at or above 4 pCi/L, 2017
Zone 2: moderate predicted potential20
- Ada County25.2% of reported tests at or above 4 pCi/L, 2017
- Bannock County41.9% of reported tests at or above 4 pCi/L, 2017
- Bear Lake County78.1% of reported tests at or above 4 pCi/L, 2017
- Bingham County52.0% of reported tests at or above 4 pCi/L, 2017
- Bonneville County40.1% of reported tests at or above 4 pCi/L, 2017
- Canyon County10.7% of reported tests at or above 4 pCi/L, 2017
- Caribou County43.9% of reported tests at or above 4 pCi/L, 2017
- Cassia County59.5% of reported tests at or above 4 pCi/L, 2017
- Franklin County34.7% of reported tests at or above 4 pCi/L, 2017
- Jefferson County67.1% of reported tests at or above 4 pCi/L, 2017
- Jerome County16.9% of reported tests at or above 4 pCi/L, 2017
- Lincoln County40.0% of reported tests at or above 4 pCi/L, 2017
- Madison County63.7% of reported tests at or above 4 pCi/L, 2017
- Minidoka County15.3% of reported tests at or above 4 pCi/L, 2017
- Oneida County74.1% of reported tests at or above 4 pCi/L, 2017
- Owyhee County23.3% of reported tests at or above 4 pCi/L, 2017
- Payette County4.9% of reported tests at or above 4 pCi/L, 2017
- Power County26.8% of reported tests at or above 4 pCi/L, 2017
- Teton County53.3% of reported tests at or above 4 pCi/L, 2017
- Twin Falls County24.1% of reported tests at or above 4 pCi/L, 2017
Zone 3: lower predicted potential5
- Adams County51.6% of reported tests at or above 4 pCi/L, 2017
- Gem County20.2% of reported tests at or above 4 pCi/L, 2017
- Lewis County50.0% of reported tests at or above 4 pCi/L, 2017
- Nez Perce County22.1% of reported tests at or above 4 pCi/L, 2017
- Washington County20.9% of reported tests at or above 4 pCi/L, 2017
Idaho, Local resources
Local resources in Idaho
Who to ask in Idaho: the state's radon program, test kits and professionals.
DHW Environmental Health Program
Idaho Department of Health and Welfare
Idaho’s radon program answers questions about testing, mitigation and the rules where you live.
- Phone
- 800-445-8647
- radon@dhw.idaho.gov
Test kits
The program says: Order a free radon test kit.
Radon professionals
No professionals are listed in Idaho yet. The state program can point you to registered testers and mitigators.
See the Idaho directoryIdaho, Questions
Questions about radon in Idaho
Common questions9 questions, answered from the figures above
Is radon a problem in Idaho?
EPA's Map of Radon Zones places 19 of the 44 Idaho counties it classifies in Zone 1, the highest predicted potential, 20 in Zone 2 and 5 in Zone 3. An EPA radon zone describes predicted potential across a whole county. It is not intended to determine whether any individual home should be tested, and homes with elevated levels occur in all three zones. EPA recommends testing every home regardless of zone, and testing is the only way to know the radon level in a specific building.
How do I get a radon test in Idaho?
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. The Idaho radon program is the place to ask about certified testers and any test kit offer it runs.
How to test a homeFree and low-cost kits by stateIdaho radon program
Which Idaho counties are in EPA radon Zone 1?
19 counties are in Zone 1: Benewah County, Blaine County, Boise County, Bonner County, Boundary County, Butte County, Camas County, Clark County, and 11 more in the county table on this page. Zone 1 is EPA's class for highest predicted potential, a predicted average indoor screening level greater than 4 pCi/L. A zone is a prediction for a county, not a measurement of any home.
Radon in Benewah CountyRadon in Blaine CountyRadon in Boise County
Who does radon mitigation in Idaho?
Radon411 has no certified mitigators listed for Idaho yet. 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.
How radon mitigation worksWhat mitigation costsRadon professionals in Idaho
Which Idaho counties have the highest radon?
44 of Idaho's 44 counties have an EPA radon zone published here. Radon411 will not rank counties on data it does not hold, and a zone is a prediction for an area rather than a measurement of any building.
What share of radon tests in Idaho are high?
CDC has published no statewide radon testing statistics for Idaho, so we cannot give a figure. Where CDC does publish one, the percentage describes radon tests reported to CDC, not homes.
Which EPA region is Idaho in?
Idaho is in EPA Region 10: Pacific Northwest.
Do I need to test my home in Idaho?
Yes, wherever you live in the state. 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.
Why does this page show coverage rather than one radon level for Idaho?
A statewide figure averages counties with very different geology and very different numbers of reported tests, so it hides more than it shows. The county report is the level at which the EPA zone, the geologic potential and the reported testing statistics are actually published, which is why the county table above links to every one of them.
What these figures mean if you own, buy, sell or rent
The zone counts on this page describe counties across Idaho. They are predictions for areas, and none of them measures your building.
- 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.
Idaho, Products
Testing and mitigation products
Whatever the figures for Idaho 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.
Idaho / 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.