Locations and reports
Radon Levels in Ada County, Idaho
What this means for you
- Your area: EPA rates Ada 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 3,030 radon tests reported to CDC for Ada County (2008 to 2017), 25.2% 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, 25.2% of the radon tests reported to CDC for Ada County, Idaho came back at or above the EPA action level of 4 pCi/L, and the median result was 2.4 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: Moderate across 89% of the county's land area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Ada County, 2008 to 2017, laboratory
- Tests reported
- 3,030
- At or above 4 pCi/L
- 25.2%
- Median result
- 2.4 pCi/L
Of 3,030 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 | 1,194 | 39.4% |
| 2 to 4 pCi/L | 1,073 | 35.4% |
| 4 pCi/L and above | 763 | 25.2% |
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).
Ada County, In figures
Ada County in figures
What the published data says about Ada County, in words. A zone and a share of tests describe an area, never the level in any one home.
Predicted
PredictedEPA places Ada County in Zone 2, moderate predicted potential, as it does 19 other counties of Idaho's 44.
Of the 5 bordering counties, EPA places Boise County and Elmore County in Zone 1, Canyon County and Owyhee County in Zone 2 and Gem County in Zone 3.
Reported tests
MeasuredCDC publishes no annual figure for Ada County; its figure is a laboratory total for 2008 to 2017: 25.2% of 3,030 reported tests were at or above 4 pCi/L.
Local record
Idaho's radon program is the DHW Environmental Health Program, run by Idaho Department of Health and Welfare; its contacts are under Local resources.
The county's largest incorporated places are Boise City, Meridian and Eagle; the figures here cover them as part of the county.
Ada County, Comparison
How Ada County compares
MeasuredAda 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.
- Elmore CountyID158 tests48.1%
- Ada CountyThis page3,030 tests25.2%
- Owyhee CountyID30 tests23.3%
- Boise CountyID58 tests22.4%
- Gem CountyID99 tests20.2%
- Canyon CountyID563 tests10.7%
Median reported result
Measured2008 to 2017, laboratory, highest first. Each county’s own published CDC figure.
- Elmore CountyID158 tests3.8 pCi/L
- Ada CountyThis page3,030 tests2.4 pCi/L
- Owyhee CountyID30 tests2.1 pCi/L
- Boise CountyID58 tests2.0 pCi/L
- Gem CountyID99 tests1.9 pCi/L
- Canyon CountyID563 tests1.6 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. Ada 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. Every Idaho county’s own figure is in the Idaho county table.
CDC publishes this figure only for counties here, so there is no state or national number to compare Ada County, Idaho with.
Ada County, Bordering counties
Counties bordering Ada County
Calculated by Radon4115 counties share a boundary with Ada 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.
Ada County, 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 directoryAda County, Cities and towns
Cities and towns in Ada County
The radon figures on this page are for Ada County as a whole. They do not differ by city or town.
- Boise City
- Meridian
- Eagle
- Kuna
- Star (part)
- Garden City
6 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. “(part)” marks a place that extends into another county.
Ada County, Questions
Questions about radon in Ada County
Common questions8 questions, answered from the figures above
Are radon levels high in Ada County?
In 2017, 25.2% of the radon tests reported to CDC for Ada County, Idaho were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.4 pCi/L. That is a share of reported tests, not of homes. EPA places Ada 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 Ada 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 Ada County as a service area yet. The Idaho 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 stateIdaho radon program
Who does radon mitigation in Ada County?
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. Your state radon program is the place to check whether Idaho requires one.
How radon mitigation worksWhat mitigation costsIdaho radon program
What EPA radon zone is Ada County in?
EPA places Ada County, Idaho 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 Ada 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 Ada County?
Ada County borders 5 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 Ada County, Idaho 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.
Ada County, Products
Testing and mitigation products
Whatever the figures for Ada 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.
Ada 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.