Skip to content
RADON411

Locations and reports

Radon Levels in Adams County, Idaho

EPA puts Adams County in Zone 3, its lowest radon zone, and high results are common there: 51.6% of the 31 radon tests reported to CDC (2008 to 2017, laboratory totals) came back at or above 4 pCi/L. Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

How to test this homeFind a certified tester

  • Share at 4+ pCi/L

    51.6%

    10.1 pts above ID

    Adams
    51.6%
    Idaho
    41.5%

    31 tests, 2008 to 2017

  • Median result

    4.0pCi/L

    Action level reached

    Adams
    4.0 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    31

    36th of 37 by tests

    Adams
    31
    Ada
    3,030

    Reported to CDC before any fix, 2008 to 2017

  • EPA radon zone

    Zone 3

    Lower potential

    1. 1
    2. 2
    3. Zone 3

    1 highest, 3 lowest

    EPA predicts under 2 pCi/L indoors

  • Rank in Idaho

    12 of 37

    Middle half

    Adams
    51.6%
    Bear Lake
    78.1%

    By share, of 37 with 30+ tests

Read a result for Adams County

Starts at Adams County's median, 4.0 pCi/L

4.0pCi/L

EPA’s own thresholds; the figures are the area’s, never this home’s.

EPA’s reading of 4.0 pCi/L

At or above 4 pCi/L

  1. Under 20 to 1.9 pCi/L
  2. 2 to 4consider a fix
  3. 4 and aboveEPA says fix it

This result is at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. Adams County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Adams County, At a glance

Adams County at a glance

Predicted: EPA radon zone

EPA Zone 3: lower predicted potential

is EPA's lowest class, and its forecast for Adams County as a whole is an average indoor of less than 2 pCi/L (less than 75 Bq/m³). A low zone clears no address in it: homes above EPA's turn up in all three zones.

USGS geologic potential: Low across 85% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Adams County, 2008 to 2017, laboratory

Reported results by concentration band, Adams County, 2008 to 2017, laboratory
Under 2 pCi/L: 19%2 to 4 pCi/L: 29%4 pCi/L and above: 52%

Of 31 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Adams County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L619.4%
2 to 4 pCi/L929.0%
4 pCi/L and above1651.6%
What these figures count

These are the 31 tests reported to CDC for Adams County over 2008 to 2017 (laboratory totals), many from homes being sold or already suspected of a problem: they describe the county's reported tests, not this house.

Measured: CDC tracking data. Figure above: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).

How to read these figures

Adams County, Compared

Adams County radon figures, compared

Calculated by Radon411

More than half: 51.6% of the 31 radon tests reported to CDC for Adams County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 12th of 37 Idaho counties with 30 or more tests for the same period. That is 10.1 points above the 41.5% pooled from 44 Idaho counties.

The median result, 4.0 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 112.4 pCi/L. The rest split 19.4% under 2 pCi/L and 29.0% from 2 to 4 (Idaho: 31.5% and 26.9%). The reported tests do not follow EPA's Zone 3 label for Adams County (predicted average under 2 pCi/L): 51.6% of them reached 4 pCi/L, more than a low-potential zone suggests.

No bordering county with a figure for the same period reported a higher share; the closest is Idaho County at 40.0%, the lowest Gem County at 20.2%. Statewide for the same period, Bear Lake County reported the highest share (78.1%) and Payette County the lowest (4.9%).

CDC's ten-year totals for Adams County went from 35 tests (2005 to 2014) to 31 (2008 to 2017), the share going from 42.9% to 51.6%.

Nationally, every county with a figure for the same period pools to 35.7%; Adams County sits 15.9 points above it. CDC also counts 6 tests taken after mitigation in Adams County for the same period: tests in homes where a fix was already in.

Adams County against Idaho, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Adams County
Adams County3151.6%4.0 pCi/LThis county
Idaho, pooled44 counties, pooled12,96141.5%Not pooled−10.1 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−15.9 points
Bear Lake Countyhighest in the state3278.1%7.8 pCi/L+26.5 points
Payette Countylowest in the state614.9%1.5 pCi/L−46.7 points
Idaho County, IDborders it9040.0%2.9 pCi/L−11.6 points
Baker County, ORborders it4037.5%2.4 pCi/L−14.1 points
Valley County, IDborders it12827.3%2.3 pCi/L−24.3 points
Wallowa County, ORborders it1526.7%1.1 pCi/L−24.9 points
Washington County, IDborders it6720.9%2.1 pCi/L−30.7 points
Gem County, IDborders it9920.2%1.9 pCi/L−31.4 points
Where Adams County's reported results fell, 2008 to 2017, laboratory, beside Idaho and the United States
ResultAdams County testsAdams County shareIdaho shareU.S. shareAgainst Idaho
Under 2 pCi/L619.4%31.5%39.6%−12.1 points
2 to 4 pCi/L929.0%26.9%24.7%+2.1 points
4 pCi/L and above1651.6%41.5%35.7%+10.1 points
Adams County ranked among the 37 Idaho counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Kootenai County7 of 372,95561.0%6.0 pCi/L
Cassia County8 of 3712159.5%5.4 pCi/L
Blaine County9 of 3735257.7%5.3 pCi/L
Teton County10 of 3747353.3%4.4 pCi/L
Bingham County11 of 3744652.0%4.2 pCi/L
Adams County12 of 373151.6%4.0 pCi/L
Fremont County13 of 3710149.5%3.9 pCi/L
Elmore County14 of 3715848.1%3.8 pCi/L
Caribou County15 of 375743.9%3.4 pCi/L
Bannock County16 of 3773241.9%3.2 pCi/L
Bonneville County17 of 371,11740.1%3.4 pCi/L
Adams County ten-year laboratory totals, against Idaho's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestIdaho, pooledChange from the row before
2008 to 20173151.6%4.0 pCi/L112.4 pCi/L41.5%+8.4 points
2007 to 20163743.2%3.4 pCi/L112.4 pCi/L40.8%−1.2 points
2006 to 20153644.4%3.6 pCi/L112.4 pCi/L41.3%+1.5 points
2005 to 20143542.9%3.4 pCi/L112.4 pCi/L41.1%First on file

Pooled shares: Radon411's sum of CDC's county counts for one period.

Adams County, Geology

The ground under Adams County

Predicted

Most of the ground under Adams County is one class on USGS's geologic map: 84.7% of its land is low radon potential, with 15.1% high and 0.3% moderate. The map puts 84.7% of Adams County in the area it calls Seven Devils and Tri-State Uplands and 15.1% in Northern Rocky Mountain Province. USGS gives the first a radon index of 8, in the low band (5 to 8), and the second 12, in the high band (12 to 17).

USGS's geologic areas under Adams County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Seven Devils and Tri-State UplandsColumbia River basalt flows.Low884.7%
Northern Rocky Mountain ProvinceDiorite and granite of the Idaho batholith.High1215.1%

Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.

Adams County beside the ground around it

Idaho as a whole has more high-potential ground than Adams County: 50.7% of its land, against 15.1% here. Of the 6 counties that border it, 3 have more high-potential ground, Valley County the most at 100%.

Share of land by USGS radon potential: Adams County, the 6 counties bordering it and Idaho
AreaEPA zoneLow potentialModerate potentialHigh potential
Adams CountyZone 384.7%0.3%15.1%
Washington CountyZone 388.1%11.9%None
Valley CountyZone 1NoneNone100%
Gem CountyZone 349.0%31.8%19.3%
Wallowa County, ORZone 3None100%None
Baker County, ORZone 2None100%None
Idaho CountyZone 120.7%0.1%79.3%
Idaho44 counties, pooled by land areaVaries8.0%41.3%50.7%

The map rates the ground, not the air in any home.

Local help

Adams County, Local resources

Radon testing and mitigation in Adams County

What Idaho's program says
Phone
800-445-8647
Email
radon@dhw.idaho.gov

What it means

Adams County, Questions

Questions about radon in Adams County

Are radon levels high in Adams County?

Over the 2008 to 2017 laboratory totals, 51.6% of the radon tests reported to CDC for Adams County, Idaho were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.0 pCi/L. Of 37 Idaho counties with 30 or more tests for the same period, 11 reported a higher share; pooled, the state comes to 41.5%.

Which counties border Adams County?

Adams County borders 6 counties: Washington County, ID, Valley County, ID, Gem County, ID, Wallowa County, OR, Baker County, OR and Idaho County, ID.

Products

Adams County, Products

Testing a home in Adams County

In Adams County, 51.6% of 31 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 41.5% pooled across Idaho. Zone 3 is the lowest label, yet homes at or above 4 pCi/L occur in every zone: a short-term kit (2 to 90 days) is the quick first check in Adams County.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Adams County homes, compared

Explore

Adams County, Bordering counties

Counties bordering Adams County

Calculated by Radon411

Adams County, Cities and towns

Cities and towns in Adams County

Adams County is growing: the Census Bureau puts it at 5,013 residents on July 1, 2025, up 13.3% from 4,423 in 2020. Spread over its land, that is 3.7 people to the square mile. No town dominates: Council, the largest, has 985 residents, 19.6% of the total. Together its 2 incorporated places hold 33.3% of those residents; the other 66.7% live outside any of them. CDC's 31 reported tests for 2008 to 2017 work out to 6.2 per 1,000 residents (2025 estimate), close to Idaho's 6.4.

From Council to New Meadows, CDC publishes no figure by town: each reads Adams County's.

The cities and towns in Adams County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Council985+12.2%19.6%
New Meadows684+31.8%13.6%

2 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025).

Adams County, Homes

Homes in Adams County

Adams County is a place of houses on their own lots: 91% of its 2,666 homes are detached single-family houses, against 74% across Idaho. Half of its homes were built before 1984, close to Idaho's 1990: 20% date from before 1960 and 25% from 2000 or later. Owners live in 83% of the occupied homes (Idaho: 72%), so for most households a test and a fix are their own to order.

Homes in Adams County, Idaho, 2019 to 2023
HomesAdams CountyIdaho
Housing units2,666776,683
Detached houses91%74%
In buildings of 5 or more1%9%
Mobile homes5%7%
Built before 196020%18%
Built since 200025%35%
Middle year built19841990
Owner-occupied83%72%

Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.