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Radon Levels in Garfield County, Washington

EPA puts Garfield County in Zone 2, its middle radon zone, and only 1 radon test from it is on file with CDC (2019). 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

  • Highest bordering

    22.4%

    Whitman County

    Whitman
    22.4%

    1 of 4 neighbours have 30+ tests, 2008 to 2017

  • Nearest county

    22.4%

    Whitman County, 32 miles

    Whitman
    22.4%
    Washington
    25.5%

    Share at 4+ pCi/L, 58 tests, 2008 to 2017

  • Ground above low

    100.0%

    47.3 pts above Washington

    Garfield
    100.0%
    Washington
    52.7%

    Share of land USGS rates moderate or high potential

  • Tests reported

    2

    Too few for a share

    Garfield
    2
    Needed
    30

    2008 to 2017, laboratory

  • EPA radon zone

    Zone 2

    Moderate potential

    1. 1
    2. Zone 2
    3. 3

    1 highest, 3 lowest

    EPA predicts 2 to 4 pCi/L indoors

Read a result for Garfield County

Starts at EPA's action level

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.

Interpret this readingWhat a fix costs

The data

Garfield County, At a glance

Garfield County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Garfield County is a county: EPA's forecast for it as a whole is an average indoor of 2 to 4 pCi/L (75 to 150 Bq/m³). It describes no single address, and homes above EPA's are found in every zone, this one included.

USGS geologic potential: Moderate across 100% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Garfield County, 2019

CDC holds 1 reported test for Garfield County in 2019, a result of 5.5 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Garfield County beside the counties around it is how this page reads it.

What these figures count

Only 1 test was reported to CDC for Garfield County over 2019, and tests are often run on homes being sold or already suspected of a problem: so few describe neither the county nor this house.

Measured: CDC tracking data. Figure above: 2019. Measured data period: 2005 to 2019 (every CDC figure on file).

How to read these figures

Garfield County, Compared

Garfield County radon figures, compared

Calculated by Radon411

CDC's largest figure for Garfield County rests on 2 tests over the 2008 to 2017 laboratory totals, 1 of them at or above 4 pCi/L, so each test moves its share by 50.0 points and no rank or comparison is drawn from it. Results reached as high as 5.9 pCi/L, with a middle value of 3.8 pCi/L.

Whitman County, the one bordering county with a figure over the 2008 to 2017 laboratory totals, reported 22.4% of its tests at or above 4 pCi/L. Farther out, Walla Walla County (47 miles away) at 16.4%, Spokane County (82 miles away) at 41.4% and Benton County (95 miles away) at 19.5% have figures too. Pooled across 39 Washington counties, 25.5% of reported tests reached that level; across every county in the country with a figure, 35.7%.

Statewide for the same period, Pend Oreille County reported the highest share (63.2%) and Snohomish County the lowest (2.3%). EPA's 1993 map puts Garfield County in Zone 2, its middle label: a predicted county average between 2 and 4 pCi/L. USGS geology rates 100% of the county's land moderate radon potential.

Washington, the United States and the counties around Garfield County, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedian
Washington, pooled39 counties, pooled8,20125.5%Not pooled
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled
Pend Oreille Countyhighest in the state3863.2%4.8 pCi/L
Snohomish Countylowest in the state2652.3%0.5 pCi/L
Columbia County, WAborders it4100.0%6.6 pCi/L
Wallowa County, ORborders it1526.7%1.1 pCi/L
Whitman County, WAborders it5822.4%1.5 pCi/L
Asotin County, WAborders it60.0%1.3 pCi/L
The nearest Washington counties to Garfield County with 30 or more tests, 2008 to 2017, laboratory
CountyDistanceTestsAt or above 4 pCi/LMedian
Whitman County32 mi5822.4%1.5 pCi/L
Walla Walla County47 mi12216.4%1.4 pCi/L
Spokane County82 mi3,12541.4%2.9 pCi/L
Benton County95 mi11319.5%2.0 pCi/L
Stevens County137 mi19636.2%2.3 pCi/L
Pend Oreille County146 mi3863.2%4.8 pCi/L
Yakima County152 mi807.5%0.7 pCi/L
Chelan County176 mi4814.6%1.8 pCi/L
Garfield County ten-year laboratory totals, against Washington's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestWashington, pooledChange from the row before
2008 to 2017250.0%3.8 pCi/L5.9 pCi/L25.5%Level
2007 to 2016250.0%3.8 pCi/L5.9 pCi/L25.5%Level
2006 to 2015250.0%3.8 pCi/L5.9 pCi/L25.9%Level
2005 to 2014250.0%3.8 pCi/L5.9 pCi/L27.2%First on file

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

Garfield County, Geology

The ground under Garfield County

Predicted

USGS's geologic map puts all of Garfield County's mapped land in one class: moderate radon potential. The map puts 73.5% of Garfield County in the area it calls Columbia Basin and 26.4% in Blue Mountains. USGS gives the first a radon index of 10 and the second 9, both in the moderate band (9 to 11).

USGS's geologic areas under Garfield County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Columbia BasinBasaltic rocks low in uranium content. Uranium content of soils is moderately elevated.Moderate1073.5%
Blue MountainsTertiary basalt, andesite, tuffaceous sedimentary rocks, and tuff.Moderate926.4%

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

Garfield County beside the ground around it

Across Washington 13.7% of the land is rated high; none of Garfield County's is. Of the 4 counties that border it, 1 has more high-potential ground, Whitman County the most at 0.9%.

Share of land by USGS radon potential: Garfield County, the 4 counties bordering it and Washington
AreaEPA zoneLow potentialModerate potentialHigh potential
Garfield CountyZone 2None100%None
Columbia CountyZone 2None100%None
Asotin CountyZone 2None100%None
Whitman CountyZone 2None99.1%0.9%
Wallowa County, ORZone 3None100%None
Washington38 counties, pooled by land areaVaries46.4%39.0%13.7%

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

Local help

Garfield County, Local resources

Radon testing and mitigation in Garfield County

What Washington's program says
Phone
360-236-3200
Email
doh.radon@doh.wa.gov

What it means

Garfield County, Questions

Questions about radon in Garfield County

Are radon levels high in Garfield County?

In 2019, 100.0% of the radon tests reported to CDC for Garfield County, Washington were at or above 4 pCi/L, and the median reported pre-mitigation result was 5.5 pCi/L. Whitman County, the one bordering county with a figure over the 2008 to 2017 laboratory totals, reported 22.4% of its tests at or above 4 pCi/L.

Which counties border Garfield County?

Garfield County borders 4 counties: Columbia County, WA, Asotin County, WA, Whitman County, WA and Wallowa County, OR.

Products

Garfield County, Products

Testing a home in Garfield County

No CDC figure names Garfield County; the nearest county with one, Whitman County (32 miles away), reported 22.4% of its tests at or above 4 pCi/L over the 2008 to 2017 laboratory totals, the only reading nearby until a test of this home. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Garfield County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Garfield County homes, compared

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Garfield County, Bordering counties

Counties bordering Garfield County

Calculated by Radon411

Garfield County, Cities and towns

Cities and towns in Garfield County

Garfield County is growing: the Census Bureau puts it at 2,416 residents on July 1, 2025, up 5.2% from 2,296 in 2020. Spread over its land, that is 3.4 people to the square mile. Pomeroy, its one incorporated place, has 1,481 residents, 61.3% of the total. CDC's 2 reported tests for 2008 to 2017 work out to 0.8 per 1,000 residents (2025 estimate), close to Washington's 1.0.

Pomeroy is the one incorporated place here; CDC publishes no figure by town, so it reads Garfield County's.

Pomeroy, Garfield County: residents on July 1, 2025
PlaceResidentsSince 2020Share of residents
Pomeroy1,481+5.6%61.3%

One incorporated place, 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).

Garfield County, Homes

Homes in Garfield County

Of Garfield County's 1,223 homes, 74% are detached houses, against 62% across Washington; 20% are mobile homes. The homes are older than Washington's as a whole: half were built before 1953 (1984 for Washington), and 60% date from before 1960. Owners live in 77% of the occupied homes (Washington: 64%), so for most households a test and a fix are their own to order.

Homes in Garfield County, Washington, 2019 to 2023
HomesGarfield CountyWashington
Housing units1,2233,262,667
Detached houses74%62%
In buildings of 5 or more2%22%
Mobile homes20%6%
Built before 196060%21%
Built since 200010%28%
Middle year built19531984
Owner-occupied77%64%

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