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Radon Levels in Umatilla County, Oregon

EPA puts Umatilla County in Zone 2, its middle radon zone, and only 18 radon tests from it are on file with CDC (2023). 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

    34.8%

    18.5 pts above OR

    Umatilla
    34.8%
    Oregon
    16.3%

    46 tests, 2021

  • Median result

    2.9pCi/L

    Below action level

    Umatilla
    2.9 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2021

  • Tests reported

    46

    15th of 19 by tests

    Umatilla
    46
    Multnomah
    1,623

    Reported to CDC before any fix, 2021

  • 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

  • Rank in Oregon

    1 of 19

    Top quarter

    Umatilla
    34.8%
    Umatilla
    34.8%

    By share, of 19 with 30+ tests

Read a result for Umatilla County

Starts at Umatilla County's median, 2.9 pCi/L

2.9pCi/L

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

EPA’s reading of 2.9 pCi/L

Between 2 and 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 between 2 and 4 pCi/L. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. Umatilla County's median reported result, 2021.

Interpret this readingWhat a fix costs

The data

Umatilla County, At a glance

Umatilla County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Umatilla 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 Umatilla County, 2023

Share of reported tests at or above 4 pCi/L, by year, Umatilla County
Share of reported tests at or above 4 pCi/L, by year, Umatilla County
YearShare of reported tests at or above 4 pCi/L
201425.0%
201510.0%
201620.0%
201714.3%
201812.5%
201942.9%
202020.0%
202134.8%
20220.0%
202311.1%

2023: 11.1%. Across these years the share ran from 0.0% to 42.9%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

Only 18 tests were reported to CDC for Umatilla County over 2023, 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: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).

How to read these figures

Umatilla County, Compared

Umatilla County radon figures, compared

Calculated by Radon411

In Umatilla County, about 3 in 10 reported tests in 2021 (16 of 46) were at or above EPA's action level. Against the national pool of 24.4%, the gap is 10.4 points higher. Across 33 Oregon counties pooled together, 16.3% of tests reached that level, so Umatilla County runs 18.5 points above its state.

The newest figure, in 2023, counts only 18 tests (11.1% at or above 4 pCi/L), too few to compare, so this reading uses the 46-test figure.

Union County, the one bordering county with a figure for the same period, reported 34.6%. By share, Umatilla County is 1st of 19 Oregon counties with 30 or more tests for the same period.

Half the tests came in under 2.9 pCi/L and half over it; the single highest reached 34.8 pCi/L. Below the action level, 10 tests (21.7%) came in under 2 pCi/L, against 62.9% statewide, and 20 tests (43.5%) fell between 2 and 4, against 20.8% statewide.

Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 34.8% share point the same way here. USGS geology rates 100% of the county's land moderate radon potential.

The busiest year on file was 2021, with 46 tests reported; the quietest, 2022, had 6.

Umatilla County against Oregon, the United States and nearby counties, 2021
AreaTestsAt or above 4 pCi/LMedianDifference from Umatilla County
Umatilla County4634.8%2.9 pCi/LThis county
Oregon, pooled33 counties, pooled4,46316.3%Not pooled−18.5 points
United States, pooled807 counties, pooled344,60424.4%Not pooled−10.4 points
Clatsop Countyhighest in the state3330.3%1.9 pCi/L−4.5 points
Deschutes Countylowest in the state1403.6%0.6 pCi/L−31.2 points
Wallowa County, ORborders it1241.7%2.3 pCi/L+6.9 points
Union County, ORborders it5234.6%2.3 pCi/L−0.2 points
Grant County, ORborders it333.3%3.3 pCi/L−1.5 points
Where Umatilla County's reported results fell, 2021, beside Oregon and the United States
ResultUmatilla County testsUmatilla County shareOregon shareU.S. shareAgainst Oregon
Under 2 pCi/L1021.7%62.9%54.4%−41.2 points
2 to 4 pCi/L2043.5%20.8%21.2%+22.7 points
4 pCi/L and above1634.8%16.3%24.4%+18.5 points
Umatilla County ranked among the 19 Oregon counties with 30 or more tests, by share at or above 4 pCi/L, 2021
CountyRankTestsAt or above 4 pCi/LMedian
Umatilla County1 of 194634.8%2.9 pCi/L
Union County2 of 195234.6%2.3 pCi/L
Clatsop County3 of 193330.3%1.9 pCi/L
Multnomah County4 of 191,62321.3%1.8 pCi/L
Tillamook County5 of 1912619.8%1.4 pCi/L
Hood River County6 of 193119.4%1.0 pCi/L
Washington County7 of 1953915.8%1.1 pCi/L
Yamhill County8 of 198415.5%1.3 pCi/L
Columbia County9 of 193315.2%1.8 pCi/L
Polk County10 of 1910015.0%1.4 pCi/L
Clackamas County11 of 1942214.7%1.2 pCi/L
Umatilla County radon tests by year, against Oregon's pooled share
YearTestsAt or above 4 pCi/LMedianHighestOregon, pooledChange from the row before
20231811.1%1.6 pCi/L10.1 pCi/L18.9%+11.1 points
202260.0%0.8 pCi/L0.8 pCi/L20.2%−34.8 points
20214634.8%2.9 pCi/L34.8 pCi/L16.3%+14.8 points
20204020.0%2.7 pCi/L26.0 pCi/L16.8%−22.9 points
20191442.9%2.7 pCi/L47.9 pCi/L20.2%+30.4 points
2018812.5%0.8 pCi/L11.2 pCi/L19.6%−1.8 points
2017714.3%2.6 pCi/L4.0 pCi/L19.2%−5.7 points
20161020.0%1.8 pCi/L9.7 pCi/L21.5%+10.0 points
20151010.0%1.7 pCi/L6.8 pCi/L27.4%−15.0 points
2014825.0%2.2 pCi/L8.4 pCi/L25.1%First on file

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

Umatilla County, Geology

The ground under Umatilla County

Predicted

USGS's geologic map puts all of Umatilla County's mapped land in one class: moderate radon potential. The map puts 58.2% of Umatilla County in the area it calls Deschutes Umatilla Plateau and 41.8% in Blue Mountains. USGS gives both a radon index of 9, in the moderate band (9 to 11).

USGS's geologic areas under Umatilla County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Deschutes Umatilla PlateauTertiary basalt, basaltic breccia, tuffaceous sedimentary rocks and tuff. Elevated uranium in soils.Moderate958.2%
Blue MountainsTertiary basalt and andesite, tuffaceous sedimentary rocks, and tuff.Moderate941.8%

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

Umatilla County beside the ground around it

Umatilla County has more moderate-potential ground than Oregon as a whole: 100% of its land against 62.3%. Of the 7 counties that border it, none has as large a share of moderate-potential ground; Benton County, WA comes nearest at 100%.

Share of land by USGS radon potential: Umatilla County, the 7 counties bordering it and Oregon
AreaEPA zoneLow potentialModerate potentialHigh potential
Umatilla CountyZone 2None100%None
Union CountyZone 2None100%None
Morrow CountyZone 2None100%None
Walla Walla County, WAZone 2None100%None
Columbia County, WAZone 2None100%None
Benton County, WAZone 2None100%None
Grant CountyZone 20.5%99.5%None
Wallowa CountyZone 3None100%None
Oregon36 counties, pooled by land areaVaries37.5%62.3%None

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

Local help

Umatilla County, Local resources

Radon testing and mitigation in Umatilla County

Listed radon businesses with an address in Umatilla County:

Listed radon professionals by town: Pendleton

What Oregon's program says
Email
Radon.program@dhsoha.state.or.us

What it means

Umatilla County, Questions

Questions about radon in Umatilla County

Are radon levels high in Umatilla County?

In 2023, 11.1% of the radon tests reported to CDC for Umatilla County, Oregon were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.6 pCi/L. Of 19 Oregon counties with 30 or more tests for the same period, none reported a higher share; pooled, the state comes to 16.3%.

Which counties border Umatilla County?

Umatilla County borders 7 counties: Union County, OR, Morrow County, OR, Walla Walla County, WA, Columbia County, WA, Benton County, WA, Grant County, OR and Wallowa County, OR.

Products

Umatilla County, Products

Testing a home in Umatilla County

In Umatilla County, 34.8% of 46 tests reported to CDC in 2021 reached 4 pCi/L, against 16.3% pooled across Oregon. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Umatilla County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Umatilla County homes, compared

Explore

Umatilla County, Bordering counties

Counties bordering Umatilla County

Calculated by Radon411

Umatilla County, Cities and towns

Cities and towns in Umatilla County

The Census Bureau estimates 81,119 residents in Umatilla County for July 1, 2025, 1,227 more than in 2020 (+1.5%). That works out to 25 people per square mile of land. Its largest town, Hermiston, has 19,906 residents, 24.5% of the total. Together its 12 incorporated places hold 72.6% of those residents; the other 27.4% live outside any of them. Reported testing is thin here: 46 tests over 2021, or 0.6 for every 1,000 residents (2025 estimate), where Oregon as a whole comes to 1.0.

From Hermiston to Helix, CDC publishes no figure by town: each reads Umatilla County's.

The cities and towns in Umatilla County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Hermiston19,906+2.3%24.5%
Pendleton16,989−0.1%20.9%
Umatilla8,220+13.3%10.1%
Milton-Freewater7,029−1.1%8.7%
Stanfield2,135−0.6%2.6%
Pilot Rock1,320−1.0%1.6%
Athena1,187−0.6%1.5%
Weston702−1.0%0.9%
Echo625−1.6%0.8%
Adams385−0.5%0.5%
Ukiah218+25.3%0.3%
Helix194+0.5%0.2%

12 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).

Umatilla County, Homes

Homes in Umatilla County

Of Umatilla County's 31,693 homes, 61% are detached houses, against 63% across Oregon; 18% are mobile homes. Half of its homes were built before 1978, close to Oregon's 1980: 29% date from before 1960 and 19% from 2000 or later. 67% of occupied homes are lived in by their owner (Oregon: 63%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Umatilla County, Oregon, 2019 to 2023
HomesUmatilla CountyOregon
Housing units31,6931,838,631
Detached houses61%63%
In buildings of 5 or more11%17%
Mobile homes18%8%
Built before 196029%23%
Built since 200019%24%
Middle year built19781980
Owner-occupied67%63%

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