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Radon Levels in Polk County, Oregon

EPA puts Polk County in Zone 3, its lowest radon zone, and most reported tests there come back low, though 10.1% of 79 (2023) reached 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

    10.1%

    8.8 pts below OR

    Polk
    10.1%
    Oregon
    18.9%

    79 tests, 2023

  • Median result

    1.4pCi/L

    Below action level

    Polk
    1.4 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2023

  • Tests reported

    79

    5th of 14 by tests

    Polk
    79
    Multnomah
    792

    Reported to CDC before any fix, 2023

  • 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 Oregon

    11 of 14

    Middle half

    Polk
    10.1%
    Hood River
    39.0%

    By share, of 14 with 30+ tests

Read a result for Polk County

Starts at Polk County's median, 1.4 pCi/L

1.4pCi/L

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

EPA’s reading of 1.4 pCi/L

Below 2 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 below 2 pCi/L, the level at which EPA says a fix should be considered. Polk County's median reported result, 2023.

Interpret this reading

The data

Polk County, At a glance

Polk County at a glance

Predicted: EPA radon zone

EPA Zone 3: lower predicted potential

is EPA's lowest class, and its forecast for Polk 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 72% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Polk County, 2023

Share of reported tests at or above 4 pCi/L, by year, Polk County
Share of reported tests at or above 4 pCi/L, by year, Polk County
YearShare of reported tests at or above 4 pCi/L
201416.2%
201518.2%
201617.1%
201715.4%
201816.9%
201914.0%
202012.1%
202115.0%
202212.3%
202310.1%

2023: 10.1%. Across these years the share ran from 10.1% to 18.2%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

These are the 79 tests reported to CDC for Polk County over 2023, 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: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).

How to read these figures

Polk County, Compared

Polk County radon figures, compared

Calculated by Radon411

Polk County reports fewer high tests than Oregon overall. 10.1% of its 79 tests in 2023 were at or above 4 pCi/L. That is 8.8 points below the 18.9% pooled from 28 Oregon counties.

Ordered from highest share down, it comes 11th of 14 Oregon counties with 30 or more tests for the same period. Nationally, every county with a figure for the same period pools to 33.4%; Polk County sits 23.3 points below it.

Next door, the shares run from 4.9% in Linn County to 21.2% in Yamhill County, with Lincoln County and Linn County below Polk County. Zone 3 on EPA's map (predicted average under 2 pCi/L) and a 10.1% share point the same way here.

Half the tests came in under 1.4 pCi/L and half over it; the single highest reached 10.1 pCi/L. The rest split 72.2% under 2 pCi/L and 17.7% from 2 to 4 (Oregon: 59.5% and 21.6%). Year by year, 2014 opened at 16.2% and 2023 closed at 10.1% (down 6.1 points), with 2015 the high at 18.2%.

The busiest year on file was 2022, with 219 tests reported; the quietest, 2019, had 57.

Share of reported tests at or above 4 pCi/L by year, Polk County against Oregon2014 to 2023, years with 30 or more tests: Polk County 16.2% to 10.1%, the state's pooled share 18.9% in 2023.
Polk CountyOregon, pooled
Share of reported tests at or above 4 pCi/L by year, Polk County against Oregon: data table
YearTestsPolk County, at or above 4 pCi/LOregon, pooled
201418516.2%25.1%
201514818.2%27.4%
201617017.1%21.5%
201712315.4%19.2%
201813616.9%19.6%
20195714.0%20.2%
202011612.1%16.8%
202110015.0%16.3%
202221912.3%20.2%
20237910.1%18.9%
Polk County against Oregon, the United States and nearby counties, 2023
AreaTestsAt or above 4 pCi/LMedianDifference from Polk County
Polk County7910.1%1.4 pCi/LThis county
Oregon, pooled28 counties, pooled2,32918.9%Not pooled+8.8 points
United States, pooled642 counties, pooled128,74033.4%Not pooled+23.3 points
Hood River Countyhighest in the state4139.0%2.2 pCi/L+28.9 points
Deschutes Countylowest in the state601.7%0.9 pCi/L−8.4 points
Yamhill County, ORborders it3321.2%1.6 pCi/L+11.1 points
Marion County, ORborders it19416.0%1.4 pCi/L+5.9 points
Benton County, ORborders it3215.6%0.9 pCi/L+5.5 points
Tillamook County, ORborders it119.1%1.5 pCi/L−1.0 points
Lincoln County, ORborders it368.3%1.1 pCi/L−1.8 points
Linn County, ORborders it414.9%0.8 pCi/L−5.2 points
Where Polk County's reported results fell, 2023, beside Oregon and the United States
ResultPolk County testsPolk County shareOregon shareU.S. shareAgainst Oregon
Under 2 pCi/L5772.2%59.5%41.4%+12.7 points
2 to 4 pCi/L1417.7%21.6%25.2%−3.9 points
4 pCi/L and above810.1%18.9%33.4%−8.8 points
Polk County ranked among the 14 Oregon counties with 30 or more tests, by share at or above 4 pCi/L, 2023
CountyRankTestsAt or above 4 pCi/LMedian
Yamhill County4 of 143321.2%1.6 pCi/L
Jackson County5 of 144916.3%0.7 pCi/L
Marion County6 of 1419416.0%1.4 pCi/L
Clackamas County7 of 1432115.9%1.6 pCi/L
Benton County8 of 143215.6%0.9 pCi/L
Lane County9 of 145815.5%1.0 pCi/L
Washington County10 of 1439611.4%1.3 pCi/L
Polk County11 of 147910.1%1.4 pCi/L
Lincoln County12 of 14368.3%1.1 pCi/L
Linn County13 of 14414.9%0.8 pCi/L
Deschutes County14 of 14601.7%0.9 pCi/L
Polk County radon tests by year, against Oregon's pooled share
YearTestsAt or above 4 pCi/LMedianHighestOregon, pooledChange from the row before
20237910.1%1.4 pCi/L10.1 pCi/L18.9%−2.2 points
202221912.3%1.5 pCi/L8.2 pCi/L20.2%−2.7 points
202110015.0%1.4 pCi/L17.1 pCi/L16.3%+2.9 points
202011612.1%1.0 pCi/L11.7 pCi/L16.8%−1.9 points
20195714.0%1.2 pCi/L10.3 pCi/L20.2%−2.9 points
201813616.9%1.6 pCi/L27.5 pCi/L19.6%+1.5 points
201712315.4%1.4 pCi/L16.4 pCi/L19.2%−1.7 points
201617017.1%1.7 pCi/L28.9 pCi/L21.5%−1.1 points
201514818.2%1.8 pCi/L19.2 pCi/L27.4%+2.0 points
201418516.2%1.6 pCi/L35.0 pCi/L25.1%First on file

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

Polk County, Geology

The ground under Polk County

Predicted

USGS's geologic map splits Polk County: 71.9% of its land is low radon potential and 28.1% moderate. The map puts 71.9% of Polk County in the area it calls Coast Range and 28.1% in Wilamette Valley. USGS gives the first a radon index of 7, in the low band (5 to 8), and the second 9, in the moderate band (9 to 11).

USGS's geologic areas under Polk County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Coast RangeNorthern Coast Range is marine sedimentary rocks and Tertiary mafic volcanic rocks. Southern Coast Range is Tertiary estuarine and marine sedimentary rocks, feldspathic and micaceous.Low771.9%
Wilamette ValleyGravelly to clayey alluvium with moderately elevated uranium content.Moderate928.1%

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

Polk County beside the ground around it

Oregon as a whole has more moderate-potential ground than Polk County: 62.3% of its land, against 28.1% here. Of the 6 counties that border it, 2 have more moderate-potential ground, Yamhill County the most at 47.6%.

Share of land by USGS radon potential: Polk County, the 6 counties bordering it and Oregon
AreaEPA zoneLow potentialModerate potentialHigh potential
Polk CountyZone 371.9%28.1%None
Lincoln CountyZone 398.9%NoneNone
Yamhill CountyZone 252.4%47.6%None
Benton CountyZone 382.8%17.2%None
Marion CountyZone 358.6%41.4%None
Tillamook CountyZone 397.8%NoneNone
Linn CountyZone 376.6%23.4%None
Oregon36 counties, pooled by land areaVaries37.5%62.3%None

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

Local help

Polk County, Local resources

Radon testing and mitigation in Polk County

Listed radon professionals by town: Salem

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

What it means

Polk County, Questions

Questions about radon in Polk County

Are radon levels high in Polk County?

In 2023, 10.1% of the radon tests reported to CDC for Polk County, Oregon were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.4 pCi/L. Of 14 Oregon counties with 30 or more tests for the same period, 10 reported a higher share; pooled, the state comes to 18.9%.

Which counties border Polk County?

Polk County borders 6 counties: Lincoln County, Yamhill County, Benton County, Marion County, Tillamook County and Linn County.

Products

Polk County, Products

Testing a home in Polk County

In Polk County, 10.1% of 79 tests reported to CDC in 2023 reached 4 pCi/L, against 18.9% pooled across Oregon. 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 Polk County.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Polk County homes, compared

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Polk County, Bordering counties

Counties bordering Polk County

Calculated by Radon411

Polk County, Cities and towns

Cities and towns in Polk County

The Census Bureau estimates 90,037 residents in Polk County for July 1, 2025, 2,054 more than in 2020 (+2.3%). That works out to 122 people per square mile of land. Salem, the largest place on its list (181,779 residents in all), extends beyond Polk County, so no share of the total is worked out for it. Testing is reported here more often than across the state: CDC's 79 reported tests for 2023 come to 0.9 for every 1,000 residents (2025 estimate), against 0.5 for Oregon.

From Salem to Falls City, CDC publishes no figure by town: each reads Polk County's.

The cities and towns in Polk County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Salemextends beyond Polk County181,779+3.3%Counted whole
Dallas17,890+5.2%19.9%
Monmouth11,543+3.6%12.8%
Independence10,195+2.0%11.3%
Willaminaextends beyond Polk County2,276+1.1%Counted whole
Falls City1,042−1.2%1.2%

6 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). A place that extends beyond Polk County is counted whole, so it has no share.

Polk County, Homes

Homes in Polk County

Of Polk County's 34,446 homes, 67% are detached houses, against 63% across Oregon; 14% are in buildings of five or more homes. Much of Polk County is recent building: 32% of its homes have gone up since 2000 and the middle year built is 1989, against 1980 for Oregon. 65% 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 Polk County, Oregon, 2019 to 2023
HomesPolk CountyOregon
Housing units34,4461,838,631
Detached houses67%63%
In buildings of 5 or more14%17%
Mobile homes7%8%
Built before 196015%23%
Built since 200032%24%
Middle year built19891980
Owner-occupied65%63%

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