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Radon Levels in Cole County, Missouri

EPA puts Cole County in Zone 2, its middle radon zone, and only 22 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

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  • Share at 4+ pCi/L

    25.7%

    5.1 pts below MO

    Cole
    25.7%
    Missouri
    30.8%

    790 tests, 2007 to 2016

  • Median result

    2.2pCi/L

    Below action level

    Cole
    2.2 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2007 to 2016

  • Tests reported

    790

    11th of 72 by tests

    Cole
    790
    St. Louis
    16,567

    Reported to CDC before any fix, 2007 to 2016

  • 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 Missouri

    48 of 72

    Middle half

    Cole
    25.7%
    Atchison
    70.5%

    By share, of 72 with 30+ tests

Read a result for Cole County

Starts at Cole County's median, 2.2 pCi/L

2.2pCi/L

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

EPA’s reading of 2.2 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. Cole County's median reported result, 2007 to 2016.

Interpret this readingWhat a fix costs

The data

Cole County, At a glance

Cole County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Cole 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 Cole County, 2023

Share of reported tests at or above 4 pCi/L, by year, Cole County
Share of reported tests at or above 4 pCi/L, by year, Cole County
YearShare of reported tests at or above 4 pCi/L
201431.3%
201523.1%
201618.5%
201726.9%
201833.3%
201925.0%
202020.0%
202123.1%
202241.3%
202340.9%

2023: 40.9%. Across these years the share ran from 18.5% to 41.3%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

Only 22 tests were reported to CDC for Cole 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

Cole County, Compared

Cole County radon figures, compared

Calculated by Radon411

Cole County's 790 reported tests over the 2007 to 2016 laboratory totals had a middle value of 2.2 pCi/L and a maximum of 44.2 pCi/L, and 25.7% reached 4 pCi/L. Missouri as a whole (115 Missouri counties, pooled) comes to 30.8%: 5.1 points higher than here.

The newest figure, in 2023, counts only 22 tests (40.9% at or above 4 pCi/L), too few to compare, so this reading uses the 790-test figure.

Among its state's counties it ranks 48th of 72 Missouri counties with 30 or more tests for the same period. Statewide for the same period, Atchison County reported the highest share (70.5%) and Vernon County the lowest (9.1%).

Below the action level, 359 tests (45.4%) came in under 2 pCi/L, against 41.2% statewide, and 228 tests (28.9%) fell between 2 and 4, against 27.9% statewide. The busiest year on file was 2022, with 63 tests reported; the quietest, 2018, had 9.

EPA's 1993 zone map puts Cole County in Zone 2, a predicted county average between 2 and 4 pCi/L. USGS geology rates 100% of the county's land moderate radon potential.

Next door, the shares run from 14.0% in Miller County to 28.9% in Callaway County, with Boone County, Osage County and Miller County below Cole County.

Cole County against Missouri, the United States and nearby counties, 2007 to 2016, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Cole County
Cole County79025.7%2.2 pCi/LThis county
Missouri, pooled115 counties, pooled54,94630.8%Not pooled+5.1 points
United States, pooled2,666 counties, pooled1,939,02535.8%Not pooled+10.1 points
Atchison Countyhighest in the state8870.5%5.5 pCi/L+44.8 points
Vernon Countylowest in the state339.1%1.2 pCi/L−16.6 points
Callaway County, MOborders it20428.9%1.8 pCi/L+3.2 points
Moniteau County, MOborders it7025.7%2.3 pCi/LLevel
Boone County, MOborders it4,49621.6%1.9 pCi/L−4.1 points
Osage County, MOborders it5514.5%1.5 pCi/L−11.2 points
Miller County, MOborders it13614.0%1.8 pCi/L−11.7 points
Where Cole County's reported results fell, 2007 to 2016, laboratory, beside Missouri and the United States
ResultCole County testsCole County shareMissouri shareU.S. shareAgainst Missouri
Under 2 pCi/L35945.4%41.2%39.6%+4.2 points
2 to 4 pCi/L22828.9%27.9%24.6%+1.0 points
4 pCi/L and above20325.7%30.8%35.8%−5.1 points
Cole County ranked among the 72 Missouri counties with 30 or more tests, by share at or above 4 pCi/L, 2007 to 2016, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Jasper County43 of 7225628.5%2.0 pCi/L
Scott County44 of 724526.7%1.8 pCi/L
St. Louis County45 of 7216,56726.5%2.3 pCi/L
St. Charles County46 of 726,28726.2%2.2 pCi/L
Moniteau County47 of 727025.7%2.3 pCi/L
Cole County48 of 7279025.7%2.2 pCi/L
Johnson County49 of 7226025.4%1.9 pCi/L
Texas County50 of 725625.0%1.4 pCi/L
Monroe County51 of 723724.3%1.7 pCi/L
Washington County51 of 723724.3%1.5 pCi/L
Morgan County53 of 7211323.9%2.3 pCi/L
Cole County radon tests by year, against Missouri's pooled share
YearTestsAt or above 4 pCi/LMedianHighestMissouri, pooledChange from the row before
20232240.9%3.4 pCi/L9.1 pCi/L35.7%−0.4 points
20226341.3%3.2 pCi/L24.7 pCi/L40.8%+18.2 points
20213923.1%2.2 pCi/L11.1 pCi/L31.8%+3.1 points
20201020.0%1.4 pCi/L4.8 pCi/L33.2%−5.0 points
20191225.0%2.5 pCi/L8.6 pCi/L33.5%−8.3 points
2018933.3%2.2 pCi/L4.8 pCi/L42.1%+6.4 points
20172626.9%2.3 pCi/L9.5 pCi/L37.0%+8.4 points
20162718.5%2.6 pCi/L13.4 pCi/L29.8%−4.6 points
20152623.1%2.2 pCi/L13.6 pCi/L27.6%−8.2 points
20141631.3%2.7 pCi/L6.8 pCi/L34.4%First on file

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

Cole County, Geology

The ground under Cole County

Predicted

USGS's geologic map puts all of Cole County's mapped land in one class: moderate radon potential. All of it lies in the area the map calls Salem Plateau, to which USGS gives a radon index of 11, in the moderate band (9 to 11).

USGS's geologic areas under Cole County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Salem PlateauOrdovician dolomite, sandstone, limestone, and shale.Moderate11100%

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

Cole County beside the ground around it

Across Missouri 8.2% of the land is rated high; none of Cole County's is. Of the 5 counties that border it, none has as large a share of moderate-potential ground; Callaway County comes nearest at 100%.

Share of land by USGS radon potential: Cole County, the 5 counties bordering it and Missouri
AreaEPA zoneLow potentialModerate potentialHigh potential
Cole CountyZone 2None100%None
Osage CountyZone 2None100%None
Moniteau CountyZone 2None100%None
Miller CountyZone 2None100%None
Callaway CountyZone 2None100%None
Boone CountyZone 2None100%None
Missouri115 counties, pooled by land areaVaries5.8%86.0%8.2%

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

Local help

Cole County, Local resources

Radon testing and mitigation in Cole County

What Missouri's program says
Phone
573-751-6102
Email
radon@health.mo.gov

What it means

Cole County, Questions

Questions about radon in Cole County

Are radon levels high in Cole County?

In 2023, 40.9% of the radon tests reported to CDC for Cole County, Missouri were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.4 pCi/L. Of 72 Missouri counties with 30 or more tests for the same period, 47 reported a higher share; pooled, the state comes to 30.8%.

Which counties border Cole County?

Cole County borders 5 counties: Osage County, Moniteau County, Miller County, Callaway County and Boone County.

Products

Cole County, Products

Testing a home in Cole County

In Cole County, 25.7% of 790 tests reported to CDC over the 2007 to 2016 laboratory totals reached 4 pCi/L, against 30.8% pooled across Missouri. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Cole County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Cole County homes, compared

Explore

Cole County, Bordering counties

Counties bordering Cole County

Calculated by Radon411

Cole County, Cities and towns

Cities and towns in Cole County

The Census Bureau estimates 77,908 residents in Cole County for July 1, 2025, 1,300 more than in 2020 (+1.7%). That works out to 199 people per square mile of land. Jefferson City, the largest place on its list (42,489 residents in all), extends beyond Cole County, so no share of the total is worked out for it. CDC's 790 reported tests for 2007 to 2016 work out to 10.1 per 1,000 residents (2025 estimate), close to Missouri's 8.8.

From Jefferson City to Lohman, CDC publishes no figure by town: each reads Cole County's.

The cities and towns in Cole County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Jefferson Cityextends beyond Cole County42,489−0.1%Counted whole
Wardsville1,667+3.9%2.1%
St. Martins1,242+3.9%1.6%
Taos1,175+3.7%1.5%
Russellville806+3.5%1.0%
Centertown292+3.5%0.4%
St. Thomas231+4.1%0.3%
Lohman177+3.5%0.2%

8 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 Cole County is counted whole, so it has no share.

Cole County, Homes

Homes in Cole County

Of Cole County's 33,385 homes, 69% are detached houses, against 70% across Missouri; 10% are in buildings of five or more homes. Half of its homes were built before 1981, close to Missouri's 1978: 20% date from before 1960 and 22% from 2000 or later. 67% of occupied homes are lived in by their owner (Missouri: 68%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Cole County, Missouri, 2019 to 2023
HomesCole CountyMissouri
Housing units33,3852,809,501
Detached houses69%70%
In buildings of 5 or more10%13%
Mobile homes2%5%
Built before 196020%28%
Built since 200022%21%
Middle year built19811978
Owner-occupied67%68%

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