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Radon Levels in Geary County, Kansas

EPA puts Geary County in Zone 1, its highest radon zone, and 25.2% of its 365 reported radon tests (2022) were 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

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  • Share at 4+ pCi/L

    25.2%

    6.8 pts below KS

    Geary
    25.2%
    Kansas
    32.0%

    365 tests, 2022

  • Median result

    1.9pCi/L

    Below action level

    Geary
    1.9 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2022

  • Tests reported

    365

    10th of 38 by tests

    Geary
    365
    Johnson
    5,240

    Reported to CDC before any fix, 2022

  • EPA radon zone

    Zone 1

    Highest potential

    1. Zone 1
    2. 2
    3. 3

    1 highest, 3 lowest

    EPA predicts over 4 pCi/L indoors

  • Rank in Kansas

    33 of 38

    Lowest quarter

    Geary
    25.2%
    Mitchell
    57.4%

    By share, of 38 with 30+ tests

Read a result for Geary County

Starts at Geary County's median, 1.9 pCi/L

1.9pCi/L

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

EPA’s reading of 1.9 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. Geary County's median reported result, 2022.

Interpret this reading

The data

Geary County, At a glance

Geary County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Geary County in and predicts an average indoor of greater than 4 pCi/L (greater than 150 Bq/m³) across the county. That is one forecast for the whole county, not a reading of any address in it; homes above EPA's turn up in all three zones.

USGS geologic potential: High across 87% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Geary County, 2022

Share of reported tests at or above 4 pCi/L, by year, Geary County
Share of reported tests at or above 4 pCi/L, by year, Geary County
YearShare of reported tests at or above 4 pCi/L
201628.9%
201731.7%
201832.0%
201930.9%
202029.7%
202129.6%
202225.2%

2022: 25.2%. Across these years the share ran from 25.2% to 32.0%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

These are the 365 tests reported to CDC for Geary County over 2022, 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: 2022. Measured data period: 2016 to 2022 (every CDC figure on file).

How to read these figures

Geary County, Compared

Geary County radon figures, compared

Calculated by Radon411

Geary County's 365 reported tests in 2022 had a middle value of 1.9 pCi/L and a maximum of 42.0 pCi/L, and 25.2% reached 4 pCi/L. Kansas as a whole (96 Kansas counties, pooled) comes to 32.0%: 6.8 points higher than here.

Among its state's counties it ranks 33rd of 38 Kansas counties with 30 or more tests for the same period. Statewide for the same period, Mitchell County reported the highest share (57.4%) and Crawford County the lowest (5.9%).

Below the action level, 187 tests (51.2%) came in under 2 pCi/L, against 45.8% statewide, and 86 tests (23.6%) fell between 2 and 4, against 22.1% statewide. The busiest year on file was 2021, with 1,134 tests reported; the quietest, 2016, had 149.

EPA's 1993 zone map puts Geary County in Zone 1, a predicted county average above 4 pCi/L. USGS geology rates 87% of the county's land high radon potential.

Next door, the shares run from 29.0% in Wabaunsee County to 55.8% in Clay County. Over 7 years of annual figures the share fell 3.7 points, from 28.9% in 2016 to 25.2% in 2022; its peak was 32.0% in 2018.

CDC also counts 64 tests taken after mitigation in Geary County for the same period: tests in homes where a fix was already in.

Share of reported tests at or above 4 pCi/L by year, Geary County against Kansas2016 to 2022, years with 30 or more tests: Geary County 28.9% to 25.2%, the state's pooled share 32.0% in 2022.
Geary CountyKansas, pooled
Share of reported tests at or above 4 pCi/L by year, Geary County against Kansas: data table
YearTestsGeary County, at or above 4 pCi/LKansas, pooled
201614928.9%35.4%
201722431.7%37.3%
201822532.0%37.3%
201916230.9%33.7%
202026329.7%31.3%
20211,13429.6%31.8%
202236525.2%32.0%
Geary County against Kansas, the United States and nearby counties, 2022
AreaTestsAt or above 4 pCi/LMedianDifference from Geary County
Geary County36525.2%1.9 pCi/LThis county
Kansas, pooled96 counties, pooled18,38532.0%Not pooled+6.8 points
United States, pooled853 counties, pooled333,14023.9%Not pooled−1.3 points
Mitchell Countyhighest in the state4757.4%6.2 pCi/L+32.2 points
Crawford Countylowest in the state345.9%0.8 pCi/L−19.3 points
Clay County, KSborders it7755.8%4.8 pCi/L+30.6 points
Morris County, KSborders it2343.5%3.5 pCi/L+18.3 points
Dickinson County, KSborders it11338.9%2.7 pCi/L+13.7 points
Riley County, KSborders it80031.3%1.9 pCi/L+6.1 points
Wabaunsee County, KSborders it3129.0%2.2 pCi/L+3.8 points
Where Geary County's reported results fell, 2022, beside Kansas and the United States
ResultGeary County testsGeary County shareKansas shareU.S. shareAgainst Kansas
Under 2 pCi/L18751.2%45.8%54.5%+5.4 points
2 to 4 pCi/L8623.6%22.1%21.7%+1.5 points
4 pCi/L and above9225.2%32.0%23.9%−6.8 points
Geary County ranked among the 38 Kansas counties with 30 or more tests, by share at or above 4 pCi/L, 2022
CountyRankTestsAt or above 4 pCi/LMedian
Leavenworth County28 of 3851526.8%1.9 pCi/L
Douglas County29 of 3886825.8%1.8 pCi/L
Butler County30 of 3855025.5%2.1 pCi/L
Reno County31 of 3824025.4%2.2 pCi/L
Pottawatomie County32 of 3820625.2%1.7 pCi/L
Geary County33 of 3836525.2%1.9 pCi/L
Finney County34 of 387623.7%3.0 pCi/L
Sedgwick County35 of 384,91118.4%1.3 pCi/L
Montgomery County36 of 386911.6%0.8 pCi/L
Allen County37 of 38348.8%0.9 pCi/L
Crawford County38 of 38345.9%0.8 pCi/L
Geary County radon tests by year, against Kansas' pooled share
YearTestsAt or above 4 pCi/LMedianHighestKansas, pooledChange from the row before
202236525.2%1.9 pCi/L42.0 pCi/L32.0%−4.4 points
20211,13429.6%2.2 pCi/L42.2 pCi/L31.8%−0.1 points
202026329.7%2.3 pCi/L18.4 pCi/L31.3%−1.2 points
201916230.9%2.9 pCi/L21.4 pCi/L33.7%−1.1 points
201822532.0%2.6 pCi/L21.5 pCi/L37.3%+0.3 points
201722431.7%2.0 pCi/L21.9 pCi/L37.3%+2.8 points
201614928.9%2.5 pCi/L15.2 pCi/L35.4%First on file

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

Geary County, Geology

The ground under Geary County

Predicted

Most of the ground under Geary County is one class on USGS's geologic map: 87.2% of its land is high radon potential, with 12.8% moderate. The map puts 87.2% of Geary County in the area it calls Mid-Continent Rift Zone and 12.8% in Glaciated Area. USGS gives the first a radon index of 12, in the high band (12 to 17), and the second 9, in the moderate band (9 to 11).

USGS's geologic areas under Geary County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Mid-Continent Rift ZoneFaulted and fractured Permian limestone, dolomite, shale, and sandstone related to the Mid-Continent Rift zone.High1287.2%
Glaciated AreaGlacial till underlain by Pennsylvanian and Permian marine and nonmarine sedimentary shale, sandstone, limestone, coal.Moderate912.8%

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

Geary County beside the ground around it

Geary County has more high-potential ground than Kansas as a whole: 87.2% of its land against 59.9%. Of the 5 counties that border it, 2 have more high-potential ground, Dickinson County the most at 100%.

Share of land by USGS radon potential: Geary County, the 5 counties bordering it and Kansas
AreaEPA zoneLow potentialModerate potentialHigh potential
Geary CountyZone 1None12.8%87.2%
Riley CountyZone 1NoneNone100%
Dickinson CountyZone 1NoneNone100%
Morris CountyZone 2None80.0%20.0%
Wabaunsee CountyZone 2None62.4%37.6%
Clay CountyZone 1None34.7%65.3%
Kansas105 counties, pooled by land areaVariesNone40.1%59.9%

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

Local help

Geary County, Local resources

Radon testing and mitigation in Geary County

Listed radon businesses with an address in Geary County:

Listed radon professionals by town: Junction City

What Kansas's program says
Phone
(800) 693-5343

What it means

Geary County, Questions

Questions about radon in Geary County

Are radon levels high in Geary County?

In 2022, 25.2% of the radon tests reported to CDC for Geary County, Kansas were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.9 pCi/L. Of 38 Kansas counties with 30 or more tests for the same period, 32 reported a higher share; pooled, the state comes to 32.0%.

Which counties border Geary County?

Geary County borders 5 counties: Riley County, Dickinson County, Morris County, Wabaunsee County and Clay County.

Products

Geary County, Products

Testing a home in Geary County

In Geary County, 25.2% of 365 tests reported to CDC in 2022 reached 4 pCi/L, against 32.0% pooled across Kansas. In Zone 1 the year-round level in Geary County is the one to know: a long-term test (more than 90 days) or a monitor, with a short-term kit for a first answer.

Test kits and monitors3

See every kit and monitor

Geary County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Geary County

Explore

Geary County, Bordering counties

Counties bordering Geary County

Calculated by Radon411

Geary County, Cities and towns

Cities and towns in Geary County

About 36,338 people live in Geary County by the Census Bureau's estimate for July 1, 2025, 430 fewer than in 2020 (−1.2%). That works out to 94 people per square mile of land. Junction City alone is home to 22,583 of them, 62.1% of the total. Together its 3 incorporated places hold 67.9% of those residents; the other 32.1% live outside any of them. Testing is reported here more often than across the state: CDC's 365 reported tests for 2022 come to 10.0 for every 1,000 residents (2025 estimate), against 6.2 for Kansas.

From Junction City to Milford, CDC publishes no figure by town: each reads Geary County's.

The cities and towns in Geary County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Junction City22,583−1.6%62.1%
Grandview Plaza1,685−1.1%4.6%
Milford404−0.7%1.1%

3 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).

Geary County, Homes

Homes in Geary County

Fewer than six in ten of Geary County's 15,917 homes are detached houses (50%, against 72% across Kansas); the rest are attached, in shared buildings or mobile. Much of Geary County is recent building: 40% of its homes have gone up since 2000 and the middle year built is 1988, against 1975 for Kansas. Most occupied homes here are rented: owners live in 43% (Kansas: 67%). A tenant can run a test; a fix is the landlord's to make.

Homes in Geary County, Kansas, 2019 to 2023
HomesGeary CountyKansas
Housing units15,9171,285,221
Detached houses50%72%
In buildings of 5 or more18%13%
Mobile homes6%4%
Built before 196022%33%
Built since 200040%20%
Middle year built19881975
Owner-occupied43%67%

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