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Radon Levels in Douglas County, Kansas

EPA puts Douglas County in Zone 1, its highest radon zone, and 25.8% of its 868 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

    25.8%

    6.2 pts below KS

    Douglas
    25.8%
    Kansas
    32.0%

    868 tests, 2022

  • Median result

    1.8pCi/L

    Below action level

    Douglas
    1.8 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2022

  • Tests reported

    868

    3rd of 38 by tests

    Douglas
    868
    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

    29 of 38

    Middle half

    Douglas
    25.8%
    Mitchell
    57.4%

    By share, of 38 with 30+ tests

Read a result for Douglas County

Starts at Douglas County's median, 1.8 pCi/L

1.8pCi/L

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

EPA’s reading of 1.8 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. Douglas County's median reported result, 2022.

Interpret this reading

The data

Douglas County, At a glance

Douglas County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Douglas 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: Moderate across 100% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Douglas County, 2022

Share of reported tests at or above 4 pCi/L, by year, Douglas County
Share of reported tests at or above 4 pCi/L, by year, Douglas County
YearShare of reported tests at or above 4 pCi/L
201623.4%
201724.5%
201829.2%
201923.6%
202028.5%
202130.5%
202225.8%

2022: 25.8%. Across these years the share ran from 23.4% to 30.5%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

These are the 868 tests reported to CDC for Douglas 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

Douglas County, Compared

Douglas County radon figures, compared

Calculated by Radon411

Douglas County's 868 reported tests in 2022 had a middle value of 1.8 pCi/L and a maximum of 89.6 pCi/L, and 25.8% reached 4 pCi/L. Kansas as a whole (96 Kansas counties, pooled) comes to 32.0%: 6.2 points higher than here.

Among its state's counties it ranks 29th 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, 462 tests (53.2%) came in under 2 pCi/L, against 45.8% statewide, and 182 tests (21.0%) fell between 2 and 4, against 22.1% statewide. The busiest year on file was 2021, with 2,901 tests reported; the quietest, 2016, had 850.

EPA's 1993 zone map puts Douglas County in Zone 1, a predicted county average above 4 pCi/L. USGS geology rates 100% of the county's land moderate radon potential.

Next door, the shares run from 26.8% in Leavenworth County to 41.2% in Johnson County. Over 7 years of annual figures the share rose 2.4 points, from 23.4% in 2016 to 25.8% in 2022; its peak was 30.5% in 2021.

CDC also counts 25 tests taken after mitigation in Douglas 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, Douglas County against Kansas2016 to 2022, years with 30 or more tests: Douglas County 23.4% to 25.8%, the state's pooled share 32.0% in 2022.
Douglas CountyKansas, pooled
Share of reported tests at or above 4 pCi/L by year, Douglas County against Kansas: data table
YearTestsDouglas County, at or above 4 pCi/LKansas, pooled
201685023.4%35.4%
20171,49824.5%37.3%
20181,17329.2%37.3%
20191,13623.6%33.7%
202094728.5%31.3%
20212,90130.5%31.8%
202286825.8%32.0%
Douglas County against Kansas, the United States and nearby counties, 2022
AreaTestsAt or above 4 pCi/LMedianDifference from Douglas County
Douglas County86825.8%1.8 pCi/LThis county
Kansas, pooled96 counties, pooled18,38532.0%Not pooled+6.2 points
United States, pooled853 counties, pooled333,14023.9%Not pooled−1.9 points
Mitchell Countyhighest in the state4757.4%6.2 pCi/L+31.6 points
Crawford Countylowest in the state345.9%0.8 pCi/L−19.9 points
Osage County, KSborders it2642.3%3.5 pCi/L+16.5 points
Johnson County, KSborders it5,24041.2%3.0 pCi/L+15.4 points
Miami County, KSborders it21440.2%3.0 pCi/L+14.4 points
Jefferson County, KSborders it5339.6%2.4 pCi/L+13.8 points
Shawnee County, KSborders it38834.5%2.6 pCi/L+8.7 points
Franklin County, KSborders it10634.0%2.1 pCi/L+8.2 points
Leavenworth County, KSborders it51526.8%1.9 pCi/L+1.0 points
Where Douglas County's reported results fell, 2022, beside Kansas and the United States
ResultDouglas County testsDouglas County shareKansas shareU.S. shareAgainst Kansas
Under 2 pCi/L46253.2%45.8%54.5%+7.4 points
2 to 4 pCi/L18221.0%22.1%21.7%−1.1 points
4 pCi/L and above22425.8%32.0%23.9%−6.2 points
Douglas 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
Wyandotte County24 of 3868729.7%2.1 pCi/L
Sumner County25 of 387929.1%2.3 pCi/L
Wabaunsee County26 of 383129.0%2.2 pCi/L
Rice County27 of 385328.3%1.8 pCi/L
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
Douglas County radon tests by year, against Kansas' pooled share
YearTestsAt or above 4 pCi/LMedianHighestKansas, pooledChange from the row before
202286825.8%1.8 pCi/L89.6 pCi/L32.0%−4.7 points
20212,90130.5%2.0 pCi/L80.2 pCi/L31.8%+2.0 points
202094728.5%2.1 pCi/L55.5 pCi/L31.3%+4.9 points
20191,13623.6%1.7 pCi/L31.5 pCi/L33.7%−5.6 points
20181,17329.2%2.0 pCi/L91.5 pCi/L37.3%+4.7 points
20171,49824.5%1.4 pCi/L40.0 pCi/L37.3%+1.1 points
201685023.4%1.9 pCi/L44.6 pCi/L35.4%First on file

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

Douglas County, Geology

The ground under Douglas County

Predicted

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

USGS's geologic areas under Douglas County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Glaciated AreaGlacial till underlain by Pennsylvanian and Permian marine and nonmarine sedimentary shale, sandstone, limestone, coal.Moderate9100%

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

Douglas County beside the ground around it

Across Kansas 59.9% of the land is rated high; none of Douglas County's is. Of the 7 counties that border it, 5 have more high-potential ground, Johnson County the most at 97.6%.

Share of land by USGS radon potential: Douglas County, the 7 counties bordering it and Kansas
AreaEPA zoneLow potentialModerate potentialHigh potential
Douglas CountyZone 1None100%None
Leavenworth CountyZone 1None28.8%71.2%
Johnson CountyZone 1None2.4%97.6%
Shawnee CountyZone 2None79.3%20.7%
Franklin CountyZone 2None100%None
Jefferson CountyZone 2None70.7%29.3%
Miami CountyZone 2None68.6%31.4%
Osage CountyZone 2None100%None
Kansas105 counties, pooled by land areaVariesNone40.1%59.9%

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

Local help

Douglas County, Local resources

Radon testing and mitigation in Douglas County

Listed radon businesses with an address in Douglas County:

Listed radon professionals by town: Lawrence, Baldwin City

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

What it means

Douglas County, Questions

Questions about radon in Douglas County

Are radon levels high in Douglas County?

In 2022, 25.8% of the radon tests reported to CDC for Douglas County, Kansas were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.8 pCi/L. Of 38 Kansas counties with 30 or more tests for the same period, 28 reported a higher share; pooled, the state comes to 32.0%.

Which counties border Douglas County?

Douglas County borders 7 counties: Leavenworth County, Johnson County, Shawnee County, Franklin County, Jefferson County, Miami County and Osage County.

Products

Douglas County, Products

Testing a home in Douglas County

In Douglas County, 25.8% of 868 tests reported to CDC in 2022 reached 4 pCi/L, against 32.0% pooled across Kansas. In Zone 1 the year-round level in Douglas 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

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

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Douglas County, Bordering counties

Counties bordering Douglas County

Calculated by Radon411

Douglas County, Cities and towns

Cities and towns in Douglas County

The Census Bureau estimates 120,920 residents in Douglas County for July 1, 2025, 2,139 more than in 2020 (+1.8%). That works out to 265 people per square mile of land. Lawrence alone is home to 96,367 of them, 79.7% of the total. Together its 4 incorporated places hold 89.6% of those residents; the other 10.4% live outside any of them. CDC's 868 reported tests for 2022 work out to 7.2 per 1,000 residents (2025 estimate), close to Kansas' 6.2.

From Lawrence to Lecompton, CDC publishes no figure by town: each reads Douglas County's.

The cities and towns in Douglas County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Lawrence96,367+1.5%79.7%
Eudora6,506+1.4%5.4%
Baldwin City4,946+2.6%4.1%
Lecompton572+0.9%0.5%

4 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).

Douglas County, Homes

Homes in Douglas County

Fewer than six in ten of Douglas County's 53,308 homes are detached houses (53%, against 72% across Kansas); the rest are attached, in shared buildings or mobile. Much of Douglas County is recent building: 30% 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 50% (Kansas: 67%). A tenant can run a test; a fix is the landlord's to make.

Homes in Douglas County, Kansas, 2019 to 2023
HomesDouglas CountyKansas
Housing units53,3081,285,221
Detached houses53%72%
In buildings of 5 or more27%13%
Mobile homes2%4%
Built before 196018%33%
Built since 200030%20%
Middle year built19881975
Owner-occupied50%67%

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