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Radon Levels in Miami County, Kansas

EPA puts Miami County in Zone 2, its middle radon zone, and high results are common there: 40.2% of the 214 radon tests reported to CDC (2022) came back 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

    40.2%

    8.2 pts above KS

    Miami
    40.2%
    Kansas
    32.0%

    214 tests, 2022

  • Median result

    3.0pCi/L

    Below action level

    Miami
    3.0 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2022

  • Tests reported

    214

    14th of 38 by tests

    Miami
    214
    Johnson
    5,240

    Reported to CDC before any fix, 2022

  • 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 Kansas

    11 of 38

    Middle half

    Miami
    40.2%
    Mitchell
    57.4%

    By share, of 38 with 30+ tests

Read a result for Miami County

Starts at Miami County's median, 3.0 pCi/L

3.0pCi/L

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

EPA’s reading of 3.0 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. Miami County's median reported result, 2022.

Interpret this readingWhat a fix costs

The data

Miami County, At a glance

Miami County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Miami 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 69% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Miami County, 2022

Share of reported tests at or above 4 pCi/L, by year, Miami County
Share of reported tests at or above 4 pCi/L, by year, Miami County
YearShare of reported tests at or above 4 pCi/L
201644.4%
201737.9%
201831.7%
201935.0%
202035.8%
202134.3%
202240.2%

2022: 40.2%. Across these years the share ran from 31.7% to 44.4%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

These are the 214 tests reported to CDC for Miami 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

Miami County, Compared

Miami County radon figures, compared

Calculated by Radon411

In Miami County, about 4 in 10 reported tests in 2022 (86 of 214) were at or above EPA's action level. Against the national pool of 23.9%, the gap is 16.3 points higher. Across 96 Kansas counties pooled together, 32.0% of tests reached that level, so Miami County runs 8.2 points above its state.

Of 4 neighbours with a figure, 2 reported a larger share at or above 4 pCi/L and 2 a smaller one; the spread is 25.8% (Douglas County) to 61.3% (Cass County, MO). By share, Miami County is 11th of 38 Kansas counties with 30 or more tests for the same period.

Year by year, 2016 opened at 44.4% and 2022 closed at 40.2% (down 4.2 points), with 2016 the high at 44.4%. Half the tests came in under 3.0 pCi/L and half over it; the single highest reached 146.7 pCi/L. Below the action level, 84 tests (39.3%) came in under 2 pCi/L, against 45.8% statewide, and 44 tests (20.6%) fell between 2 and 4, against 22.1% statewide.

Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 40.2% share point the same way here. USGS geology rates 69% of the county's land moderate radon potential. CDC also counts 11 tests taken after mitigation in Miami County for the same period: tests in homes where a fix was already in.

The busiest year on file was 2021, with 753 tests reported; the quietest, 2016, had 169.

Share of reported tests at or above 4 pCi/L by year, Miami County against Kansas2016 to 2022, years with 30 or more tests: Miami County 44.4% to 40.2%, the state's pooled share 32.0% in 2022.
Miami CountyKansas, pooled
Share of reported tests at or above 4 pCi/L by year, Miami County against Kansas: data table
YearTestsMiami County, at or above 4 pCi/LKansas, pooled
201616944.4%35.4%
201731937.9%37.3%
201839431.7%37.3%
201932635.0%33.7%
202024035.8%31.3%
202175334.3%31.8%
202221440.2%32.0%
Miami County against Kansas, the United States and nearby counties, 2022
AreaTestsAt or above 4 pCi/LMedianDifference from Miami County
Miami County21440.2%3.0 pCi/LThis county
Kansas, pooled96 counties, pooled18,38532.0%Not pooled−8.2 points
United States, pooled853 counties, pooled333,14023.9%Not pooled−16.3 points
Mitchell Countyhighest in the state4757.4%6.2 pCi/L+17.2 points
Crawford Countylowest in the state345.9%0.8 pCi/L−34.3 points
Cass County, MOborders it3161.3%6.2 pCi/L+21.1 points
Linn County, KSborders it1553.3%4.0 pCi/L+13.1 points
Anderson County, KSborders it1241.7%2.6 pCi/L+1.5 points
Johnson County, KSborders it5,24041.2%3.0 pCi/L+1.0 points
Franklin County, KSborders it10634.0%2.1 pCi/L−6.2 points
Douglas County, KSborders it86825.8%1.8 pCi/L−14.4 points
Bates County, MOborders it20.0%1.4 pCi/L−40.2 points
Where Miami County's reported results fell, 2022, beside Kansas and the United States
ResultMiami County testsMiami County shareKansas shareU.S. shareAgainst Kansas
Under 2 pCi/L8439.3%45.8%54.5%−6.5 points
2 to 4 pCi/L4420.6%22.1%21.7%−1.5 points
4 pCi/L and above8640.2%32.0%23.9%+8.2 points
Miami 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
Saline County6 of 3872952.3%4.2 pCi/L
McPherson County7 of 3821551.6%4.1 pCi/L
Pawnee County8 of 385343.4%3.7 pCi/L
Atchison County9 of 386041.7%3.3 pCi/L
Johnson County10 of 385,24041.2%3.0 pCi/L
Miami County11 of 3821440.2%3.0 pCi/L
Marion County12 of 384540.0%2.5 pCi/L
Cowley County13 of 3811839.8%3.3 pCi/L
Jefferson County14 of 385339.6%2.4 pCi/L
Dickinson County15 of 3811338.9%2.7 pCi/L
Ford County16 of 385036.0%3.8 pCi/L
Miami County radon tests by year, against Kansas' pooled share
YearTestsAt or above 4 pCi/LMedianHighestKansas, pooledChange from the row before
202221440.2%3.0 pCi/L146.7 pCi/L32.0%+5.9 points
202175334.3%2.2 pCi/L42.1 pCi/L31.8%−1.5 points
202024035.8%2.5 pCi/L40.0 pCi/L31.3%+0.8 points
201932635.0%2.6 pCi/L53.9 pCi/L33.7%+3.3 points
201839431.7%1.7 pCi/L32.0 pCi/L37.3%−6.2 points
201731937.9%2.3 pCi/L62.6 pCi/L37.3%−6.5 points
201616944.4%3.4 pCi/L46.0 pCi/L35.4%First on file

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

Miami County, Geology

The ground under Miami County

Predicted

USGS's geologic map splits Miami County: 68.6% of its land is moderate radon potential and 31.4% high. The map puts 68.6% of Miami County in the area it calls Glaciated Area and 31.4% in Glacial Drift. USGS gives the first a radon index of 9, in the moderate band (9 to 11), and the second 12, in the high band (12 to 17).

USGS's geologic areas under Miami 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.Moderate968.6%
Glacial DriftGlacial drift and loess of varying thickness, largely locally derived from underlying and nearby Paleozoic sedimentary rocks.High1231.4%

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

Miami County beside the ground around it

Kansas as a whole has more high-potential ground than Miami County: 59.9% of its land, against 31.4% here. Of the 7 counties that border it, 2 have more high-potential ground, Johnson County the most at 97.6%.

Share of land by USGS radon potential: Miami County, the 7 counties bordering it and Kansas
AreaEPA zoneLow potentialModerate potentialHigh potential
Miami CountyZone 2None68.6%31.4%
Johnson CountyZone 1None2.4%97.6%
Franklin CountyZone 2None100%None
Cass County, MOZone 1None64.5%35.5%
Linn CountyZone 2None100%None
Douglas CountyZone 1None100%None
Bates County, MOZone 2None99.7%0.3%
Anderson 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

Miami County, Local resources

Radon testing and mitigation in Miami County

Listed radon businesses with an address in Miami County:

Listed radon professionals by town: Louisburg

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

What it means

Miami County, Questions

Questions about radon in Miami County

Are radon levels high in Miami County?

In 2022, 40.2% of the radon tests reported to CDC for Miami County, Kansas were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.0 pCi/L. Of 38 Kansas counties with 30 or more tests for the same period, 10 reported a higher share; pooled, the state comes to 32.0%.

Which counties border Miami County?

Miami County borders 7 counties: Johnson County, KS, Franklin County, KS, Cass County, MO, Linn County, KS, Douglas County, KS, Bates County, MO and Anderson County, KS.

Products

Miami County, Products

Testing a home in Miami County

In Miami County, 40.2% of 214 tests reported to CDC in 2022 reached 4 pCi/L, against 32.0% pooled across Kansas. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Miami County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Miami County homes, compared

Explore

Miami County, Bordering counties

Counties bordering Miami County

Calculated by Radon411

Miami County, Cities and towns

Cities and towns in Miami County

Miami County is growing: the Census Bureau puts it at 36,240 residents on July 1, 2025, up 5.9% from 34,224 in 2020. That works out to 63 people per square mile of land. Spring Hill, the largest place on its list (10,777 residents in all), extends beyond Miami County, so no share of the total is worked out for it. CDC's 214 reported tests for 2022 work out to 5.9 per 1,000 residents (2025 estimate), close to Kansas' 6.2.

From Spring Hill to Fontana, CDC publishes no figure by town: each reads Miami County's.

The cities and towns in Miami County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Spring Hillextends beyond Miami County10,777+31.6%Counted whole
Paola5,880+2.5%16.2%
Louisburg5,299+7.2%14.6%
Osawatomie4,215+1.3%11.6%
Fontana234+4.9%0.6%

5 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 Miami County is counted whole, so it has no share.

Miami County, Homes

Homes in Miami County

Miami County is a place of houses on their own lots: 83% of its 14,090 homes are detached single-family houses, against 72% across Kansas. Much of Miami County is recent building: 29% of its homes have gone up since 2000 and the middle year built is 1985, against 1975 for Kansas. Owners live in 78% of the occupied homes (Kansas: 67%), so for most households a test and a fix are their own to order.

Homes in Miami County, Kansas, 2019 to 2023
HomesMiami CountyKansas
Housing units14,0901,285,221
Detached houses83%72%
In buildings of 5 or more5%13%
Mobile homes5%4%
Built before 196026%33%
Built since 200029%20%
Middle year built19851975
Owner-occupied78%67%

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