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Radon Levels in Dearborn County, Indiana

EPA puts Dearborn County in Zone 2, its middle radon zone, and 30.1% of its 136 reported radon tests (2008 to 2017, laboratory totals) 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

    30.1%

    8.8 pts below IN

    Dearborn
    30.1%
    Indiana
    38.9%

    136 tests, 2008 to 2017

  • Median result

    2.6pCi/L

    Below action level

    Dearborn
    2.6 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    136

    39th of 69 by tests

    Dearborn
    136
    St. Joseph
    7,346

    Reported to CDC before any fix, 2008 to 2017

  • 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 Indiana

    61 of 69

    Lowest quarter

    Dearborn
    30.1%
    Miami
    63.3%

    By share, of 69 with 30+ tests

Read a result for Dearborn County

Starts at Dearborn County's median, 2.6 pCi/L

2.6pCi/L

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

EPA’s reading of 2.6 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. Dearborn County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Dearborn County, At a glance

Dearborn County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Dearborn 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 Dearborn County, 2008 to 2017, laboratory

Reported results by concentration band, Dearborn County, 2008 to 2017, laboratory
Under 2 pCi/L: 34%2 to 4 pCi/L: 36%4 pCi/L and above: 30%

Of 136 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Dearborn County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L4633.8%
2 to 4 pCi/L4936.0%
4 pCi/L and above4130.1%
What these figures count

These are the 136 tests reported to CDC for Dearborn County over 2008 to 2017 (laboratory totals), 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: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).

How to read these figures

Dearborn County, Compared

Dearborn County radon figures, compared

Calculated by Radon411

In Dearborn County, about 3 in 10 reported tests over the 2008 to 2017 laboratory totals (41 of 136) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 5.6 points lower. Across 92 Indiana counties pooled together, 38.9% of tests reached that level, so Dearborn County runs 8.8 points below its state.

Of 5 neighbours with a figure, 4 reported a larger share at or above 4 pCi/L and 1 a smaller one; the spread is 28.0% (Franklin County) to 54.3% (Butler County, OH). By share, Dearborn County is 61st of 69 Indiana counties with 30 or more tests for the same period.

Half the tests came in under 2.6 pCi/L and half over it; the single highest reached 20.3 pCi/L. Below the action level, 46 tests (33.8%) came in under 2 pCi/L, against 32.8% statewide, and 49 tests (36.0%) fell between 2 and 4, against 28.3% statewide.

Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 30.1% share point the same way here. USGS geology rates 100% of the county's land moderate radon potential. CDC also counts 8 tests taken after mitigation in Dearborn County for the same period: tests in homes where a fix was already in.

CDC's ten-year totals for Dearborn County went from 122 tests (2005 to 2014) to 136 (2008 to 2017), the share going from 25.4% to 30.1%.

Dearborn County against Indiana, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Dearborn County
Dearborn County13630.1%2.6 pCi/LThis county
Indiana, pooled92 counties, pooled43,14838.9%Not pooled+8.8 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+5.6 points
Miami Countyhighest in the state3063.3%5.3 pCi/L+33.2 points
Jasper Countylowest in the state7114.1%1.2 pCi/L−16.0 points
Butler County, OHborders it1,95354.3%4.4 pCi/L+24.2 points
Ohio County, INborders it2152.4%4.1 pCi/L+22.3 points
Boone County, KYborders it1,43442.9%3.5 pCi/L+12.8 points
Ripley County, INborders it6835.3%2.9 pCi/L+5.2 points
Hamilton County, OHborders it3,75434.7%2.8 pCi/L+4.6 points
Franklin County, INborders it5028.0%2.1 pCi/L−2.1 points
Where Dearborn County's reported results fell, 2008 to 2017, laboratory, beside Indiana and the United States
ResultDearborn County testsDearborn County shareIndiana shareU.S. shareAgainst Indiana
Under 2 pCi/L4633.8%32.8%39.6%+1.0 points
2 to 4 pCi/L4936.0%28.3%24.7%+7.7 points
4 pCi/L and above4130.1%38.9%35.7%−8.8 points
Dearborn County ranked among the 69 Indiana counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Monroe County56 of 692,37534.2%2.8 pCi/L
Cass County57 of 699134.1%2.6 pCi/L
Hancock County58 of 6927133.9%2.6 pCi/L
Decatur County59 of 696333.3%2.8 pCi/L
Greene County60 of 694932.7%3.0 pCi/L
Dearborn County61 of 6913630.1%2.6 pCi/L
St. Joseph County62 of 697,34629.3%2.7 pCi/L
Franklin County63 of 695028.0%2.1 pCi/L
Jackson County64 of 698827.3%2.8 pCi/L
Brown County65 of 6911225.9%2.8 pCi/L
Vanderburgh County66 of 691,50524.4%2.4 pCi/L
Dearborn County ten-year laboratory totals, against Indiana's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestIndiana, pooledChange from the row before
2008 to 201713630.1%2.6 pCi/L20.3 pCi/L38.9%−1.5 points
2007 to 201613331.6%2.6 pCi/L20.3 pCi/L39.2%+3.5 points
2006 to 201512828.1%2.5 pCi/L20.3 pCi/L39.6%+2.7 points
2005 to 201412225.4%2.4 pCi/L14.0 pCi/L39.3%First on file

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

Dearborn County, Geology

The ground under Dearborn County

Predicted

USGS's geologic map puts all of Dearborn County's mapped land in one class: moderate radon potential. All of it lies in the area the map calls Dearborn Upland, to which USGS gives a radon index of 10, in the moderate band (9 to 11).

USGS's geologic areas under Dearborn County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Dearborn UplandOrdovician through Devonian limestone, dolostone, and gray shale, and pre-Wisconsinan glacial deposits.Moderate10100%

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

Dearborn County beside the ground around it

Across Indiana 56.6% of the land is rated high; none of Dearborn County's is. Of the 6 counties that border it, 3 have more high-potential ground, Butler County, OH the most at 99.8%.

Share of land by USGS radon potential: Dearborn County, the 6 counties bordering it and Indiana
AreaEPA zoneLow potentialModerate potentialHigh potential
Dearborn CountyZone 2None100%None
Ohio CountyZone 2None100%None
Franklin CountyZone 2None63.0%37.0%
Ripley CountyZone 2None100%None
Boone County, KYZone 2None100%None
Hamilton County, OHZone 1None88.5%11.5%
Butler County, OHZone 1None0.2%99.8%
Indiana92 counties, pooled by land areaVariesNone43.4%56.6%

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

Local help

Dearborn County, Local resources

Radon testing and mitigation in Dearborn County

Listed radon businesses with an address in Dearborn County:

Listed radon professionals by town: Lawrenceburg

What Indiana's program says
Phone
1-800-272-9723
Licensing of radon professionals
According to the Indiana Radon Rule, 410 IAC 5.1, everyone who is serving Indiana by doing radon testing, analysis and mitigation (radon reduction) in residential structures must be certified by the Indiana State Department of Health.

What it means

Dearborn County, Questions

Questions about radon in Dearborn County

Are radon levels high in Dearborn County?

Over the 2008 to 2017 laboratory totals, 30.1% of the radon tests reported to CDC for Dearborn County, Indiana were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.6 pCi/L. Of 69 Indiana counties with 30 or more tests for the same period, 60 reported a higher share; pooled, the state comes to 38.9%.

Which counties border Dearborn County?

Dearborn County borders 6 counties: Ohio County, IN, Franklin County, IN, Ripley County, IN, Boone County, KY, Hamilton County, OH and Butler County, OH.

Products

Dearborn County, Products

Testing a home in Dearborn County

In Dearborn County, 30.1% of 136 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 38.9% pooled across Indiana. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Dearborn County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Dearborn County homes, compared

Explore

Dearborn County, Bordering counties

Counties bordering Dearborn County

Calculated by Radon411

Dearborn County, Cities and towns

Cities and towns in Dearborn County

The Census Bureau estimates 51,609 residents in Dearborn County for July 1, 2025, 855 more than in 2020 (+1.7%). That works out to 169 people per square mile of land. No town dominates: Lawrenceburg, the largest, has 5,243 residents, 10.2% of the total. Together its 7 incorporated places hold 31.9% of those residents; the other 68.1% live outside any of them. Reported testing is thin here: 136 tests over 2008 to 2017, or 2.6 for every 1,000 residents (2025 estimate), where Indiana as a whole comes to 6.2.

From Lawrenceburg to West Harrison, CDC publishes no figure by town: each reads Dearborn County's.

The cities and towns in Dearborn County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Lawrenceburg5,243+2.1%10.2%
Greendale4,598−0.2%8.9%
Aurora3,533+1.4%6.8%
Dillsboro1,375+0.4%2.7%
Moores Hill694+2.4%1.3%
St. Leon672+2.1%1.3%
West Harrison334+1.2%0.6%

7 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).

Dearborn County, Homes

Homes in Dearborn County

Dearborn County is a place of houses on their own lots: 82% of its 20,965 homes are detached single-family houses, against 73% across Indiana. Half of its homes were built before 1982, close to Indiana's 1976: 27% date from before 1960 and 22% from 2000 or later. Owners live in 85% of the occupied homes (Indiana: 70%), so for most households a test and a fix are their own to order.

Homes in Dearborn County, Indiana, 2019 to 2023
HomesDearborn CountyIndiana
Housing units20,9652,953,344
Detached houses82%73%
In buildings of 5 or more7%13%
Mobile homes3%4%
Built before 196027%32%
Built since 200022%21%
Middle year built19821976
Owner-occupied85%70%

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