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Radon Levels in Clinton County, Ohio

EPA puts Clinton County in Zone 1, its highest radon zone, and high results are common there: 52.4% of the 103 radon tests reported to CDC (2008 to 2017, laboratory totals) 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

How to test this homeFind a certified tester

  • Share at 4+ pCi/L

    52.4%

    0.1 pts above OH

    Clinton
    52.4%
    Ohio
    52.3%

    103 tests, 2008 to 2017

  • Median result

    4.2pCi/L

    Action level reached

    Clinton
    4.2 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    103

    62nd of 79 by tests

    Clinton
    103
    Franklin
    16,142

    Reported to CDC before any fix, 2008 to 2017

  • 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 Ohio

    45 of 79

    Middle half

    Clinton
    52.4%
    Pickaway
    81.4%

    By share, of 79 with 30+ tests

Read a result for Clinton County

Starts at Clinton County's median, 4.2 pCi/L

4.2pCi/L

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

EPA’s reading of 4.2 pCi/L

At or above 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 at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. Clinton County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Clinton County, At a glance

Clinton County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Clinton 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 74% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Clinton County, 2008 to 2017, laboratory

Reported results by concentration band, Clinton County, 2008 to 2017, laboratory
Under 2 pCi/L: 26%2 to 4 pCi/L: 21%4 pCi/L and above: 53%

Of 103 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Clinton County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L2726.2%
2 to 4 pCi/L2221.4%
4 pCi/L and above5452.4%
What these figures count

These are the 103 tests reported to CDC for Clinton 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

Clinton County, Compared

Clinton County radon figures, compared

Calculated by Radon411

More than half: 52.4% of the 103 radon tests reported to CDC for Clinton County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 45th of 79 Ohio counties with 30 or more tests for the same period. That is 0.1 points above the 52.3% pooled from 88 Ohio counties.

The median result, 4.2 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 25.4 pCi/L. The rest split 26.2% under 2 pCi/L and 21.4% from 2 to 4 (Ohio: 23.1% and 24.6%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 52.4% share point the same way here.

3 of its 5 bordering counties with figures ran higher, led by Greene County at 58.6%; Brown County reported 47.1%. Statewide for the same period, Pickaway County reported the highest share (81.4%) and Cuyahoga County the lowest (21.7%).

CDC's ten-year totals for Clinton County went from 98 tests (2005 to 2014) to 103 (2008 to 2017), the share going from 52.0% to 52.4%.

Nationally, every county with a figure for the same period pools to 35.7%; Clinton County sits 16.7 points above it.

Clinton County against Ohio, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Clinton County
Clinton County10352.4%4.2 pCi/LThis county
Ohio, pooled88 counties, pooled98,84052.3%Not pooled−0.1 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−16.7 points
Pickaway Countyhighest in the state18381.4%9.5 pCi/L+29.0 points
Cuyahoga Countylowest in the state10,09221.7%2.0 pCi/L−30.7 points
Greene County, OHborders it2,60258.6%4.9 pCi/L+6.2 points
Fayette County, OHborders it1258.3%5.5 pCi/L+5.9 points
Highland County, OHborders it6756.7%4.8 pCi/L+4.3 points
Warren County, OHborders it2,51252.5%4.2 pCi/L+0.1 points
Clermont County, OHborders it1,36350.0%4.0 pCi/L−2.4 points
Brown County, OHborders it7047.1%3.3 pCi/L−5.3 points
Where Clinton County's reported results fell, 2008 to 2017, laboratory, beside Ohio and the United States
ResultClinton County testsClinton County shareOhio shareU.S. shareAgainst Ohio
Under 2 pCi/L2726.2%23.1%39.6%+3.1 points
2 to 4 pCi/L2221.4%24.6%24.7%−3.2 points
4 pCi/L and above5452.4%52.3%35.7%+0.1 points
Clinton County ranked among the 79 Ohio counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Pike County40 of 795756.1%4.5 pCi/L
Erie County41 of 791,65154.5%4.4 pCi/L
Butler County42 of 791,95354.3%4.4 pCi/L
Hocking County43 of 796053.3%4.0 pCi/L
Warren County44 of 792,51252.5%4.2 pCi/L
Clinton County45 of 7910352.4%4.2 pCi/L
Montgomery County46 of 792,92250.3%4.0 pCi/L
Clermont County47 of 791,36350.0%4.0 pCi/L
Harrison County48 of 794450.0%4.1 pCi/L
Jefferson County49 of 7927149.8%3.9 pCi/L
Columbiana County50 of 7966249.1%3.8 pCi/L
Clinton County ten-year laboratory totals, against Ohio's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestOhio, pooledChange from the row before
2008 to 201710352.4%4.2 pCi/L25.4 pCi/L52.3%−2.1 points
2007 to 201610154.5%4.3 pCi/L33.9 pCi/L52.8%+1.5 points
2006 to 201510053.0%4.4 pCi/L33.9 pCi/L52.9%+1.0 points
2005 to 20149852.0%4.3 pCi/L33.9 pCi/L52.4%First on file

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

Clinton County, Geology

The ground under Clinton County

Predicted

USGS's geologic map splits Clinton County: 74.0% of its land is high radon potential and 26.0% moderate. The map puts 74.0% of Clinton County in the area it calls Till Plains and 26.0% in Till Plains. USGS gives the first a radon index of 14, in the high band (12 to 17), and the second 11, in the moderate band (9 to 11).

USGS's geologic areas under Clinton County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Till PlainsGlacial deposits underlain by Ordovician through Devonian limestone and shale.High1474.0%
Till PlainsOrdovician shale and limestone; glacial till.Moderate1126.0%

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

Clinton County beside the ground around it

Clinton County has more high-potential ground than Ohio as a whole: 74.0% of its land against 62.8%. Of the 6 counties that border it, 2 have more high-potential ground, Fayette County the most at 100%.

Share of land by USGS radon potential: Clinton County, the 6 counties bordering it and Ohio
AreaEPA zoneLow potentialModerate potentialHigh potential
Clinton CountyZone 1None26.0%74.0%
Greene CountyZone 1NoneNone100%
Fayette CountyZone 1NoneNone100%
Highland CountyZone 2None67.8%32.2%
Warren CountyZone 1None40.4%59.6%
Clermont CountyZone 2None100%None
Brown CountyZone 2None100%None
Ohio88 counties, pooled by land areaVariesNone37.2%62.8%

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

Local help

Clinton County, Local resources

Radon testing and mitigation in Clinton County

Listed radon businesses with an address in Clinton County:

Listed radon professionals by town: Midland

What Ohio's program says
Phone
614-728-0272
Email
indoor.radon@odh.ohio.gov
Licensing of radon professionals
This program licenses companies and persons directly involved with the radon testing and mitigation industry.

What it means

Clinton County, Questions

Questions about radon in Clinton County

Are radon levels high in Clinton County?

Over the 2008 to 2017 laboratory totals, 52.4% of the radon tests reported to CDC for Clinton County, Ohio were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.2 pCi/L. Of 79 Ohio counties with 30 or more tests for the same period, 44 reported a higher share; pooled, the state comes to 52.3%.

Which counties border Clinton County?

Clinton County borders 6 counties: Greene County, Fayette County, Highland County, Warren County, Clermont County and Brown County.

Products

Clinton County, Products

Testing a home in Clinton County

In Clinton County, 52.4% of 103 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 52.3% pooled across Ohio. In Zone 1 the year-round level in Clinton 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

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

Explore

Clinton County, Bordering counties

Counties bordering Clinton County

Calculated by Radon411

Clinton County, Cities and towns

Cities and towns in Clinton County

The Census Bureau estimates 42,301 residents in Clinton County for July 1, 2025, 266 more than in 2020 (+0.6%). That works out to 103 people per square mile of land. Its largest town, Wilmington, has 12,802 residents, 30.3% of the total. Reported testing is thin here: 103 tests over 2008 to 2017, or 2.4 for every 1,000 residents (2025 estimate), where Ohio as a whole comes to 8.3.

From Wilmington to Port William, CDC publishes no figure by town: each reads Clinton County's.

The cities and towns in Clinton County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Wilmington12,802+1.1%30.3%
Blanchesterextends beyond Clinton County4,250+0.6%Counted whole
Sabina2,437−2.2%5.8%
Lynchburgextends beyond Clinton County1,538+1.7%Counted whole
New Vienna1,106−1.4%2.6%
Clarksville536+0.4%1.3%
Martinsville404−1.7%1.0%
Midland307−0.3%0.7%
Port William219−1.4%0.5%

9 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 Clinton County is counted whole, so it has no share.

Clinton County, Homes

Homes in Clinton County

Clinton County is a place of houses on their own lots: 77% of its 17,966 homes are detached single-family houses, against 69% across Ohio. Half of its homes were built before 1976, close to Ohio's 1970: 35% date from before 1960 and 17% from 2000 or later. 71% of occupied homes are lived in by their owner (Ohio: 67%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Clinton County, Ohio, 2019 to 2023
HomesClinton CountyOhio
Housing units17,9665,271,573
Detached houses77%69%
In buildings of 5 or more8%15%
Mobile homes7%4%
Built before 196035%38%
Built since 200017%16%
Middle year built19761970
Owner-occupied71%67%

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