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Radon Levels in Holmes County, Ohio

EPA puts Holmes County in Zone 1, its highest radon zone, and high results are common there: 64.2% of the 67 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

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  • Share at 4+ pCi/L

    64.2%

    11.9 pts above OH

    Holmes
    64.2%
    Ohio
    52.3%

    67 tests, 2008 to 2017

  • Median result

    5.8pCi/L

    Action level reached

    Holmes
    5.8 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    67

    68th of 79 by tests

    Holmes
    67
    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

    16 of 79

    Top quarter

    Holmes
    64.2%
    Pickaway
    81.4%

    By share, of 79 with 30+ tests

Read a result for Holmes County

Starts at Holmes County's median, 5.8 pCi/L

5.8pCi/L

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

EPA’s reading of 5.8 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. Holmes County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Holmes County, At a glance

Holmes County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Holmes 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 100% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

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

Reported results by concentration band, Holmes County, 2008 to 2017, laboratory
Under 2 pCi/L: 17%2 to 4 pCi/L: 19%4 pCi/L and above: 64%

Of 67 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Holmes County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L1116.4%
2 to 4 pCi/L1319.4%
4 pCi/L and above4364.2%
What these figures count

These are the 67 tests reported to CDC for Holmes 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

Holmes County, Compared

Holmes County radon figures, compared

Calculated by Radon411

More than half: 64.2% of the 67 radon tests reported to CDC for Holmes County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 16th of 79 Ohio counties with 30 or more tests for the same period. That is 11.9 points above the 52.3% pooled from 88 Ohio counties.

The median result, 5.8 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 122.4 pCi/L. The rest split 16.4% under 2 pCi/L and 19.4% from 2 to 4 (Ohio: 23.1% and 24.6%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 64.2% share point the same way here.

2 of its 6 bordering counties with figures ran higher, led by Knox County at 72.0%; Coshocton County reported 58.9%. 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 Holmes County went from 41 tests (2005 to 2014) to 67 (2008 to 2017), the share going from 51.2% to 64.2%.

Nationally, every county with a figure for the same period pools to 35.7%; Holmes County sits 28.5 points above it. CDC also counts 11 tests taken after mitigation in Holmes County for the same period: tests in homes where a fix was already in.

Holmes County against Ohio, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Holmes County
Holmes County6764.2%5.8 pCi/LThis county
Ohio, pooled88 counties, pooled98,84052.3%Not pooled−11.9 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−28.5 points
Pickaway Countyhighest in the state18381.4%9.5 pCi/L+17.2 points
Cuyahoga Countylowest in the state10,09221.7%2.0 pCi/L−42.5 points
Knox County, OHborders it1,53072.0%8.1 pCi/L+7.8 points
Tuscarawas County, OHborders it54766.4%5.6 pCi/L+2.2 points
Ashland County, OHborders it34062.9%5.4 pCi/L−1.3 points
Wayne County, OHborders it1,07461.8%4.9 pCi/L−2.4 points
Stark County, OHborders it3,31760.1%4.9 pCi/L−4.1 points
Coshocton County, OHborders it11258.9%5.1 pCi/L−5.3 points
Where Holmes County's reported results fell, 2008 to 2017, laboratory, beside Ohio and the United States
ResultHolmes County testsHolmes County shareOhio shareU.S. shareAgainst Ohio
Under 2 pCi/L1116.4%23.1%39.6%−6.7 points
2 to 4 pCi/L1319.4%24.6%24.7%−5.2 points
4 pCi/L and above4364.2%52.3%35.7%+11.9 points
Holmes 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
Ross County11 of 7936867.1%7.0 pCi/L
Tuscarawas County12 of 7954766.4%5.6 pCi/L
Marion County13 of 7926565.3%6.4 pCi/L
Miami County14 of 7969065.2%6.1 pCi/L
Morrow County15 of 7917765.0%5.7 pCi/L
Holmes County16 of 796764.2%5.8 pCi/L
Darke County17 of 7927063.7%5.6 pCi/L
Ashland County18 of 7934062.9%5.4 pCi/L
Preble County19 of 7921262.7%5.5 pCi/L
Richland County20 of 791,32762.2%5.2 pCi/L
Wayne County21 of 791,07461.8%4.9 pCi/L
Holmes County ten-year laboratory totals, against Ohio's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestOhio, pooledChange from the row before
2008 to 20176764.2%5.8 pCi/L122.4 pCi/L52.3%−0.8 points
2007 to 20166065.0%5.8 pCi/L77.3 pCi/L52.8%+4.2 points
2006 to 20155160.8%5.1 pCi/L77.3 pCi/L52.9%+9.6 points
2005 to 20144151.2%4.1 pCi/L77.3 pCi/L52.4%First on file

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

Holmes County, Geology

The ground under Holmes County

Predicted

USGS's geologic map puts all of Holmes County's mapped land in one class: high radon potential. All of it lies in the area the map calls Area of Elevated Radioactivity, to which USGS gives a radon index of 12, in the high band (12 to 17).

USGS's geologic areas under Holmes County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Area of Elevated RadioactivityPennsylvanian shale, sandstone, coal, and limestone.High12100%

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

Holmes County beside the ground around it

Holmes County has more high-potential ground than Ohio as a whole: 100% of its land against 62.8%. Of the 6 counties that border it, none has as large a share of high-potential ground; Tuscarawas County comes nearest at 100%.

Share of land by USGS radon potential: Holmes County, the 6 counties bordering it and Ohio
AreaEPA zoneLow potentialModerate potentialHigh potential
Holmes CountyZone 1NoneNone100%
Coshocton CountyZone 1NoneNone100%
Wayne CountyZone 1None34.6%65.4%
Tuscarawas CountyZone 1NoneNone100%
Knox CountyZone 1NoneNone100%
Ashland CountyZone 1None31.5%68.5%
Stark CountyZone 1None56.2%43.8%
Ohio88 counties, pooled by land areaVariesNone37.2%62.8%

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

Local help

Holmes County, Local resources

Radon testing and mitigation in Holmes County

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

Holmes County, Questions

Questions about radon in Holmes County

Are radon levels high in Holmes County?

Over the 2008 to 2017 laboratory totals, 64.2% of the radon tests reported to CDC for Holmes County, Ohio were at or above 4 pCi/L, and the median reported pre-mitigation result was 5.8 pCi/L. Of 79 Ohio counties with 30 or more tests for the same period, 15 reported a higher share; pooled, the state comes to 52.3%.

Which counties border Holmes County?

Holmes County borders 6 counties: Coshocton County, Wayne County, Tuscarawas County, Knox County, Ashland County and Stark County.

Products

Holmes County, Products

Testing a home in Holmes County

In Holmes County, 64.2% of 67 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 Holmes 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

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

Explore

Holmes County, Bordering counties

Counties bordering Holmes County

Calculated by Radon411

Holmes County, Cities and towns

Cities and towns in Holmes County

The Census Bureau estimates 44,970 residents in Holmes County for July 1, 2025, 731 more than in 2020 (+1.7%). That works out to 106 people per square mile of land. No town dominates: Millersburg, the largest, has 3,295 residents, 7.3% of the total. Reported testing is thin here: 67 tests over 2008 to 2017, or 1.5 for every 1,000 residents (2025 estimate), where Ohio as a whole comes to 8.3.

From Millersburg to Nashville, CDC publishes no figure by town: each reads Holmes County's.

The cities and towns in Holmes County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Millersburg3,295+4.2%7.3%
Loudonvilleextends beyond Holmes County2,733−1.6%Counted whole
Balticextends beyond Holmes County848+0.5%Counted whole
Killbuck816+1.1%1.8%
Holmesville377+0.5%0.8%
Glenmont238+1.7%0.5%
Nashville186+2.2%0.4%

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). A place that extends beyond Holmes County is counted whole, so it has no share.

Holmes County, Homes

Homes in Holmes County

Holmes County is a place of houses on their own lots: 82% of its 14,560 homes are detached single-family houses, against 69% across Ohio. Much of Holmes County is recent building: 29% of its homes have gone up since 2000 and the middle year built is 1986, against 1970 for Ohio. Owners live in 80% of the occupied homes (Ohio: 67%), so for most households a test and a fix are their own to order.

Homes in Holmes County, Ohio, 2019 to 2023
HomesHolmes CountyOhio
Housing units14,5605,271,573
Detached houses82%69%
In buildings of 5 or more3%15%
Mobile homes6%4%
Built before 196026%38%
Built since 200029%16%
Middle year built19861970
Owner-occupied80%67%

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