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Radon Levels in Harrison County, Ohio

EPA puts Harrison County in Zone 1, its highest radon zone, and high results are common there: 50.0% of the 44 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

    50.0%

    2.3 pts below OH

    Harrison
    50.0%
    Ohio
    52.3%

    44 tests, 2008 to 2017

  • Median result

    4.1pCi/L

    Action level reached

    Harrison
    4.1 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    44

    77th of 79 by tests

    Harrison
    44
    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

    48 of 79

    Middle half

    Harrison
    50.0%
    Pickaway
    81.4%

    By share, of 79 with 30+ tests

Read a result for Harrison County

Starts at Harrison County's median, 4.1 pCi/L

4.1pCi/L

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

EPA’s reading of 4.1 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. Harrison County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Harrison County, At a glance

Harrison County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Harrison 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 Harrison County, 2008 to 2017, laboratory

Reported results by concentration band, Harrison County, 2008 to 2017, laboratory
Under 2 pCi/L: 18%2 to 4 pCi/L: 32%4 pCi/L and above: 50%

Of 44 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Harrison County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L818.2%
2 to 4 pCi/L1431.8%
4 pCi/L and above2250.0%
What these figures count

These are the 44 tests reported to CDC for Harrison 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

Harrison County, Compared

Harrison County radon figures, compared

Calculated by Radon411

More than half: 50.0% of the 44 radon tests reported to CDC for Harrison County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 48th of 79 Ohio counties with 30 or more tests for the same period. That is 2.3 points below the 52.3% pooled from 88 Ohio counties.

The median result, 4.1 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 42.6 pCi/L. The rest split 18.2% under 2 pCi/L and 31.8% from 2 to 4 (Ohio: 23.1% and 24.6%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 50.0% share point the same way here.

2 of its 5 bordering counties with figures ran higher, led by Tuscarawas County at 66.4%; Guernsey County reported 44.4%. 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 Harrison County went from 32 tests (2005 to 2014) to 44 (2008 to 2017), the share going from 56.3% to 50.0%.

Nationally, every county with a figure for the same period pools to 35.7%; Harrison County sits 14.3 points above it.

Harrison County against Ohio, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Harrison County
Harrison County4450.0%4.1 pCi/LThis county
Ohio, pooled88 counties, pooled98,84052.3%Not pooled+2.3 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−14.3 points
Pickaway Countyhighest in the state18381.4%9.5 pCi/L+31.4 points
Cuyahoga Countylowest in the state10,09221.7%2.0 pCi/L−28.3 points
Tuscarawas County, OHborders it54766.4%5.6 pCi/L+16.4 points
Carroll County, OHborders it48657.4%4.8 pCi/L+7.4 points
Jefferson County, OHborders it27149.8%3.9 pCi/L−0.2 points
Belmont County, OHborders it69745.2%3.6 pCi/L−4.8 points
Guernsey County, OHborders it11744.4%3.6 pCi/L−5.6 points
Where Harrison County's reported results fell, 2008 to 2017, laboratory, beside Ohio and the United States
ResultHarrison County testsHarrison County shareOhio shareU.S. shareAgainst Ohio
Under 2 pCi/L818.2%23.1%39.6%−4.9 points
2 to 4 pCi/L1431.8%24.6%24.7%+7.2 points
4 pCi/L and above2250.0%52.3%35.7%−2.3 points
Harrison 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
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
Perry County51 of 799048.9%3.8 pCi/L
Defiance County52 of 797048.6%3.8 pCi/L
Brown County53 of 797047.1%3.3 pCi/L
Harrison County ten-year laboratory totals, against Ohio's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestOhio, pooledChange from the row before
2008 to 20174450.0%4.1 pCi/L42.6 pCi/L52.3%+1.2 points
2007 to 20164148.8%3.7 pCi/L42.6 pCi/L52.8%−5.3 points
2006 to 20153754.1%4.6 pCi/L42.6 pCi/L52.9%−2.2 points
2005 to 20143256.3%4.8 pCi/L42.6 pCi/L52.4%First on file

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

Harrison County, Geology

The ground under Harrison County

Predicted

USGS's geologic map puts all of Harrison 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 Harrison 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.

Harrison County beside the ground around it

Harrison County has more high-potential ground than Ohio as a whole: 100% of its land against 62.8%. Of the 5 counties that border it, none has as large a share of high-potential ground; Jefferson County comes nearest at 100%.

Share of land by USGS radon potential: Harrison County, the 5 counties bordering it and Ohio
AreaEPA zoneLow potentialModerate potentialHigh potential
Harrison CountyZone 1NoneNone100%
Belmont CountyZone 1None30.9%69.1%
Jefferson CountyZone 1NoneNone100%
Carroll CountyZone 1None11.8%88.2%
Tuscarawas CountyZone 1NoneNone100%
Guernsey CountyZone 1None14.3%85.7%
Ohio88 counties, pooled by land areaVariesNone37.2%62.8%

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

Local help

Harrison County, Local resources

Radon testing and mitigation in Harrison County

Listed radon professionals by town: Bowerston

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

Harrison County, Questions

Questions about radon in Harrison County

Are radon levels high in Harrison County?

Over the 2008 to 2017 laboratory totals, 50.0% of the radon tests reported to CDC for Harrison County, Ohio were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.1 pCi/L. Of 79 Ohio counties with 30 or more tests for the same period, 47 reported a higher share; pooled, the state comes to 52.3%.

Which counties border Harrison County?

Harrison County borders 5 counties: Belmont County, Jefferson County, Carroll County, Tuscarawas County and Guernsey County.

Products

Harrison County, Products

Testing a home in Harrison County

In Harrison County, 50.0% of 44 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 Harrison 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

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

Explore

Harrison County, Bordering counties

Counties bordering Harrison County

Calculated by Radon411

Harrison County, Cities and towns

Cities and towns in Harrison County

About 14,070 people live in Harrison County by the Census Bureau's estimate for July 1, 2025, 428 fewer than in 2020 (−3.0%). That works out to 35 people per square mile of land. Its largest town, Cadiz, has 2,960 residents, 21.0% of the total. Reported testing is thin here: 44 tests over 2008 to 2017, or 3.1 for every 1,000 residents (2025 estimate), where Ohio as a whole comes to 8.3.

From Cadiz to Deersville, CDC publishes no figure by town: each reads Harrison County's.

The cities and towns in Harrison County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Cadiz2,960−3.1%21.0%
Hopedale892−3.3%6.3%
Adenaextends beyond Harrison County651−3.0%Counted whole
Scio649−3.6%4.6%
Jewett534−3.4%3.8%
Bowerston349−3.1%2.5%
Freeport314−3.4%2.2%
New Athens214−2.7%1.5%
Harrisville175−2.8%1.2%
Deersville63−3.1%0.4%

10 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 Harrison County is counted whole, so it has no share.

Harrison County, Homes

Homes in Harrison County

Harrison County is a place of houses on their own lots: 81% of its 7,397 homes are detached single-family houses, against 69% across Ohio. Half of its homes were built before 1965, close to Ohio's 1970: 47% date from before 1960 and 17% from 2000 or later. Owners live in 77% of the occupied homes (Ohio: 67%), so for most households a test and a fix are their own to order.

Homes in Harrison County, Ohio, 2019 to 2023
HomesHarrison CountyOhio
Housing units7,3975,271,573
Detached houses81%69%
In buildings of 5 or more2%15%
Mobile homes14%4%
Built before 196047%38%
Built since 200017%16%
Middle year built19651970
Owner-occupied77%67%

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