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Radon Levels in Guernsey County, Ohio

EPA puts Guernsey County in Zone 1, its highest radon zone, and high results are common there: 44.4% of the 117 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

    44.4%

    7.9 pts below OH

    Guernsey
    44.4%
    Ohio
    52.3%

    117 tests, 2008 to 2017

  • Median result

    3.6pCi/L

    Below action level

    Guernsey
    3.6 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    117

    60th of 79 by tests

    Guernsey
    117
    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

    60 of 79

    Lowest quarter

    Guernsey
    44.4%
    Pickaway
    81.4%

    By share, of 79 with 30+ tests

Read a result for Guernsey County

Starts at Guernsey County's median, 3.6 pCi/L

3.6pCi/L

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

EPA’s reading of 3.6 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. Guernsey County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Guernsey County, At a glance

Guernsey County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Guernsey 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 86% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

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

Reported results by concentration band, Guernsey County, 2008 to 2017, laboratory
Under 2 pCi/L: 31%2 to 4 pCi/L: 25%4 pCi/L and above: 44%

Of 117 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Guernsey County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L3630.8%
2 to 4 pCi/L2924.8%
4 pCi/L and above5244.4%
What these figures count

These are the 117 tests reported to CDC for Guernsey 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

Guernsey County, Compared

Guernsey County radon figures, compared

Calculated by Radon411

In Guernsey County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (52 of 117) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 8.7 points higher. Across 88 Ohio counties pooled together, 52.3% of tests reached that level, so Guernsey County runs 7.9 points below its state.

Of 6 neighbours with a figure, 5 reported a larger share at or above 4 pCi/L and 1 a smaller one; the spread is 31.0% (Noble County) to 66.4% (Tuscarawas County). By share, Guernsey County is 60th of 79 Ohio counties with 30 or more tests for the same period.

Half the tests came in under 3.6 pCi/L and half over it; the single highest reached 115.1 pCi/L. Below the action level, 36 tests (30.8%) came in under 2 pCi/L, against 23.1% statewide, and 29 tests (24.8%) fell between 2 and 4, against 24.6% statewide.

Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 44.4% share point the same way here. USGS geology rates 86% of the county's land high radon potential. CDC also counts 12 tests taken after mitigation in Guernsey County for the same period: tests in homes where a fix was already in.

CDC's ten-year totals for Guernsey County went from 120 tests (2005 to 2014) to 117 (2008 to 2017), the share going from 48.3% to 44.4%.

Guernsey County against Ohio, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Guernsey County
Guernsey County11744.4%3.6 pCi/LThis county
Ohio, pooled88 counties, pooled98,84052.3%Not pooled+7.9 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−8.7 points
Pickaway Countyhighest in the state18381.4%9.5 pCi/L+37.0 points
Cuyahoga Countylowest in the state10,09221.7%2.0 pCi/L−22.7 points
Tuscarawas County, OHborders it54766.4%5.6 pCi/L+22.0 points
Coshocton County, OHborders it11258.9%5.1 pCi/L+14.5 points
Muskingum County, OHborders it39156.3%4.9 pCi/L+11.9 points
Harrison County, OHborders it4450.0%4.1 pCi/L+5.6 points
Belmont County, OHborders it69745.2%3.6 pCi/L+0.8 points
Noble County, OHborders it4231.0%2.2 pCi/L−13.4 points
Where Guernsey County's reported results fell, 2008 to 2017, laboratory, beside Ohio and the United States
ResultGuernsey County testsGuernsey County shareOhio shareU.S. shareAgainst Ohio
Under 2 pCi/L3630.8%23.1%39.6%+7.7 points
2 to 4 pCi/L2924.8%24.6%24.7%+0.2 points
4 pCi/L and above5244.4%52.3%35.7%−7.9 points
Guernsey 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
Hancock County55 of 791,38246.2%3.7 pCi/L
Wood County56 of 791,19245.5%3.5 pCi/L
Lorain County57 of 793,30745.4%3.6 pCi/L
Belmont County58 of 7969745.2%3.6 pCi/L
Fulton County59 of 796245.2%3.1 pCi/L
Guernsey County60 of 7911744.4%3.6 pCi/L
Medina County61 of 792,13943.4%3.5 pCi/L
Hardin County62 of 796743.3%3.4 pCi/L
Jackson County63 of 794841.7%3.3 pCi/L
Ottawa County64 of 7954140.3%2.9 pCi/L
Lucas County65 of 791,38140.2%3.0 pCi/L
Guernsey County ten-year laboratory totals, against Ohio's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestOhio, pooledChange from the row before
2008 to 201711744.4%3.6 pCi/L115.1 pCi/L52.3%−4.8 points
2007 to 201612249.2%3.8 pCi/L115.1 pCi/L52.8%+0.8 points
2006 to 201512248.4%3.8 pCi/L115.1 pCi/L52.9%+0.1 points
2005 to 201412048.3%3.8 pCi/L115.1 pCi/L52.4%First on file

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

Guernsey County, Geology

The ground under Guernsey County

Predicted

Most of the ground under Guernsey County is one class on USGS's geologic map: 85.7% of its land is high radon potential, with 14.3% moderate. The map puts 85.7% of Guernsey County in the area it calls Area of Elevated Radioactivity and 14.3% in Unglaciated Plateau. USGS gives the first a radon index of 12, in the high band (12 to 17), and the second 11, in the moderate band (9 to 11).

USGS's geologic areas under Guernsey County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Area of Elevated RadioactivityPennsylvanian shale, sandstone, coal, and limestone.High1285.7%
Unglaciated PlateauMississippian through Permian limestone, dolomite, and shale.Moderate1114.3%

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

Guernsey County beside the ground around it

Guernsey County has more high-potential ground than Ohio as a whole: 85.7% of its land against 62.8%. Of the 6 counties that border it, 3 have more high-potential ground, Harrison County the most at 100%.

Share of land by USGS radon potential: Guernsey County, the 6 counties bordering it and Ohio
AreaEPA zoneLow potentialModerate potentialHigh potential
Guernsey CountyZone 1None14.3%85.7%
Noble CountyZone 2None100%None
Harrison CountyZone 1NoneNone100%
Muskingum CountyZone 1None28.5%71.5%
Belmont CountyZone 1None30.9%69.1%
Tuscarawas CountyZone 1NoneNone100%
Coshocton CountyZone 1NoneNone100%
Ohio88 counties, pooled by land areaVariesNone37.2%62.8%

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

Local help

Guernsey County, Local resources

Radon testing and mitigation in Guernsey County

Listed radon businesses with an address in Guernsey County:

Listed radon professionals by town: Cambridge

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

Guernsey County, Questions

Questions about radon in Guernsey County

Are radon levels high in Guernsey County?

Over the 2008 to 2017 laboratory totals, 44.4% of the radon tests reported to CDC for Guernsey County, Ohio were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.6 pCi/L. Of 79 Ohio counties with 30 or more tests for the same period, 59 reported a higher share; pooled, the state comes to 52.3%.

Which counties border Guernsey County?

Guernsey County borders 6 counties: Noble County, Harrison County, Muskingum County, Belmont County, Tuscarawas County and Coshocton County.

Products

Guernsey County, Products

Testing a home in Guernsey County

In Guernsey County, 44.4% of 117 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 Guernsey 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

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

Explore

Guernsey County, Bordering counties

Counties bordering Guernsey County

Calculated by Radon411

Guernsey County, Cities and towns

Cities and towns in Guernsey County

Guernsey County's population has barely moved since 2020: 38,379 residents on July 1, 2025 against 38,426 then, by the Census Bureau's estimates. That works out to 73 people per square mile of land. Its largest town, Cambridge, has 10,055 residents, 26.2% of the total. Reported testing is thin here: 117 tests over 2008 to 2017, or 3.0 for every 1,000 residents (2025 estimate), where Ohio as a whole comes to 8.3.

From Cambridge to Fairview, CDC publishes no figure by town: each reads Guernsey County's.

The cities and towns in Guernsey County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Cambridge10,055−0.6%26.2%
Byesville2,359−0.4%6.1%
Senecaville407−0.7%1.1%
Pleasant City396−0.8%1.0%
Quaker City375−1.3%1.0%
Cumberland314−0.6%0.8%
Lore City280−1.1%0.7%
Old Washington227−0.9%0.6%
Fairviewextends beyond Guernsey County68LevelCounted whole

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 Guernsey County is counted whole, so it has no share.

Guernsey County, Homes

Homes in Guernsey County

Of Guernsey County's 19,024 homes, 74% are detached houses, against 69% across Ohio; 12% are mobile homes. Half of its homes were built before 1972, close to Ohio's 1970: 38% date from before 1960 and 18% from 2000 or later. 72% 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 Guernsey County, Ohio, 2019 to 2023
HomesGuernsey CountyOhio
Housing units19,0245,271,573
Detached houses74%69%
In buildings of 5 or more6%15%
Mobile homes12%4%
Built before 196038%38%
Built since 200018%16%
Middle year built19721970
Owner-occupied72%67%

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