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Radon Levels in Belmont County, Ohio

EPA puts Belmont County in Zone 1, its highest radon zone, and high results are common there: 45.2% of the 697 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

    45.2%

    7.1 pts below OH

    Belmont
    45.2%
    Ohio
    52.3%

    697 tests, 2008 to 2017

  • Median result

    3.6pCi/L

    Below action level

    Belmont
    3.6 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    697

    30th of 79 by tests

    Belmont
    697
    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

    58 of 79

    Middle half

    Belmont
    45.2%
    Pickaway
    81.4%

    By share, of 79 with 30+ tests

Read a result for Belmont County

Starts at Belmont 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. Belmont County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Belmont County, At a glance

Belmont County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Belmont 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 69% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

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

Reported results by concentration band, Belmont County, 2008 to 2017, laboratory
Under 2 pCi/L: 20%2 to 4 pCi/L: 35%4 pCi/L and above: 45%

Of 697 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Belmont County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L14120.2%
2 to 4 pCi/L24134.6%
4 pCi/L and above31545.2%
What these figures count

These are the 697 tests reported to CDC for Belmont 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

Belmont County, Compared

Belmont County radon figures, compared

Calculated by Radon411

In Belmont County, about 5 in 10 reported tests over the 2008 to 2017 laboratory totals (315 of 697) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 9.5 points higher. Across 88 Ohio counties pooled together, 52.3% of tests reached that level, so Belmont County runs 7.1 points below its state.

Of 7 neighbours with a figure, 3 reported a larger share at or above 4 pCi/L and 4 a smaller one; the spread is 31.0% (Noble County) to 58.3% (Monroe County). By share, Belmont County is 58th 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 119.4 pCi/L. Below the action level, 141 tests (20.2%) came in under 2 pCi/L, against 23.1% statewide, and 241 tests (34.6%) fell between 2 and 4, against 24.6% statewide.

Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 45.2% share point the same way here. USGS geology rates 69% of the county's land high radon potential. CDC also counts 174 tests taken after mitigation in Belmont County for the same period: tests in homes where a fix was already in.

CDC's ten-year totals for Belmont County went from 544 tests (2005 to 2014) to 697 (2008 to 2017), the share going from 46.1% to 45.2%.

Belmont County against Ohio, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Belmont County
Belmont County69745.2%3.6 pCi/LThis county
Ohio, pooled88 counties, pooled98,84052.3%Not pooled+7.1 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−9.5 points
Pickaway Countyhighest in the state18381.4%9.5 pCi/L+36.2 points
Cuyahoga Countylowest in the state10,09221.7%2.0 pCi/L−23.5 points
Monroe County, OHborders it4858.3%5.0 pCi/L+13.1 points
Harrison County, OHborders it4450.0%4.1 pCi/L+4.8 points
Jefferson County, OHborders it27149.8%3.9 pCi/L+4.6 points
Guernsey County, OHborders it11744.4%3.6 pCi/L−0.8 points
Ohio County, WVborders it85340.3%3.2 pCi/L−4.9 points
Marshall County, WVborders it25431.9%2.5 pCi/L−13.3 points
Noble County, OHborders it4231.0%2.2 pCi/L−14.2 points
Where Belmont County's reported results fell, 2008 to 2017, laboratory, beside Ohio and the United States
ResultBelmont County testsBelmont County shareOhio shareU.S. shareAgainst Ohio
Under 2 pCi/L14120.2%23.1%39.6%−2.9 points
2 to 4 pCi/L24134.6%24.6%24.7%+10.0 points
4 pCi/L and above31545.2%52.3%35.7%−7.1 points
Belmont 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
Brown County53 of 797047.1%3.3 pCi/L
Wyandot County54 of 7932046.3%3.6 pCi/L
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
Belmont County ten-year laboratory totals, against Ohio's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestOhio, pooledChange from the row before
2008 to 201769745.2%3.6 pCi/L119.4 pCi/L52.3%+0.6 points
2007 to 201664344.6%3.6 pCi/L119.4 pCi/L52.8%−0.3 points
2006 to 201560244.9%3.5 pCi/L119.4 pCi/L52.9%−1.2 points
2005 to 201454446.1%3.6 pCi/L119.4 pCi/L52.4%First on file

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

Belmont County, Geology

The ground under Belmont County

Predicted

USGS's geologic map splits Belmont County: 69.1% of its land is high radon potential and 30.9% moderate. The map puts 69.1% of Belmont County in the area it calls Area of Elevated Radioactivity and 30.9% 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 Belmont County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Area of Elevated RadioactivityPennsylvanian shale, sandstone, coal, and limestone.High1269.1%
Unglaciated PlateauMississippian through Permian limestone, dolomite, and shale.Moderate1130.9%

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

Belmont County beside the ground around it

On high-potential ground Belmont County is close to Ohio as a whole: 69.1% of its land against 62.8%. Of the 7 counties that border it, 3 have more high-potential ground, Harrison County the most at 100%.

Share of land by USGS radon potential: Belmont County, the 7 counties bordering it and Ohio
AreaEPA zoneLow potentialModerate potentialHigh potential
Belmont CountyZone 1None30.9%69.1%
Harrison CountyZone 1NoneNone100%
Marshall County, WVZone 1None96.8%3.2%
Ohio County, WVZone 1None69.7%30.3%
Monroe CountyZone 2None100%None
Guernsey CountyZone 1None14.3%85.7%
Jefferson CountyZone 1NoneNone100%
Noble 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

Belmont County, Local resources

Radon testing and mitigation in Belmont County

Listed radon businesses with an address in Belmont County:

Listed radon professionals by town: St. Clairsville

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

Belmont County, Questions

Questions about radon in Belmont County

Are radon levels high in Belmont County?

Over the 2008 to 2017 laboratory totals, 45.2% of the radon tests reported to CDC for Belmont 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, 57 reported a higher share; pooled, the state comes to 52.3%.

Which counties border Belmont County?

Belmont County borders 7 counties: Harrison County, OH, Marshall County, WV, Ohio County, WV, Monroe County, OH, Guernsey County, OH, Jefferson County, OH and Noble County, OH.

Products

Belmont County, Products

Testing a home in Belmont County

In Belmont County, 45.2% of 697 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 Belmont 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

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

Explore

Belmont County, Bordering counties

Counties bordering Belmont County

Calculated by Radon411

Belmont County, Cities and towns

Cities and towns in Belmont County

About 64,434 people live in Belmont County by the Census Bureau's estimate for July 1, 2025, 1,851 fewer than in 2020 (−2.8%). That works out to 121 people per square mile of land. No town dominates: Martins Ferry, the largest, has 6,048 residents, 9.4% of the total. CDC's 697 reported tests for 2008 to 2017 work out to 10.8 per 1,000 residents (2025 estimate), close to Ohio's 8.3.

From Martins Ferry to Fairview, CDC publishes no figure by town: each reads Belmont County's.

The 12 largest cities and towns in Belmont County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Martins Ferry6,048−3.0%9.4%
St. Clairsville4,926−2.9%7.6%
Barnesville3,861−3.5%6.0%
Bellaire3,738−3.3%5.8%
Shadyside3,334−3.0%5.2%
Bridgeport1,523−3.3%2.4%
Powhatan Point1,407−3.0%2.2%
Bethesda1,179−2.6%1.8%
Yorkvilleextends beyond Belmont County933−3.4%Counted whole
Flushing803−3.1%1.2%
Brookside523−3.5%0.8%
Belmont399−3.4%0.6%
  • Holloway
  • Morristown
  • Wilson (part)
  • Fairview (part)

16 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. “(part)” marks a place that extends into another county. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025). A place that extends beyond Belmont County is counted whole, so it has no share.

Belmont County, Homes

Homes in Belmont County

Belmont County is a place of houses on their own lots: 77% of its 31,599 homes are detached single-family houses, against 69% across Ohio. Half of its homes were built before 1964, close to Ohio's 1970: 47% date from before 1960 and 13% from 2000 or later. 74% 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 Belmont County, Ohio, 2019 to 2023
HomesBelmont CountyOhio
Housing units31,5995,271,573
Detached houses77%69%
In buildings of 5 or more7%15%
Mobile homes7%4%
Built before 196047%38%
Built since 200013%16%
Middle year built19641970
Owner-occupied74%67%

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