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Radon Levels in Marshall County, West Virginia

EPA puts Marshall County in Zone 1, its highest radon zone, and 31.9% of its 254 reported radon tests (2008 to 2017, laboratory totals) were 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

    31.9%

    5.6 pts below WV

    Marshall
    31.9%
    WV
    37.5%

    254 tests, 2008 to 2017

  • Median result

    2.5pCi/L

    Below action level

    Marshall
    2.5 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    254

    7th of 27 by tests

    Marshall
    254
    Berkeley
    2,888

    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 WV

    15 of 27

    Middle half

    Marshall
    31.9%
    Morgan
    58.1%

    By share, of 27 with 30+ tests

Read a result for Marshall County

Starts at Marshall County's median, 2.5 pCi/L

2.5pCi/L

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

EPA’s reading of 2.5 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. Marshall County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Marshall County, At a glance

Marshall County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Marshall 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: Moderate across 97% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

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

Reported results by concentration band, Marshall County, 2008 to 2017, laboratory
Under 2 pCi/L: 37%2 to 4 pCi/L: 31%4 pCi/L and above: 32%

Of 254 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Marshall County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L9336.6%
2 to 4 pCi/L8031.5%
4 pCi/L and above8131.9%
What these figures count

These are the 254 tests reported to CDC for Marshall 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

Marshall County, Compared

Marshall County radon figures, compared

Calculated by Radon411

In Marshall County, about 3 in 10 reported tests over the 2008 to 2017 laboratory totals (81 of 254) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 3.8 points lower. Across 55 West Virginia counties pooled together, 37.5% of tests reached that level, so Marshall County runs 5.6 points below its state.

Of 6 neighbours with a figure, all 6 reported a larger share at or above 4 pCi/L; the spread is 35.2% (Wetzel County) to 58.3% (Monroe County, OH). By share, Marshall County is 15th of 27 West Virginia counties with 30 or more tests for the same period.

Half the tests came in under 2.5 pCi/L and half over it; the single highest reached 62.8 pCi/L. Below the action level, 93 tests (36.6%) came in under 2 pCi/L, against 37.7% statewide, and 80 tests (31.5%) fell between 2 and 4, against 24.7% statewide.

Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 31.9% share point the same way here. USGS geology rates 97% of the county's land moderate radon potential. CDC also counts 20 tests taken after mitigation in Marshall County for the same period: tests in homes where a fix was already in.

CDC's ten-year totals for Marshall County went from 264 tests (2005 to 2014) to 254 (2008 to 2017), the share going from 32.6% to 31.9%.

Marshall County against West Virginia, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Marshall County
Marshall County25431.9%2.5 pCi/LThis county
West Virginia, pooled55 counties, pooled10,06137.5%Not pooled+5.6 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+3.8 points
Morgan Countyhighest in the state24158.1%5.8 pCi/L+26.2 points
Grant Countylowest in the state1649.8%1.1 pCi/L−22.1 points
Monroe County, OHborders it4858.3%5.0 pCi/L+26.4 points
Belmont County, OHborders it69745.2%3.6 pCi/L+13.3 points
Ohio County, WVborders it85340.3%3.2 pCi/L+8.4 points
Greene County, PAborders it15439.0%3.3 pCi/L+7.1 points
Washington County, PAborders it2,68237.9%3.0 pCi/L+6.0 points
Wetzel County, WVborders it5435.2%2.7 pCi/L+3.3 points
Where Marshall County's reported results fell, 2008 to 2017, laboratory, beside West Virginia and the United States
ResultMarshall County testsMarshall County shareWest Virginia shareU.S. shareAgainst West Virginia
Under 2 pCi/L9336.6%37.7%39.6%−1.1 points
2 to 4 pCi/L8031.5%24.7%24.7%+6.8 points
4 pCi/L and above8131.9%37.5%35.7%−5.6 points
Marshall County ranked among the 27 West Virginia counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Preston County10 of 2717636.9%2.5 pCi/L
Harrison County11 of 2718736.4%2.6 pCi/L
Randolph County11 of 273336.4%2.5 pCi/L
Wetzel County13 of 275435.2%2.7 pCi/L
Mercer County14 of 2710133.7%2.1 pCi/L
Marshall County15 of 2725431.9%2.5 pCi/L
Pendleton County16 of 275530.9%2.5 pCi/L
Marion County17 of 2724429.1%2.6 pCi/L
Taylor County18 of 273228.1%2.2 pCi/L
Putnam County19 of 275223.1%1.5 pCi/L
Tyler County20 of 273522.9%1.8 pCi/L
Marshall County ten-year laboratory totals, against West Virginia's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestWest Virginia, pooledChange from the row before
2008 to 201725431.9%2.5 pCi/L62.8 pCi/L37.5%−0.4 points
2007 to 201628832.3%2.5 pCi/L62.8 pCi/L37.3%−1.3 points
2006 to 201526833.6%2.6 pCi/L62.8 pCi/L37.7%+1.0 points
2005 to 201426432.6%2.6 pCi/L62.8 pCi/L37.3%First on file

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

Marshall County, Geology

The ground under Marshall County

Predicted

Most of the ground under Marshall County is one class on USGS's geologic map: 96.8% of its land is moderate radon potential, with 3.2% high. 96.2% of it lies in the area the map calls Central Allegheny Plateau, to which USGS gives a radon index of 10, in the moderate band (9 to 11).

USGS's geologic areas under Marshall County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Central Allegheny PlateauPermian and Pennsylvanian shale, siltstone, sandstone, minor limestone.Moderate1096.2%
Pennsylvanian Rocks of the Pittsburgh Low PlateauPennsylvanian marine shale, siltstone, sandstone, limestone, and coal.High143.1%

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

Marshall County beside the ground around it

West Virginia as a whole has more high-potential ground than Marshall County: 18.7% of its land, against 3.2% here. Of the 6 counties that border it, 4 have more high-potential ground, Belmont County, OH the most at 69.1%.

Share of land by USGS radon potential: Marshall County, the 6 counties bordering it and West Virginia
AreaEPA zoneLow potentialModerate potentialHigh potential
Marshall CountyZone 1None96.8%3.2%
Ohio CountyZone 1None69.7%30.3%
Belmont County, OHZone 1None30.9%69.1%
Wetzel CountyZone 1None100%None
Greene County, PAZone 2None92.3%7.7%
Monroe County, OHZone 2None100%None
Washington County, PAZone 2None58.8%41.2%
West Virginia55 counties, pooled by land areaVaries14.0%67.3%18.7%

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

Local help

Marshall County, Local resources

Radon testing and mitigation in Marshall County

Listed radon businesses with an address in Marshall County:

Listed radon professionals by town: Wheeling, Glen Dale

What West Virginia's program says
Phone
304-352-5039
Email
Radon@wv.gov
Licensing of radon professionals
Complete listings of professionals licensed to perform Asbestos, Lead, Radon and Clandestine Drug Laboratory Remediation activities in West Virginia.

What it means

Marshall County, Questions

Questions about radon in Marshall County

Are radon levels high in Marshall County?

Over the 2008 to 2017 laboratory totals, 31.9% of the radon tests reported to CDC for Marshall County, West Virginia were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.5 pCi/L. Of 27 West Virginia counties with 30 or more tests for the same period, 14 reported a higher share; pooled, the state comes to 37.5%.

Which counties border Marshall County?

Marshall County borders 6 counties: Ohio County, WV, Belmont County, OH, Wetzel County, WV, Greene County, PA, Monroe County, OH and Washington County, PA.

Products

Marshall County, Products

Testing a home in Marshall County

In Marshall County, 31.9% of 254 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 37.5% pooled across West Virginia. In Zone 1 the year-round level in Marshall 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

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

Explore

Marshall County, Bordering counties

Counties bordering Marshall County

Calculated by Radon411

Marshall County, Cities and towns

Cities and towns in Marshall County

About 29,159 people live in Marshall County by the Census Bureau's estimate for July 1, 2025, 1,339 fewer than in 2020 (−4.4%). That works out to 95 people per square mile of land. Wheeling, the largest place on its list (25,680 residents in all), extends beyond Marshall County, so no share of the total is worked out for it. Testing is reported here more often than across the state: CDC's 254 reported tests for 2008 to 2017 come to 8.7 for every 1,000 residents (2025 estimate), against 5.7 for West Virginia.

From Wheeling to Cameron, CDC publishes no figure by town: each reads Marshall County's.

The cities and towns in Marshall County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Wheelingextends beyond Marshall County25,680−4.7%Counted whole
Moundsville7,659−5.1%26.3%
McMechen1,605−4.9%5.5%
Glen Dale1,404−5.0%4.8%
Benwood1,196−5.7%4.1%
Cameron818−5.3%2.8%

6 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 Marshall County is counted whole, so it has no share.

Marshall County, Homes

Homes in Marshall County

Marshall County is a place of houses on their own lots: 82% of its 14,736 homes are detached single-family houses, against 71% across West Virginia. The homes are older than West Virginia's as a whole: half were built before 1960 (1976 for West Virginia), and 50% date from before 1960. Owners live in 79% of the occupied homes (West Virginia: 74%), so for most households a test and a fix are their own to order.

Homes in Marshall County, West Virginia, 2019 to 2023
HomesMarshall CountyWest Virginia
Housing units14,736859,653
Detached houses82%71%
In buildings of 5 or more3%8%
Mobile homes8%14%
Built before 196050%33%
Built since 20008%18%
Middle year built19601976
Owner-occupied79%74%

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