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Radon Levels in Mercer County, West Virginia

EPA puts Mercer County in Zone 1, its highest radon zone, and 33.7% of its 101 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

    33.7%

    3.8 pts below WV

    Mercer
    33.7%
    WV
    37.5%

    101 tests, 2008 to 2017

  • Median result

    2.1pCi/L

    Below action level

    Mercer
    2.1 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    101

    18th of 27 by tests

    Mercer
    101
    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

    14 of 27

    Middle half

    Mercer
    33.7%
    Morgan
    58.1%

    By share, of 27 with 30+ tests

Read a result for Mercer County

Starts at Mercer County's median, 2.1 pCi/L

2.1pCi/L

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

EPA’s reading of 2.1 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. Mercer County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Mercer County, At a glance

Mercer County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Mercer 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 73% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

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

Reported results by concentration band, Mercer County, 2008 to 2017, laboratory
Under 2 pCi/L: 48%2 to 4 pCi/L: 18%4 pCi/L and above: 34%

Of 101 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Mercer County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L4948.5%
2 to 4 pCi/L1817.8%
4 pCi/L and above3433.7%
What these figures count

These are the 101 tests reported to CDC for Mercer 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

Mercer County, Compared

Mercer County radon figures, compared

Calculated by Radon411

In Mercer County, about 3 in 10 reported tests over the 2008 to 2017 laboratory totals (34 of 101) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 2.0 points lower. Across 55 West Virginia counties pooled together, 37.5% of tests reached that level, so Mercer County runs 3.8 points below its state.

Of 3 neighbours with a figure, 2 reported a larger share at or above 4 pCi/L and 1 a smaller one; the spread is 16.7% (Raleigh County) to 56.9% (Giles County, VA). By share, Mercer County is 14th of 27 West Virginia counties with 30 or more tests for the same period.

Half the tests came in under 2.1 pCi/L and half over it; the single highest reached 28.5 pCi/L. Below the action level, 49 tests (48.5%) came in under 2 pCi/L, against 37.7% statewide, and 18 tests (17.8%) fell between 2 and 4, against 24.7% statewide.

Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 33.7% share point the same way here. USGS geology rates 73% of the county's land moderate radon potential.

CDC's ten-year totals for Mercer County went from 47 tests (2005 to 2014) to 101 (2008 to 2017), the share going from 31.9% to 33.7%.

Mercer County against West Virginia, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Mercer County
Mercer County10133.7%2.1 pCi/LThis county
West Virginia, pooled55 counties, pooled10,06137.5%Not pooled+3.8 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+2.0 points
Morgan Countyhighest in the state24158.1%5.8 pCi/L+24.4 points
Grant Countylowest in the state1649.8%1.1 pCi/L−23.9 points
Giles County, VAborders it17456.9%4.8 pCi/L+23.2 points
Bland County, VAborders it1346.2%2.6 pCi/L+12.5 points
Tazewell County, VAborders it37240.3%2.8 pCi/L+6.6 points
Wyoming County, WVborders it333.3%0.8 pCi/L−0.4 points
Raleigh County, WVborders it4216.7%1.4 pCi/L−17.0 points
Summers County, WVborders it1513.3%1.5 pCi/L−20.4 points
McDowell County, WVborders it30.0%2.5 pCi/L−33.7 points
Where Mercer County's reported results fell, 2008 to 2017, laboratory, beside West Virginia and the United States
ResultMercer County testsMercer County shareWest Virginia shareU.S. shareAgainst West Virginia
Under 2 pCi/L4948.5%37.7%39.6%+10.8 points
2 to 4 pCi/L1817.8%24.7%24.7%−6.9 points
4 pCi/L and above3433.7%37.5%35.7%−3.8 points
Mercer 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
Hampshire County9 of 279038.9%2.8 pCi/L
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
Mercer 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 201710133.7%2.1 pCi/L28.5 pCi/L37.5%+0.8 points
2007 to 20167632.9%2.0 pCi/L28.5 pCi/L37.3%+1.4 points
2006 to 20155431.5%2.2 pCi/L28.5 pCi/L37.7%−0.4 points
2005 to 20144731.9%1.9 pCi/L28.5 pCi/L37.3%First on file

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

Mercer County, Geology

The ground under Mercer County

Predicted

USGS's geologic map splits Mercer County: 72.6% of its land is moderate radon potential and 16.0% high and 11.4% low. The map puts 72.6% of Mercer County in the area it calls Southern Appalachian Valley and Ridge and 15.8% in Northern Appalachian Valley and Ridge, with one smaller area beside them. USGS gives the first a radon index of 11, in the moderate band (9 to 11), and the second 14, in the high band (12 to 17).

USGS's geologic areas under Mercer County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Southern Appalachian Valley and RidgeOrdovician-Mississippian shale, siltstone, sandstone, limestone.Moderate1172.6%
Northern Appalachian Valley and RidgeSandstone ridges, shale and limestone valleys, mostly DevonianHigh1415.8%
Cumberland PlateauPennsylvanian sandstone, siltstone, shale, and coalLow811.4%

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

Mercer County beside the ground around it

On high-potential ground Mercer County is close to West Virginia as a whole: 16.0% of its land against 18.7%. Of the 7 counties that border it, 3 have more high-potential ground, Bland County, VA the most at 100%.

Share of land by USGS radon potential: Mercer County, the 7 counties bordering it and West Virginia
AreaEPA zoneLow potentialModerate potentialHigh potential
Mercer CountyZone 111.4%72.6%16.0%
Bland County, VAZone 1NoneNone100%
Summers CountyZone 1None100%None
Giles County, VAZone 1NoneNone100%
Raleigh CountyZone 243.4%56.6%None
McDowell CountyZone 398.3%1.3%0.3%
Wyoming CountyZone 3100%NoneNone
Tazewell County, VAZone 10.1%24.8%75.1%
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

Mercer County, Local resources

Radon testing and mitigation in Mercer County

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

Mercer County, Questions

Questions about radon in Mercer County

Are radon levels high in Mercer County?

Over the 2008 to 2017 laboratory totals, 33.7% of the radon tests reported to CDC for Mercer County, West Virginia were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.1 pCi/L. Of 27 West Virginia counties with 30 or more tests for the same period, 13 reported a higher share; pooled, the state comes to 37.5%.

Which counties border Mercer County?

Mercer County borders 7 counties: Bland County, VA, Summers County, WV, Giles County, VA, Raleigh County, WV, McDowell County, WV, Wyoming County, WV and Tazewell County, VA.

Products

Mercer County, Products

Testing a home in Mercer County

In Mercer County, 33.7% of 101 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 Mercer 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

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

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Mercer County, Bordering counties

Counties bordering Mercer County

Calculated by Radon411

Mercer County, Cities and towns

Cities and towns in Mercer County

About 57,503 people live in Mercer County by the Census Bureau's estimate for July 1, 2025, 2,025 fewer than in 2020 (−3.4%). That works out to 137 people per square mile of land. No town dominates: Bluefield, the largest, has 9,158 residents, 15.9% of the total. Reported testing is thin here: 101 tests over 2008 to 2017, or 1.8 for every 1,000 residents (2025 estimate), where West Virginia as a whole comes to 5.7.

From Bluefield to Matoaka, CDC publishes no figure by town: each reads Mercer County's.

The 5 largest cities and towns in Mercer County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Bluefield9,158−4.8%15.9%
Princeton5,578−4.7%9.7%
Athens1,184−3.0%2.1%
Bramwell259−4.4%0.5%
Oakvale132−0.8%0.2%
  • Matoaka

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).

Mercer County, Homes

Homes in Mercer County

Of Mercer County's 29,358 homes, 67% are detached houses, against 71% across West Virginia; 20% are mobile homes. Half of its homes were built before 1974, close to West Virginia's 1976: 32% date from before 1960 and 14% from 2000 or later. 70% of occupied homes are lived in by their owner (West Virginia: 74%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Mercer County, West Virginia, 2019 to 2023
HomesMercer CountyWest Virginia
Housing units29,358859,653
Detached houses67%71%
In buildings of 5 or more8%8%
Mobile homes20%14%
Built before 196032%33%
Built since 200014%18%
Middle year built19741976
Owner-occupied70%74%

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