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Radon Levels in Alleghany County, Virginia

EPA puts Alleghany County in Zone 1, its highest radon zone, and high results are common there: 40.0% of the 50 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

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  • Share at 4+ pCi/L

    40.0%

    9.6 pts above VA

    Alleghany
    40.0%
    Virginia
    30.4%

    50 tests, 2008 to 2017

  • Median result

    3.0pCi/L

    Below action level

    Alleghany
    3.0 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    50

    72nd of 84 by tests

    Alleghany
    50
    Fairfax
    8,657

    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 Virginia

    28 of 84

    Middle half

    Alleghany
    40.0%
    Russell
    67.3%

    By share, of 84 with 30+ tests

Read a result for Alleghany County

Starts at Alleghany County's median, 3.0 pCi/L

3.0pCi/L

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

EPA’s reading of 3.0 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. Alleghany County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Alleghany County, At a glance

Alleghany County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

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

Reported results by concentration band, Alleghany County, 2008 to 2017, laboratory
Under 2 pCi/L: 28%2 to 4 pCi/L: 32%4 pCi/L and above: 40%

Of 50 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Alleghany County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L1428.0%
2 to 4 pCi/L1632.0%
4 pCi/L and above2040.0%
What these figures count

These are the 50 tests reported to CDC for Alleghany 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

Alleghany County, Compared

Alleghany County radon figures, compared

Calculated by Radon411

In Alleghany County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (20 of 50) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 4.3 points higher. Across 131 Virginia counties pooled together, 30.4% of tests reached that level, so Alleghany County runs 9.6 points above its state.

Of 3 neighbours with a figure, all 3 reported a larger share at or above 4 pCi/L; the spread is 42.1% (Botetourt County) to 52.3% (Greenbrier County, WV). By share, Alleghany County is 28th of 84 Virginia counties with 30 or more tests for the same period.

Half the tests came in under 3.0 pCi/L and half over it; the single highest reached 23.8 pCi/L. Below the action level, 14 tests (28.0%) came in under 2 pCi/L, against 44.7% statewide, and 16 tests (32.0%) fell between 2 and 4, against 24.9% statewide.

Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 40.0% share point the same way here. USGS geology rates 100% of the county's land high radon potential. CDC also counts 6 tests taken after mitigation in Alleghany County for the same period: tests in homes where a fix was already in.

CDC's ten-year totals for Alleghany County went from 51 tests (2005 to 2014) to 50 (2008 to 2017), the share going from 45.1% to 40.0%.

Alleghany County against Virginia, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Alleghany County
Alleghany County5040.0%3.0 pCi/LThis county
Virginia, pooled131 counties, pooled53,19930.4%Not pooled−9.6 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−4.3 points
Russell Countyhighest in the state4967.3%6.7 pCi/L+27.3 points
Norfolk citylowest in the state732.7%0.5 pCi/L−37.3 points
Greenbrier County, WVborders it17652.3%4.5 pCi/L+12.3 points
Rockbridge County, VAborders it11450.9%4.0 pCi/L+10.9 points
Craig County, VAborders it1346.2%2.8 pCi/L+6.2 points
Botetourt County, VAborders it57542.1%3.3 pCi/L+2.1 points
Covington city, VAborders it540.0%3.3 pCi/LLevel
Monroe County, WVborders it1833.3%3.6 pCi/L−6.7 points
Bath County, VAborders it2218.2%2.3 pCi/L−21.8 points
Where Alleghany County's reported results fell, 2008 to 2017, laboratory, beside Virginia and the United States
ResultAlleghany County testsAlleghany County shareVirginia shareU.S. shareAgainst Virginia
Under 2 pCi/L1428.0%44.7%39.6%−16.7 points
2 to 4 pCi/L1632.0%24.9%24.7%+7.1 points
4 pCi/L and above2040.0%30.4%35.7%+9.6 points
Alleghany County ranked among the 84 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
Botetourt County23 of 8457542.1%3.3 pCi/L
Radford city24 of 849841.8%3.2 pCi/L
Rappahannock County25 of 8413741.6%3.3 pCi/L
Tazewell County26 of 8437240.3%2.8 pCi/L
Culpeper County27 of 8489140.1%3.2 pCi/L
Alleghany County28 of 845040.0%3.0 pCi/L
Prince Edward County28 of 845040.0%2.5 pCi/L
Campbell County30 of 8436539.7%3.2 pCi/L
Brunswick County31 of 843839.5%2.8 pCi/L
Pittsylvania County32 of 8424238.4%3.0 pCi/L
Page County33 of 8414138.3%3.3 pCi/L
Alleghany County ten-year laboratory totals, against Virginia's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestVirginia, pooledChange from the row before
2008 to 20175040.0%3.0 pCi/L23.8 pCi/L30.4%−1.2 points
2007 to 20165141.2%3.4 pCi/L23.8 pCi/L30.6%−3.2 points
2006 to 20155444.4%3.5 pCi/L23.8 pCi/L30.7%−0.7 points
2005 to 20145145.1%3.6 pCi/L23.8 pCi/L30.3%First on file

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

Alleghany County, Geology

The ground under Alleghany County

Predicted

USGS's geologic map puts all of Alleghany County's mapped land in one class: high radon potential. All of it lies in the area the map calls Valley and Ridge, to which USGS gives a radon index of 15, in the high band (12 to 17).

USGS's geologic areas under Alleghany County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Valley and RidgeCambrian dolomite, limestone, shale, and sandstone, Silurian-Ordovician limestone, dolomite, shale, and sandstone, Mississippian-Devonian sandstone, shale, limestone, gypsum, and coal.High1599.9%

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

Alleghany County beside the ground around it

Alleghany County has more high-potential ground than Virginia as a whole: 100% of its land against 47.9%. Of the 7 counties that border it, none has as large a share of high-potential ground; Bath County comes nearest at 100%.

Share of land by USGS radon potential: Alleghany County, the 7 counties bordering it and Virginia
AreaEPA zoneLow potentialModerate potentialHigh potential
Alleghany CountyZone 1NoneNone100%
Covington cityZone 1NoneNone100%
Greenbrier County, WVZone 1None76.5%23.5%
Craig CountyZone 1NoneNone100%
Botetourt CountyZone 1None6.5%93.5%
Bath CountyZone 1NoneNone100%
Monroe County, WVZone 1None54.8%45.2%
Rockbridge CountyZone 1None6.2%93.8%
Virginia133 counties, pooled by land areaVaries20.6%30.0%47.9%

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

Local help

Alleghany County, Local resources

Radon testing and mitigation in Alleghany County

What Virginia's program says
Phone
(804) 864-8161
Email
Radon@vdh.virginia.gov
Licensing of radon professionals
The Code of Virginia requires that Radon testers and mitigators be currently certified by either the National Radon Proficiency Program (NRPP) or the National Radon Safety Board (NRSB).

What it means

Alleghany County, Questions

Questions about radon in Alleghany County

Are radon levels high in Alleghany County?

Over the 2008 to 2017 laboratory totals, 40.0% of the radon tests reported to CDC for Alleghany County, Virginia were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.0 pCi/L. Of 84 Virginia counties with 30 or more tests for the same period, 27 reported a higher share; pooled, the state comes to 30.4%.

Which counties border Alleghany County?

Alleghany County borders 7 counties: Covington city, VA, Greenbrier County, WV, Craig County, VA, Botetourt County, VA, Bath County, VA, Monroe County, WV and Rockbridge County, VA.

Products

Alleghany County, Products

Testing a home in Alleghany County

In Alleghany County, 40.0% of 50 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 30.4% pooled across Virginia. In Zone 1 the year-round level in Alleghany 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

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

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Alleghany County, Bordering counties

Counties bordering Alleghany County

Calculated by Radon411

Alleghany County, Cities and towns

Cities and towns in Alleghany County

About 14,546 people live in Alleghany County by the Census Bureau's estimate for July 1, 2025, 641 fewer than in 2020 (−4.2%). That works out to 33 people per square mile of land. Its largest town, Clifton Forge, has 3,372 residents, 23.2% of the total. Together its 2 incorporated places hold 25.3% of those residents; the other 74.7% live outside any of them. Reported testing is thin here: 50 tests over 2008 to 2017, or 3.4 for every 1,000 residents (2025 estimate), where Virginia as a whole comes to 6.0.

From Clifton Forge to Iron Gate, CDC publishes no figure by town: each reads Alleghany County's.

The cities and towns in Alleghany County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Clifton Forge3,372−4.7%23.2%
Iron Gate305−4.7%2.1%

2 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).

Alleghany County, Homes

Homes in Alleghany County

Alleghany County is a place of houses on their own lots: 77% of its 7,916 homes are detached single-family houses, against 61% across Virginia. The homes are older than Virginia's as a whole: half were built before 1969 (1984 for Virginia), and 39% date from before 1960. Owners live in 81% of the occupied homes (Virginia: 67%), so for most households a test and a fix are their own to order.

Homes in Alleghany County, Virginia, 2019 to 2023
HomesAlleghany CountyVirginia
Housing units7,9163,654,784
Detached houses77%61%
In buildings of 5 or more8%19%
Mobile homes12%4%
Built before 196039%19%
Built since 20009%25%
Middle year built19691984
Owner-occupied81%67%

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