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Radon Levels in Grayson County, Virginia

EPA puts Grayson County in Zone 2, its middle radon zone, and high results are common there: 44.7% of the 47 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

    44.7%

    14.3 pts above VA

    Grayson
    44.7%
    Virginia
    30.4%

    47 tests, 2008 to 2017

  • Median result

    3.8pCi/L

    Below action level

    Grayson
    3.8 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    47

    77th of 84 by tests

    Grayson
    47
    Fairfax
    8,657

    Reported to CDC before any fix, 2008 to 2017

  • EPA radon zone

    Zone 2

    Moderate potential

    1. 1
    2. Zone 2
    3. 3

    1 highest, 3 lowest

    EPA predicts 2 to 4 pCi/L indoors

  • Rank in Virginia

    18 of 84

    Top quarter

    Grayson
    44.7%
    Russell
    67.3%

    By share, of 84 with 30+ tests

Read a result for Grayson County

Starts at Grayson County's median, 3.8 pCi/L

3.8pCi/L

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

EPA’s reading of 3.8 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. Grayson County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Grayson County, At a glance

Grayson County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Grayson County is a county: EPA's forecast for it as a whole is an average indoor of 2 to 4 pCi/L (75 to 150 Bq/m³). It describes no single address, and homes above EPA's are found in every zone, this one included.

USGS geologic potential: Moderate across 98% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

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

Reported results by concentration band, Grayson County, 2008 to 2017, laboratory
Under 2 pCi/L: 32%2 to 4 pCi/L: 23%4 pCi/L and above: 45%

Of 47 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Grayson County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L1531.9%
2 to 4 pCi/L1123.4%
4 pCi/L and above2144.7%
What these figures count

These are the 47 tests reported to CDC for Grayson 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

Grayson County, Compared

Grayson County radon figures, compared

Calculated by Radon411

In Grayson County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (21 of 47) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 9.0 points higher. Across 131 Virginia counties pooled together, 30.4% of tests reached that level, so Grayson County runs 14.3 points above its state.

Of 8 neighbours with a figure, 4 reported a larger share at or above 4 pCi/L and 4 a smaller one; the spread is 33.3% (Surry County, NC) to 65.5% (Wythe County). By share, Grayson County is 18th of 84 Virginia counties with 30 or more tests for the same period.

Half the tests came in under 3.8 pCi/L and half over it; the single highest reached 34.1 pCi/L. Below the action level, 15 tests (31.9%) came in under 2 pCi/L, against 44.7% statewide, and 11 tests (23.4%) fell between 2 and 4, against 24.9% statewide.

Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 44.7% share point the same way here. USGS geology rates 98% of the county's land moderate radon potential.

CDC's ten-year totals for Grayson County went from 46 tests (2005 to 2014) to 47 (2008 to 2017), the share going from 47.8% to 44.7%.

Grayson County against Virginia, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Grayson County
Grayson County4744.7%3.8 pCi/LThis county
Virginia, pooled131 counties, pooled53,19930.4%Not pooled−14.3 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−9.0 points
Russell Countyhighest in the state4967.3%6.7 pCi/L+22.6 points
Norfolk citylowest in the state732.7%0.5 pCi/L−42.0 points
Wythe County, VAborders it11965.5%6.0 pCi/L+20.8 points
Carroll County, VAborders it8961.8%5.0 pCi/L+17.1 points
Smyth County, VAborders it12361.0%5.5 pCi/L+16.3 points
Washington County, VAborders it38458.1%4.8 pCi/L+13.4 points
Alleghany County, NCborders it28541.1%3.3 pCi/L−3.6 points
Galax city, VAborders it1838.9%3.3 pCi/L−5.8 points
Johnson County, TNborders it15734.4%2.3 pCi/L−10.3 points
Ashe County, NCborders it68134.1%2.5 pCi/L−10.6 points
Surry County, NCborders it85533.3%2.4 pCi/L−11.4 points
Where Grayson County's reported results fell, 2008 to 2017, laboratory, beside Virginia and the United States
ResultGrayson County testsGrayson County shareVirginia shareU.S. shareAgainst Virginia
Under 2 pCi/L1531.9%44.7%39.6%−12.8 points
2 to 4 pCi/L1123.4%24.9%24.7%−1.5 points
4 pCi/L and above2144.7%30.4%35.7%+14.3 points
Grayson 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
Pulaski County13 of 8426849.6%3.9 pCi/L
Waynesboro city14 of 8419648.5%3.8 pCi/L
Clarke County15 of 8435047.7%3.5 pCi/L
King George County16 of 8448845.5%3.6 pCi/L
Winchester city17 of 8477344.8%3.3 pCi/L
Grayson County18 of 844744.7%3.8 pCi/L
Frederick County19 of 842,45144.1%3.3 pCi/L
Madison County20 of 8418444.0%3.5 pCi/L
Rockingham County21 of 841,71443.9%3.3 pCi/L
Floyd County22 of 845442.6%3.3 pCi/L
Botetourt County23 of 8457542.1%3.3 pCi/L
Grayson County ten-year laboratory totals, against Virginia's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestVirginia, pooledChange from the row before
2008 to 20174744.7%3.8 pCi/L34.1 pCi/L30.4%−4.2 points
2007 to 20164748.9%3.9 pCi/L34.1 pCi/L30.6%Level
2006 to 20154748.9%3.9 pCi/L34.1 pCi/L30.7%+1.1 points
2005 to 20144647.8%3.8 pCi/L34.1 pCi/L30.3%First on file

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

Grayson County, Geology

The ground under Grayson County

Predicted

Most of the ground under Grayson County is one class on USGS's geologic map: 97.5% of its land is moderate radon potential, with 2.5% high. 97.5% of it lies in the area the map calls Blue Ridge, to which USGS gives a radon index of 10, in the moderate band (9 to 11).

USGS's geologic areas under Grayson County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Blue RidgeGranite, pegmatite, monazite, schist, and gneiss.Moderate1097.5%
Valley and RidgeCambrian dolomite, limestone, shale, and sandstone, Silurian-Ordovician limestone, dolomite, shale, and sandstone, Mississippian-Devonian sandstone, shale, limestone, gypsum, and coal.High152.5%

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

Grayson County beside the ground around it

Virginia as a whole has more high-potential ground than Grayson County: 47.9% of its land, against 2.5% here. Of the 9 counties that border it, 5 have more high-potential ground, Wythe County the most at 99.8%.

Share of land by USGS radon potential: Grayson County, the 9 counties bordering it and Virginia
AreaEPA zoneLow potentialModerate potentialHigh potential
Grayson CountyZone 2None97.5%2.5%
Alleghany County, NCZone 1None100%None
Galax cityZone 2None100%None
Wythe CountyZone 1None0.2%99.8%
Smyth CountyZone 1None5.3%94.7%
Ashe County, NCZone 2None100%None
Carroll CountyZone 2None96.1%3.9%
Surry County, NCZone 2None100%None
Johnson County, TNZone 2None14.9%85.1%
Washington CountyZone 1None1.4%98.6%
Virginia133 counties, pooled by land areaVaries20.6%30.0%47.9%

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

Local help

Grayson County, Local resources

Radon testing and mitigation in Grayson 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

Grayson County, Questions

Questions about radon in Grayson County

Are radon levels high in Grayson County?

Over the 2008 to 2017 laboratory totals, 44.7% of the radon tests reported to CDC for Grayson County, Virginia were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.8 pCi/L. Of 84 Virginia counties with 30 or more tests for the same period, 17 reported a higher share; pooled, the state comes to 30.4%.

Which counties border Grayson County?

Grayson County borders 9 counties: Alleghany County, NC, Galax city, VA, Wythe County, VA, Smyth County, VA, Ashe County, NC, Carroll County, VA, Surry County, NC, Johnson County, TN and Washington County, VA.

Products

Grayson County, Products

Testing a home in Grayson County

In Grayson County, 44.7% of 47 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 30.4% pooled across Virginia. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Grayson County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Grayson County homes, compared

Explore

Grayson County, Bordering counties

Counties bordering Grayson County

Calculated by Radon411

Grayson County, Cities and towns

Cities and towns in Grayson County

Grayson County's population has barely moved since 2020: 15,230 residents on July 1, 2025 against 15,282 then, by the Census Bureau's estimates. That works out to 34 people per square mile of land. No town dominates: Independence, the largest, has 1,000 residents, 6.6% of the total. Together its 3 incorporated places hold 10.4% of those residents; the other 89.6% live outside any of them. Reported testing is thin here: 47 tests over 2008 to 2017, or 3.1 for every 1,000 residents (2025 estimate), where Virginia as a whole comes to 6.0.

From Independence to Troutdale, CDC publishes no figure by town: each reads Grayson County's.

The cities and towns in Grayson County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Independence1,000−0.6%6.6%
Fries444−1.1%2.9%
Troutdale138−1.4%0.9%

3 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).

Grayson County, Homes

Homes in Grayson County

Grayson County is a place of houses on their own lots: 78% of its 8,961 homes are detached single-family houses, against 61% across Virginia. The homes are older than Virginia's as a whole: half were built before 1975 (1984 for Virginia), and 33% date from before 1960. Owners live in 82% of the occupied homes (Virginia: 67%), so for most households a test and a fix are their own to order.

Homes in Grayson County, Virginia, 2019 to 2023
HomesGrayson CountyVirginia
Housing units8,9613,654,784
Detached houses78%61%
In buildings of 5 or more2%19%
Mobile homes19%4%
Built before 196033%19%
Built since 200013%25%
Middle year built19751984
Owner-occupied82%67%

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