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Radon Levels in Rockbridge County, Virginia

EPA puts Rockbridge County in Zone 1, its highest radon zone, and high results are common there: 50.9% of the 114 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

    50.9%

    20.5 pts above VA

    Rockbridge
    50.9%
    Virginia
    30.4%

    114 tests, 2008 to 2017

  • Median result

    4.0pCi/L

    Action level reached

    Rockbridge
    4.0 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    114

    57th of 84 by tests

    Rockbridge
    114
    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

    10 of 84

    Top quarter

    Rockbridge
    50.9%
    Russell
    67.3%

    By share, of 84 with 30+ tests

Read a result for Rockbridge County

Starts at Rockbridge County's median, 4.0 pCi/L

4.0pCi/L

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

EPA’s reading of 4.0 pCi/L

At or above 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 at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. Rockbridge County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Rockbridge County, At a glance

Rockbridge County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Rockbridge 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 94% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

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

Reported results by concentration band, Rockbridge County, 2008 to 2017, laboratory
Under 2 pCi/L: 25%2 to 4 pCi/L: 24%4 pCi/L and above: 51%

Of 114 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Rockbridge County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L2925.4%
2 to 4 pCi/L2723.7%
4 pCi/L and above5850.9%
What these figures count

These are the 114 tests reported to CDC for Rockbridge 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

Rockbridge County, Compared

Rockbridge County radon figures, compared

Calculated by Radon411

More than half: 50.9% of the 114 radon tests reported to CDC for Rockbridge County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 10th of 84 Virginia counties with 30 or more tests for the same period. That is 20.5 points above the 30.4% pooled from 131 Virginia counties.

The median result, 4.0 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 42.3 pCi/L. The rest split 25.4% under 2 pCi/L and 23.7% from 2 to 4 (Virginia: 44.7% and 24.9%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 50.9% share point the same way here.

No bordering county with a figure for the same period reported a higher share; the closest is Augusta County at 50.1%, the lowest Lexington city at 18.8%. Statewide for the same period, Russell County reported the highest share (67.3%) and Norfolk city the lowest (2.7%).

CDC's ten-year totals for Rockbridge County went from 100 tests (2005 to 2014) to 114 (2008 to 2017), the share going from 49.0% to 50.9%.

Nationally, every county with a figure for the same period pools to 35.7%; Rockbridge County sits 15.2 points above it. CDC also counts 18 tests taken after mitigation in Rockbridge County for the same period: tests in homes where a fix was already in.

Rockbridge County against Virginia, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Rockbridge County
Rockbridge County11450.9%4.0 pCi/LThis county
Virginia, pooled131 counties, pooled53,19930.4%Not pooled−20.5 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−15.2 points
Russell Countyhighest in the state4967.3%6.7 pCi/L+16.4 points
Norfolk citylowest in the state732.7%0.5 pCi/L−48.2 points
Buena Vista city, VAborders it785.7%10.4 pCi/L+34.8 points
Augusta County, VAborders it62550.1%4.0 pCi/L−0.8 points
Botetourt County, VAborders it57542.1%3.3 pCi/L−8.8 points
Alleghany County, VAborders it5040.0%3.0 pCi/L−10.9 points
Amherst County, VAborders it24736.8%2.9 pCi/L−14.1 points
Nelson County, VAborders it12228.7%2.6 pCi/L−22.2 points
Bedford County, VAborders it74923.5%2.1 pCi/L−27.4 points
Lexington city, VAborders it3218.8%1.6 pCi/L−32.1 points
Bath County, VAborders it2218.2%2.3 pCi/L−32.7 points
Where Rockbridge County's reported results fell, 2008 to 2017, laboratory, beside Virginia and the United States
ResultRockbridge County testsRockbridge County shareVirginia shareU.S. shareAgainst Virginia
Under 2 pCi/L2925.4%44.7%39.6%−19.3 points
2 to 4 pCi/L2723.7%24.9%24.7%−1.2 points
4 pCi/L and above5850.9%30.4%35.7%+20.5 points
Rockbridge 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
Washington County5 of 8438458.1%4.8 pCi/L
Giles County6 of 8417456.9%4.8 pCi/L
Patrick County7 of 845354.7%5.3 pCi/L
Staunton city8 of 8433852.7%4.2 pCi/L
Bristol city9 of 8411050.9%4.2 pCi/L
Rockbridge County10 of 8411450.9%4.0 pCi/L
Scott County11 of 847550.7%4.0 pCi/L
Augusta County12 of 8462550.1%4.0 pCi/L
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
Rockbridge County ten-year laboratory totals, against Virginia's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestVirginia, pooledChange from the row before
2008 to 201711450.9%4.0 pCi/L42.3 pCi/L30.4%−0.9 points
2007 to 201611451.8%4.5 pCi/L42.3 pCi/L30.6%+0.9 points
2006 to 201511250.9%4.3 pCi/L42.3 pCi/L30.7%+1.9 points
2005 to 201410049.0%3.7 pCi/L39.8 pCi/L30.3%First on file

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

Rockbridge County, Geology

The ground under Rockbridge County

Predicted

Most of the ground under Rockbridge County is one class on USGS's geologic map: 93.8% of its land is high radon potential, with 6.2% moderate. The map puts 93.8% of Rockbridge County in the area it calls Valley and Ridge and 6.2% in Blue Ridge. USGS gives the first a radon index of 15, in the high band (12 to 17), and the second 10, in the moderate band (9 to 11).

USGS's geologic areas under Rockbridge 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.High1593.8%
Blue RidgeGranite, pegmatite, monazite, schist, and gneiss.Moderate106.2%

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

Rockbridge County beside the ground around it

Rockbridge County has more high-potential ground than Virginia as a whole: 93.8% of its land against 47.9%. Of the 9 counties that border it, 5 have more high-potential ground, Bath County the most at 100%.

Share of land by USGS radon potential: Rockbridge County, the 9 counties bordering it and Virginia
AreaEPA zoneLow potentialModerate potentialHigh potential
Rockbridge CountyZone 1None6.2%93.8%
Lexington cityZone 1NoneNone100%
Buena Vista cityZone 1NoneNone100%
Amherst CountyZone 2None82.8%17.2%
Bath CountyZone 1NoneNone100%
Botetourt CountyZone 1None6.5%93.5%
Augusta CountyZone 1None4.9%95.1%
Nelson CountyZone 2None77.8%22.2%
Bedford CountyZone 2None84.9%15.1%
Alleghany CountyZone 1NoneNone100%
Virginia133 counties, pooled by land areaVaries20.6%30.0%47.9%

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

Local help

Rockbridge County, Local resources

Radon testing and mitigation in Rockbridge 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

Rockbridge County, Questions

Questions about radon in Rockbridge County

Are radon levels high in Rockbridge County?

Over the 2008 to 2017 laboratory totals, 50.9% of the radon tests reported to CDC for Rockbridge County, Virginia were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.0 pCi/L. Of 84 Virginia counties with 30 or more tests for the same period, 9 reported a higher share; pooled, the state comes to 30.4%.

Which counties border Rockbridge County?

Rockbridge County borders 9 counties: Lexington city, Buena Vista city, Amherst County, Bath County, Botetourt County, Augusta County, Nelson County, Bedford County and Alleghany County.

Products

Rockbridge County, Products

Testing a home in Rockbridge County

In Rockbridge County, 50.9% of 114 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 Rockbridge 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

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

Explore

Rockbridge County, Bordering counties

Counties bordering Rockbridge County

Calculated by Radon411

Rockbridge County, Cities and towns

Cities and towns in Rockbridge County

Rockbridge County's population has barely moved since 2020: 22,663 residents on July 1, 2025 against 22,668 then, by the Census Bureau's estimates. That works out to 38 people per square mile of land. No town dominates: Glasgow, the largest, has 1,049 residents, 4.6% of the total. Together its 2 incorporated places hold 6.1% of those residents; the other 93.9% live outside any of them. CDC's 114 reported tests for 2008 to 2017 work out to 5.0 per 1,000 residents (2025 estimate), close to Virginia's 6.0.

From Glasgow to Goshen, CDC publishes no figure by town: each reads Rockbridge County's.

The cities and towns in Rockbridge County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Glasgow1,049−0.6%4.6%
Goshen340+0.3%1.5%

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).

Rockbridge County, Homes

Homes in Rockbridge County

Rockbridge County is a place of houses on their own lots: 80% of its 11,315 homes are detached single-family houses, against 61% across Virginia. Half of its homes were built before 1980, close to Virginia's 1984: 27% date from before 1960 and 22% from 2000 or later. Owners live in 78% of the occupied homes (Virginia: 67%), so for most households a test and a fix are their own to order.

Homes in Rockbridge County, Virginia, 2019 to 2023
HomesRockbridge CountyVirginia
Housing units11,3153,654,784
Detached houses80%61%
In buildings of 5 or more5%19%
Mobile homes10%4%
Built before 196027%19%
Built since 200022%25%
Middle year built19801984
Owner-occupied78%67%

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