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Radon Levels in Montgomery County, Virginia

EPA puts Montgomery County in Zone 1, its highest radon zone, and 35.5% of its 970 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

How to test this homeFind a certified tester

  • Share at 4+ pCi/L

    35.5%

    5.1 pts above VA

    Montgomery
    35.5%
    Virginia
    30.4%

    970 tests, 2008 to 2017

  • Median result

    2.5pCi/L

    Below action level

    Montgomery
    2.5 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    970

    13th of 84 by tests

    Montgomery
    970
    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

    42 of 84

    Middle half

    Montgomery
    35.5%
    Russell
    67.3%

    By share, of 84 with 30+ tests

Read a result for Montgomery County

Starts at Montgomery 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. Montgomery County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Montgomery County, At a glance

Montgomery County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Montgomery 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 87% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

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

Reported results by concentration band, Montgomery County, 2008 to 2017, laboratory
Under 2 pCi/L: 43%2 to 4 pCi/L: 22%4 pCi/L and above: 35%

Of 970 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Montgomery County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L41442.7%
2 to 4 pCi/L21221.9%
4 pCi/L and above34435.5%
What these figures count

These are the 970 tests reported to CDC for Montgomery 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

Montgomery County, Compared

Montgomery County radon figures, compared

Calculated by Radon411

In Montgomery County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (344 of 970) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 0.2 points lower. Across 131 Virginia counties pooled together, 30.4% of tests reached that level, so Montgomery County runs 5.1 points above its state.

Of 5 neighbours with a figure, 4 reported a larger share at or above 4 pCi/L and 1 a smaller one; the spread is 22.1% (Roanoke County) to 56.9% (Giles County). By share, Montgomery County is 42nd of 84 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 90.9 pCi/L. Below the action level, 414 tests (42.7%) came in under 2 pCi/L, against 44.7% statewide, and 212 tests (21.9%) fell between 2 and 4, against 24.9% statewide.

Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 35.5% share point the same way here. USGS geology rates 87% of the county's land high radon potential. CDC also counts 81 tests taken after mitigation in Montgomery County for the same period: tests in homes where a fix was already in.

CDC's ten-year totals for Montgomery County went from 972 tests (2005 to 2014) to 970 (2008 to 2017), the share going from 33.1% to 35.5%.

Montgomery County against Virginia, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Montgomery County
Montgomery County97035.5%2.5 pCi/LThis county
Virginia, pooled131 counties, pooled53,19930.4%Not pooled−5.1 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+0.2 points
Russell Countyhighest in the state4967.3%6.7 pCi/L+31.8 points
Norfolk citylowest in the state732.7%0.5 pCi/L−32.8 points
Giles County, VAborders it17456.9%4.8 pCi/L+21.4 points
Pulaski County, VAborders it26849.6%3.9 pCi/L+14.1 points
Craig County, VAborders it1346.2%2.8 pCi/L+10.7 points
Floyd County, VAborders it5442.6%3.3 pCi/L+7.1 points
Radford city, VAborders it9841.8%3.2 pCi/L+6.3 points
Roanoke County, VAborders it1,54122.1%1.9 pCi/L−13.4 points
Where Montgomery County's reported results fell, 2008 to 2017, laboratory, beside Virginia and the United States
ResultMontgomery County testsMontgomery County shareVirginia shareU.S. shareAgainst Virginia
Under 2 pCi/L41442.7%44.7%39.6%−2.0 points
2 to 4 pCi/L21221.9%24.9%24.7%−3.0 points
4 pCi/L and above34435.5%30.4%35.7%+5.1 points
Montgomery 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
Warren County37 of 8453636.9%2.7 pCi/L
Amherst County38 of 8424736.8%2.9 pCi/L
Shenandoah County39 of 8439036.4%2.7 pCi/L
Orange County40 of 8446236.1%2.8 pCi/L
Henry County41 of 8411535.7%2.7 pCi/L
Montgomery County42 of 8497035.5%2.5 pCi/L
Danville city43 of 847735.1%3.0 pCi/L
Greene County44 of 8421434.6%2.8 pCi/L
Spotsylvania County45 of 841,87234.2%2.7 pCi/L
Salem city46 of 8428633.6%2.8 pCi/L
Harrisonburg city47 of 8459933.4%2.4 pCi/L
Montgomery County ten-year laboratory totals, against Virginia's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestVirginia, pooledChange from the row before
2008 to 201797035.5%2.5 pCi/L90.9 pCi/L30.4%−1.1 points
2007 to 201698336.6%2.6 pCi/L90.9 pCi/L30.6%+1.4 points
2006 to 201596335.2%2.4 pCi/L90.9 pCi/L30.7%+2.1 points
2005 to 201497233.1%2.2 pCi/L90.9 pCi/L30.3%First on file

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

Montgomery County, Geology

The ground under Montgomery County

Predicted

Most of the ground under Montgomery County is one class on USGS's geologic map: 87.0% of its land is high radon potential, with 13.0% moderate. The map puts 87.0% of Montgomery County in the area it calls Valley and Ridge and 13.0% 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 Montgomery 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.High1587.0%
Blue RidgeGranite, pegmatite, monazite, schist, and gneiss.Moderate1013.0%

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

Montgomery County beside the ground around it

Montgomery County has more high-potential ground than Virginia as a whole: 87.0% of its land against 47.9%. Of the 6 counties that border it, 4 have more high-potential ground, Radford city the most at 100%.

Share of land by USGS radon potential: Montgomery County, the 6 counties bordering it and Virginia
AreaEPA zoneLow potentialModerate potentialHigh potential
Montgomery CountyZone 1None13.0%87.0%
Radford cityZone 1NoneNone100%
Roanoke CountyZone 1None34.6%65.4%
Floyd CountyZone 2None100%None
Giles CountyZone 1NoneNone100%
Pulaski CountyZone 1None2.5%97.5%
Craig 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

Montgomery County, Local resources

Radon testing and mitigation in Montgomery 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

Montgomery County, Questions

Questions about radon in Montgomery County

Are radon levels high in Montgomery County?

Over the 2008 to 2017 laboratory totals, 35.5% of the radon tests reported to CDC for Montgomery County, Virginia were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.5 pCi/L. Of 84 Virginia counties with 30 or more tests for the same period, 41 reported a higher share; pooled, the state comes to 30.4%.

Which counties border Montgomery County?

Montgomery County borders 6 counties: Radford city, Roanoke County, Floyd County, Giles County, Pulaski County and Craig County.

Products

Montgomery County, Products

Testing a home in Montgomery County

In Montgomery County, 35.5% of 970 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 Montgomery 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

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

Explore

Montgomery County, Bordering counties

Counties bordering Montgomery County

Calculated by Radon411

Montgomery County, Cities and towns

Cities and towns in Montgomery County

About 98,434 people live in Montgomery County by the Census Bureau's estimate for July 1, 2025, 1,159 fewer than in 2020 (−1.2%). That works out to 254 people per square mile of land. Its largest town, Blacksburg, has 45,104 residents, 45.8% of the total. Together its 2 incorporated places hold 68.6% of those residents; the other 31.4% live outside any of them. Testing is reported here more often than across the state: CDC's 970 reported tests for 2008 to 2017 come to 9.9 for every 1,000 residents (2025 estimate), against 6.0 for Virginia.

From Blacksburg to Christiansburg, CDC publishes no figure by town: each reads Montgomery County's.

The cities and towns in Montgomery County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Blacksburg45,104+0.8%45.8%
Christiansburg22,442−3.7%22.8%

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).

Montgomery County, Homes

Homes in Montgomery County

Fewer than six in ten of Montgomery County's 42,229 homes are detached houses (53%, against 61% across Virginia); the rest are attached, in shared buildings or mobile. Half of its homes were built before 1986, close to Virginia's 1984: 15% date from before 1960 and 28% from 2000 or later. 55% of occupied homes are lived in by their owner (Virginia: 67%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Montgomery County, Virginia, 2019 to 2023
HomesMontgomery CountyVirginia
Housing units42,2293,654,784
Detached houses53%61%
In buildings of 5 or more23%19%
Mobile homes10%4%
Built before 196015%19%
Built since 200028%25%
Middle year built19861984
Owner-occupied55%67%

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