Skip to content
RADON411

Locations and reports

Radon Levels in Orange County, Virginia

EPA puts Orange County in Zone 1, its highest radon zone, and 36.1% of its 462 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

    36.1%

    5.7 pts above VA

    Orange
    36.1%
    Virginia
    30.4%

    462 tests, 2008 to 2017

  • Median result

    2.8pCi/L

    Below action level

    Orange
    2.8 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    462

    28th of 84 by tests

    Orange
    462
    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

    40 of 84

    Middle half

    Orange
    36.1%
    Russell
    67.3%

    By share, of 84 with 30+ tests

Read a result for Orange County

Starts at Orange County's median, 2.8 pCi/L

2.8pCi/L

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

EPA’s reading of 2.8 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. Orange County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Orange County, At a glance

Orange County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

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

Reported results by concentration band, Orange County, 2008 to 2017, laboratory
Under 2 pCi/L: 34%2 to 4 pCi/L: 30%4 pCi/L and above: 36%

Of 462 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Orange County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L15633.8%
2 to 4 pCi/L13930.1%
4 pCi/L and above16736.1%
What these figures count

These are the 462 tests reported to CDC for Orange 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

Orange County, Compared

Orange County radon figures, compared

Calculated by Radon411

In Orange County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (167 of 462) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 0.4 points higher. Across 131 Virginia counties pooled together, 30.4% of tests reached that level, so Orange County runs 5.7 points above its state.

Of 6 neighbours with a figure, 3 reported a larger share at or above 4 pCi/L and 3 a smaller one; the spread is 24.7% (Albemarle County) to 44.0% (Madison County). By share, Orange County is 40th of 84 Virginia counties with 30 or more tests for the same period.

Half the tests came in under 2.8 pCi/L and half over it; the single highest reached 53.8 pCi/L. Below the action level, 156 tests (33.8%) came in under 2 pCi/L, against 44.7% statewide, and 139 tests (30.1%) fell between 2 and 4, against 24.9% statewide.

Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 36.1% share point the same way here. USGS geology rates 87% of the county's land high radon potential. CDC also counts 37 tests taken after mitigation in Orange County for the same period: tests in homes where a fix was already in.

CDC's ten-year totals for Orange County went from 250 tests (2005 to 2014) to 462 (2008 to 2017), the share going from 36.0% to 36.1%.

Orange County against Virginia, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Orange County
Orange County46236.1%2.8 pCi/LThis county
Virginia, pooled131 counties, pooled53,19930.4%Not pooled−5.7 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−0.4 points
Russell Countyhighest in the state4967.3%6.7 pCi/L+31.2 points
Norfolk citylowest in the state732.7%0.5 pCi/L−33.4 points
Madison County, VAborders it18444.0%3.5 pCi/L+7.9 points
Culpeper County, VAborders it89140.1%3.2 pCi/L+4.0 points
Louisa County, VAborders it28938.1%2.8 pCi/L+2.0 points
Greene County, VAborders it21434.6%2.8 pCi/L−1.5 points
Spotsylvania County, VAborders it1,87234.2%2.7 pCi/L−1.9 points
Albemarle County, VAborders it2,17924.7%2.1 pCi/L−11.4 points
Where Orange County's reported results fell, 2008 to 2017, laboratory, beside Virginia and the United States
ResultOrange County testsOrange County shareVirginia shareU.S. shareAgainst Virginia
Under 2 pCi/L15633.8%44.7%39.6%−10.9 points
2 to 4 pCi/L13930.1%24.9%24.7%+5.2 points
4 pCi/L and above16736.1%30.4%35.7%+5.7 points
Orange 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
Mecklenburg County35 of 846637.9%3.0 pCi/L
James City County36 of 848337.3%2.6 pCi/L
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
Orange County ten-year laboratory totals, against Virginia's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestVirginia, pooledChange from the row before
2008 to 201746236.1%2.8 pCi/L53.8 pCi/L30.4%−1.5 points
2007 to 201639937.6%2.8 pCi/L53.8 pCi/L30.6%+0.6 points
2006 to 201532737.0%2.8 pCi/L53.8 pCi/L30.7%+1.0 points
2005 to 201425036.0%2.8 pCi/L53.8 pCi/L30.3%First on file

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

Orange County, Geology

The ground under Orange County

Predicted

Most of the ground under Orange County is one class on USGS's geologic map: 86.8% of its land is high radon potential, with 13.2% moderate. The map puts 86.8% of Orange County in the area it calls Inner Piedmont and 7.7% in Mesozoic Basins, with one smaller area beside them. USGS gives the first a radon index of 12, in the high band (12 to 17), and the second 11, in the moderate band (9 to 11).

USGS's geologic areas under Orange County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Inner PiedmontGranite, pegmatites, granitic gneiss, schist and gneiss, slate, and phyllite.High1286.8%
Mesozoic BasinsSandstone, siltstone and lacustrine black shale.Moderate117.7%
Blue RidgeGranite, pegmatite, monazite, schist, and gneiss.Moderate105.5%

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

Orange County beside the ground around it

Orange County has more high-potential ground than Virginia as a whole: 86.8% of its land against 47.9%. Of the 6 counties that border it, 2 have more high-potential ground, Louisa County the most at 100%.

Share of land by USGS radon potential: Orange County, the 6 counties bordering it and Virginia
AreaEPA zoneLow potentialModerate potentialHigh potential
Orange CountyZone 1None13.2%86.8%
Culpeper CountyZone 2None75.7%24.3%
Spotsylvania CountyZone 111.9%None88.1%
Madison CountyZone 2None99.5%0.5%
Louisa CountyZone 1NoneNone100%
Greene CountyZone 2None100%None
Albemarle CountyZone 2None71.1%28.9%
Virginia133 counties, pooled by land areaVaries20.6%30.0%47.9%

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

Local help

Orange County, Local resources

Radon testing and mitigation in Orange 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

Orange County, Questions

Questions about radon in Orange County

Are radon levels high in Orange County?

Over the 2008 to 2017 laboratory totals, 36.1% of the radon tests reported to CDC for Orange County, Virginia were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.8 pCi/L. Of 84 Virginia counties with 30 or more tests for the same period, 39 reported a higher share; pooled, the state comes to 30.4%.

Which counties border Orange County?

Orange County borders 6 counties: Culpeper County, Spotsylvania County, Madison County, Louisa County, Greene County and Albemarle County.

Products

Orange County, Products

Testing a home in Orange County

In Orange County, 36.1% of 462 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 Orange 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

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

Explore

Orange County, Bordering counties

Counties bordering Orange County

Calculated by Radon411

Orange County, Cities and towns

Cities and towns in Orange County

Orange County is growing: the Census Bureau puts it at 40,083 residents on July 1, 2025, up 10.1% from 36,396 in 2020. That works out to 118 people per square mile of land. No town dominates: Orange, the largest, has 5,365 residents, 13.4% of the total. Together its 2 incorporated places hold 17.3% of those residents; the other 82.7% live outside any of them. Testing is reported here more often than across the state: CDC's 462 reported tests for 2008 to 2017 come to 11.5 for every 1,000 residents (2025 estimate), against 6.0 for Virginia.

From Orange to Gordonsville, CDC publishes no figure by town: each reads Orange County's.

The cities and towns in Orange County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Orange5,365+9.5%13.4%
Gordonsville1,587+9.9%4.0%

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).

Orange County, Homes

Homes in Orange County

Orange County is a place of houses on their own lots: 82% of its 15,895 homes are detached single-family houses, against 61% across Virginia. Much of Orange County is recent building: 39% of its homes have gone up since 2000 and the middle year built is 1992, against 1984 for Virginia. 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 Orange County, Virginia, 2019 to 2023
HomesOrange CountyVirginia
Housing units15,8953,654,784
Detached houses82%61%
In buildings of 5 or more7%19%
Mobile homes4%4%
Built before 196017%19%
Built since 200039%25%
Middle year built19921984
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.