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Radon Levels in Winchester city, Virginia

EPA puts Winchester city in Zone 1, its highest radon zone, and high results are common there: 44.8% of the 773 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

    44.8%

    14.4 pts above VA

    Winchester city
    44.8%
    Virginia
    30.4%

    773 tests, 2008 to 2017

  • Median result

    3.3pCi/L

    Below action level

    Winchester city
    3.3 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    773

    16th of 84 by tests

    Winchester city
    773
    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

    17 of 84

    Top quarter

    Winchester city
    44.8%
    Russell
    67.3%

    By share, of 84 with 30+ tests

Read a result for Winchester city

Starts at Winchester city's median, 3.3 pCi/L

3.3pCi/L

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

EPA’s reading of 3.3 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. Winchester city's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Winchester city, At a glance

Winchester city at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Winchester city 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 Winchester city, 2008 to 2017, laboratory

Reported results by concentration band, Winchester city, 2008 to 2017, laboratory
Under 2 pCi/L: 35%2 to 4 pCi/L: 20%4 pCi/L and above: 45%

Of 773 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Winchester city, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L27235.2%
2 to 4 pCi/L15520.1%
4 pCi/L and above34644.8%
What these figures count

These are the 773 tests reported to CDC for Winchester city 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

Winchester city, Compared

Winchester city radon figures, compared

Calculated by Radon411

In Winchester city, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (346 of 773) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 9.1 points higher. Across 131 Virginia counties pooled together, 30.4% of tests reached that level, so Winchester city runs 14.4 points above its state.

Frederick County, the one bordering county with a figure for the same period, reported 44.1%. By share, Winchester city is 17th of 84 Virginia counties with 30 or more tests for the same period.

Half the tests came in under 3.3 pCi/L and half over it; the single highest reached 79.7 pCi/L. Below the action level, 272 tests (35.2%) came in under 2 pCi/L, against 44.7% statewide, and 155 tests (20.1%) fell between 2 and 4, against 24.9% statewide.

Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 44.8% share point the same way here. USGS geology rates 100% of the county's land high radon potential. CDC also counts 21 tests taken after mitigation in Winchester city for the same period: tests in homes where a fix was already in.

CDC's ten-year totals for Winchester city went from 524 tests (2005 to 2014) to 773 (2008 to 2017), the share going from 49.4% to 44.8%.

Winchester city against Virginia, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Winchester city
Winchester city77344.8%3.3 pCi/LThis county
Virginia, pooled131 counties, pooled53,19930.4%Not pooled−14.4 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−9.1 points
Russell Countyhighest in the state4967.3%6.7 pCi/L+22.5 points
Norfolk citylowest in the state732.7%0.5 pCi/L−42.1 points
Frederick County, VAborders it2,45144.1%3.3 pCi/L−0.7 points
Where Winchester city's reported results fell, 2008 to 2017, laboratory, beside Virginia and the United States
ResultWinchester city testsWinchester city shareVirginia shareU.S. shareAgainst Virginia
Under 2 pCi/L27235.2%44.7%39.6%−9.5 points
2 to 4 pCi/L15520.1%24.9%24.7%−4.8 points
4 pCi/L and above34644.8%30.4%35.7%+14.4 points
Winchester city 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
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
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
Winchester city ten-year laboratory totals, against Virginia's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestVirginia, pooledChange from the row before
2008 to 201777344.8%3.3 pCi/L79.7 pCi/L30.4%−1.9 points
2007 to 201670046.7%3.5 pCi/L79.7 pCi/L30.6%−1.7 points
2006 to 201561248.4%3.8 pCi/L79.7 pCi/L30.7%−1.0 points
2005 to 201452449.4%3.9 pCi/L79.7 pCi/L30.3%First on file

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

Winchester city, Geology

The ground under Winchester city

Predicted

USGS's geologic map puts all of Winchester city'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 Winchester city
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.High15100%

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

Winchester city beside the ground around it

Winchester city has more high-potential ground than Virginia as a whole: 100% of its land against 47.9%. Of the one county that borders it, none has as large a share of high-potential ground; Frederick County comes nearest at 100%.

Share of land by USGS radon potential: Winchester city, the county bordering it and Virginia
AreaEPA zoneLow potentialModerate potentialHigh potential
Winchester cityZone 1NoneNone100%
Frederick 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

Winchester city, Local resources

Radon testing and mitigation in Winchester city

Listed radon professionals by town: Winchester

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

Winchester city, Questions

Questions about radon in Winchester city

Are radon levels high in Winchester city?

Over the 2008 to 2017 laboratory totals, 44.8% of the radon tests reported to CDC for Winchester city, Virginia were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.3 pCi/L. Of 84 Virginia counties with 30 or more tests for the same period, 16 reported a higher share; pooled, the state comes to 30.4%.

Which counties border Winchester city?

Winchester city borders 1 county: Frederick County.

Products

Winchester city, Products

Testing a home in Winchester city

In Winchester city, 44.8% of 773 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 Winchester city 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

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

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Winchester city, Bordering counties

Counties bordering Winchester city

Calculated by Radon411

Winchester city, Cities and towns

Cities and towns in Winchester city

The Census Bureau estimates 28,272 residents in Winchester city for July 1, 2025, 269 more than in 2020 (+1.0%). Packed into its land, that is 3,075 people per square mile. Winchester, its one incorporated place, has 28,272 residents, 100.0% of the total. Testing is reported here more often than across the state: CDC's 773 reported tests for 2008 to 2017 come to 27.3 for every 1,000 residents (2025 estimate), against 6.0 for Virginia.

Winchester is the one incorporated place here; CDC publishes no figure by town, so it reads Winchester city's.

Winchester, Winchester city: residents on July 1, 2025
PlaceResidentsSince 2020Share of residents
Winchester28,272+1.0%100.0%

One incorporated place, 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).

Winchester city, Homes

Homes in Winchester city

Of Winchester city's 12,468 homes, 58% are detached houses, against 61% across Virginia; 23% are in buildings of five or more homes. The homes are older than Virginia's as a whole: half were built before 1968 (1984 for Virginia), and 41% date from before 1960. Most occupied homes here are rented: owners live in 42% (Virginia: 67%). A tenant can run a test; a fix is the landlord's to make.

Homes in Winchester city, Virginia, 2019 to 2023
HomesWinchester cityVirginia
Housing units12,4683,654,784
Detached houses58%61%
In buildings of 5 or more23%19%
Mobile homes0%4%
Built before 196041%19%
Built since 200014%25%
Middle year built19681984
Owner-occupied42%67%

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