Short-term kitempowerDX
Standard Radon Test short-term mail-in radon test kit
- Lab fee included
Method: Passive sampler
In home: 48 to 96 hours
Locations and reports
Radon Levels in Washington County, Vermont
EPA puts Washington County in Zone 2, its middle radon zone, and 26.1% of its 199 reported radon tests (2023) 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
Share at 4+ pCi/L
26.1%
5.5 pts above VT
- Washington
- 26.1%
- Vermont
- 20.6%
199 tests, 2023
Median result
2.0pCi/L
Below action level
- Washington
- 2.0 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2023
Tests reported
199
2nd of 12 by tests
- Washington
- 199
- Chittenden
- 398
Reported to CDC before any fix, 2023
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Rank in Vermont
3 of 12
Top quarter
- Washington
- 26.1%
- Bennington
- 29.5%
By share, of 12 with 30+ tests
Read a result for Washington County
Starts at Washington County's median, 2.0 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.0 pCi/L
Between 2 and 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 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. Washington County's median reported result, 2023.
The data
Washington County, At a glance
Washington County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Washington County is a
USGS geologic potential: Moderate across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Washington County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 25.8% |
| 2015 | 23.8% |
| 2016 | 22.5% |
| 2017 | 22.5% |
| 2018 | 20.2% |
| 2019 | 16.4% |
| 2020 | 23.3% |
| 2021 | 25.0% |
| 2022 | 27.5% |
| 2023 | 26.1% |
2023: 26.1%. Across these years the share ran from 16.4% to 27.5%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 199 tests reported to CDC for Washington County over 2023, 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: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).
Washington County, Compared
Washington County radon figures, compared
Calculated by Radon411Washington County's 199 reported tests in 2023 had a middle value of 2.0 pCi/L and a maximum of 38.1 pCi/L, and 26.1% reached 4 pCi/L. Vermont as a whole (14 Vermont counties, pooled) comes to 20.6%: 5.5 points lower than here.
Among its state's counties it ranks 3rd of 12 Vermont counties with 30 or more tests for the same period. Statewide for the same period, Bennington County reported the highest share (29.5%) and Chittenden County the lowest (14.6%).
Below the action level, 99 tests (49.7%) came in under 2 pCi/L, against 56.8% statewide, and 48 tests (24.1%) fell between 2 and 4, against 22.5% statewide. The busiest year on file was 2022, with 579 tests reported; the quietest, 2015, had 84.
EPA's 1993 zone map puts Washington County in Zone 2, a predicted county average between 2 and 4 pCi/L. USGS geology rates 100% of the county's land moderate radon potential.
Next door, the shares run from 14.6% in Chittenden County to 26.4% in Orange County, with Lamoille County, Caledonia County and Addison County below Washington County. Over 10 years of annual figures the share held within 2 points, from 25.8% in 2014 to 26.1% in 2023; its peak was 27.5% in 2022.
CDC also counts 19 tests taken after mitigation in Washington County for the same period: tests in homes where a fix was already in.
Washington CountyVermont, pooled
| Year | Tests | Washington County, at or above 4 pCi/L | Vermont, pooled |
|---|---|---|---|
| 2014 | 120 | 25.8% | 18.3% |
| 2015 | 84 | 23.8% | 15.5% |
| 2016 | 169 | 22.5% | 15.9% |
| 2017 | 275 | 22.5% | 16.4% |
| 2018 | 258 | 20.2% | 15.8% |
| 2019 | 286 | 16.4% | 14.3% |
| 2020 | 373 | 23.3% | 16.5% |
| 2021 | 364 | 25.0% | 19.2% |
| 2022 | 579 | 27.5% | 19.4% |
| 2023 | 199 | 26.1% | 20.6% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Washington County, Geology
The ground under Washington County
PredictedUSGS's geologic map puts all of Washington County's mapped land in one class: moderate radon potential. The map puts 73.7% of Washington County in the area it calls Vermont Piedmont and 21.8% in Green Mountains, with one smaller area beside them. USGS gives both a radon index of 11, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Vermont Piedmont | Paleozoic metavolcanic and metasedimentary rocks that are intruded by igneous plutonic rocks. | Moderate | 11 | 73.7% |
| Green Mountains | Proterozoic to Paleozoic metaigneous and metasedimentary rocks. | Moderate | 11 | 21.8% |
| Vermont Piedmont | Granite and granitic gneiss of the New Hampshire plutonic series. | Moderate | 11 | 4.5% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Washington County beside the ground around it
Washington County has more moderate-potential ground than Vermont as a whole: 100% of its land against 87.8%. Of the 5 counties that border it, none has as large a share of moderate-potential ground; Lamoille County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Washington County, Local resources
Radon testing and mitigation in Washington County
- Radon ProgramRadon Program, run by Vermont Department of Health, offers free or discounted test kits, and answers questions about testing and mitigation in Vermont.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
Join the Department of Health Lab's study on radon in water to receive free test kits for your well or spring.
- Compare kits
- See the Vermont directoryNo professionals are listed in Vermont yet. The state program can point you to registered testers and mitigators.
What Vermont's program says
- Phone
- 802-863-7220
What it means
Washington County, Questions
Questions about radon in Washington County
Are radon levels high in Washington County?
In 2023, 26.1% of the radon tests reported to CDC for Washington County, Vermont were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.0 pCi/L. Of 12 Vermont counties with 30 or more tests for the same period, 2 reported a higher share; pooled, the state comes to 20.6%.
Which counties border Washington County?
Washington County borders 5 counties: Orange County, Chittenden County, Lamoille County, Addison County and Caledonia County.
Products
Washington County, Products
Testing a home in Washington County
In Washington County, 26.1% of 199 tests reported to CDC in 2023 reached 4 pCi/L, against 20.6% pooled across Vermont. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Washington County; a long-term test tells the year-round average.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL416 long-term radon test kit, lab fee included
- Lab fee included
Method: Alpha track
In home: 90 days to 12 months
Monitor
EcoQube Wi-Fi continuous radon monitor
- C-NRPP 2024/25: Approved
- Plug-in
- Wi-Fi
- App only
Method: Ion chamber
First reading: Within 10 minutes
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Washington County, Bordering counties
Counties bordering Washington County
Calculated by Radon411- Radon levels in Orange CountyEPA zone 2
26.4%at or above 4 pCi/L
Median 2.5 pCi/L · 53 tests · 0.3 points above Washington County
- Radon levels in Lamoille CountyEPA zone 2
22.6%at or above 4 pCi/L
Median 1.8 pCi/L · 62 tests · 3.5 points below Washington County
- Radon levels in Caledonia CountyEPA zone 2
21.1%at or above 4 pCi/L
Median 2.0 pCi/L · 76 tests · 5.0 points below Washington County
- Radon levels in Addison CountyEPA zone 2
19.3%at or above 4 pCi/L
Median 1.7 pCi/L · 83 tests · 6.8 points below Washington County
- Radon levels in Chittenden CountyEPA zone 3
14.6%at or above 4 pCi/L
Median 1.3 pCi/L · 398 tests · 11.5 points below Washington County
Washington County, Cities and towns
Cities and towns in Washington County
Washington County's population has barely moved since 2020: 59,652 residents on July 1, 2025 against 59,766 then, by the Census Bureau's estimates. That works out to 87 people per square mile of land. No town dominates: Barre, the largest, has 8,214 residents, 13.8% of the total. Together its 3 incorporated places hold 27.3% of those residents; the other 72.7% live outside any of them. Testing is reported here more often than across the state: CDC's 199 reported tests for 2023 come to 3.3 for every 1,000 residents (2025 estimate), against 2.0 for Vermont.
From Barre to Marshfield, CDC publishes no figure by town: each reads Washington County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Barre | 8,214 | −3.0% | 13.8% |
| Montpelier | 7,823 | −2.9% | 13.1% |
| Marshfield | 267 | −0.4% | 0.4% |
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).
Washington County, Homes
Homes in Washington County
Of Washington County's 30,860 homes, 65% are detached houses, against 67% across Vermont; 11% are in buildings of five or more homes. Half of its homes were built before 1972, close to Vermont's 1976: 36% date from before 1960 and 14% from 2000 or later. 73% of occupied homes are lived in by their owner (Vermont: 73%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Washington County | Vermont |
|---|---|---|
| Housing units | 30,860 | 337,072 |
| Detached houses | 65% | 67% |
| In buildings of 5 or more | 11% | 11% |
| Mobile homes | 6% | 6% |
| Built before 1960 | 36% | 33% |
| Built since 2000 | 14% | 17% |
| Middle year built | 1972 | 1976 |
| Owner-occupied | 73% | 73% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.