Short-term kitFirst Alert
RD1 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 2 to 4 days
Locations and reports
Radon Levels in Franklin County, Vermont
EPA puts Franklin County in Zone 2, its middle radon zone, and 23.4% of its 47 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
23.4%
2.8 pts above VT
- Franklin
- 23.4%
- Vermont
- 20.6%
47 tests, 2023
Median result
1.5pCi/L
Below action level
- Franklin
- 1.5 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2023
Tests reported
47
11th of 12 by tests
- Franklin
- 47
- 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
4 of 12
Middle half
- Franklin
- 23.4%
- Bennington
- 29.5%
By share, of 12 with 30+ tests
Read a result for Franklin County
Starts at Franklin County's median, 1.5 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 1.5 pCi/L
Below 2 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is below 2 pCi/L, the level at which EPA says a fix should be considered. Franklin County's median reported result, 2023.
The data
Franklin County, At a glance
Franklin County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Franklin County is a
USGS geologic potential: Moderate across 68% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Franklin County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 19.1% |
| 2015 | 6.5% |
| 2016 | 14.9% |
| 2017 | 14.1% |
| 2018 | 12.5% |
| 2019 | 4.2% |
| 2020 | 8.4% |
| 2021 | 15.3% |
| 2022 | 14.9% |
| 2023 | 23.4% |
2023: 23.4%. Across these years the share ran from 4.2% to 23.4%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 47 tests reported to CDC for Franklin 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).
Franklin County, Compared
Franklin County radon figures, compared
Calculated by Radon411Franklin County's 47 reported tests in 2023 had a middle value of 1.5 pCi/L and a maximum of 12.3 pCi/L, and 23.4% reached 4 pCi/L. Vermont as a whole (14 Vermont counties, pooled) comes to 20.6%: 2.8 points lower than here.
Among its state's counties it ranks 4th 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, 27 tests (57.4%) came in under 2 pCi/L, against 56.8% statewide, and 9 tests (19.1%) fell between 2 and 4, against 22.5% statewide. The busiest year on file was 2022, with 141 tests reported; the quietest, 2015, had 31.
EPA's 1993 zone map puts Franklin County in Zone 2, a predicted county average between 2 and 4 pCi/L. USGS geology rates 68% of the county's land moderate radon potential.
Next door, the shares run from 14.6% in Chittenden County to 22.6% in Lamoille County, with Lamoille County, Orleans County and Chittenden County below Franklin County. Over 10 years of annual figures the share rose 4.3 points, from 19.1% in 2014 to 23.4% in 2023; its peak was 23.4% in 2023.
Franklin CountyVermont, pooled
| Year | Tests | Franklin County, at or above 4 pCi/L | Vermont, pooled |
|---|---|---|---|
| 2014 | 47 | 19.1% | 18.3% |
| 2015 | 31 | 6.5% | 15.5% |
| 2016 | 47 | 14.9% | 15.9% |
| 2017 | 99 | 14.1% | 16.4% |
| 2018 | 56 | 12.5% | 15.8% |
| 2019 | 71 | 4.2% | 14.3% |
| 2020 | 131 | 8.4% | 16.5% |
| 2021 | 72 | 15.3% | 19.2% |
| 2022 | 141 | 14.9% | 19.4% |
| 2023 | 47 | 23.4% | 20.6% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Franklin County, Geology
The ground under Franklin County
PredictedUSGS's geologic map splits Franklin County: 68.1% of its land is moderate radon potential and 31.7% low. The map puts 68.1% of Franklin County in the area it calls Green Mountains and 31.7% in Champlain Lowland. USGS gives the first a radon index of 11, in the moderate band (9 to 11), and the second 8, in the low band (5 to 8).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Green Mountains | Proterozoic to Paleozoic metaigneous and metasedimentary rocks. | Moderate | 11 | 68.1% |
| Champlain Lowland | Cambrian-Ordovician sedimentary rocks with little or low-grade metamorphism. | Low | 8 | 31.7% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Franklin County beside the ground around it
Vermont as a whole has more moderate-potential ground than Franklin County: 87.8% of its land, against 68.1% here. Of the 4 counties that border it, 2 have more moderate-potential ground, Lamoille County the most at 100%.
The map rates the ground, not the air in any home.
Local help
Franklin County, Local resources
Radon testing and mitigation in Franklin 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
Franklin County, Questions
Questions about radon in Franklin County
Are radon levels high in Franklin County?
In 2023, 23.4% of the radon tests reported to CDC for Franklin County, Vermont were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.5 pCi/L. Of 12 Vermont counties with 30 or more tests for the same period, 3 reported a higher share; pooled, the state comes to 20.6%.
Which counties border Franklin County?
Franklin County borders 4 counties: Lamoille County, Grand Isle County, Chittenden County and Orleans County.
Products
Franklin County, Products
Testing a home in Franklin County
In Franklin County, 23.4% of 47 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 Franklin County; a long-term test tells the year-round average.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
MonitorAEGTEST
HOUND-1011S rechargeable radon detector with a screen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 12 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Franklin County, Bordering counties
Counties bordering Franklin County
Calculated by Radon411- Radon levels in Grand Isle CountyEPA zone 3
30.0%at or above 4 pCi/L
Median 1.5 pCi/L · 20 tests · 6.6 points above Franklin County
- Radon levels in Lamoille CountyEPA zone 2
22.6%at or above 4 pCi/L
Median 1.8 pCi/L · 62 tests · 0.8 points below Franklin County
- Radon levels in Orleans CountyEPA zone 2
21.6%at or above 4 pCi/L
Median 1.7 pCi/L · 51 tests · 1.8 points below Franklin County
- Radon levels in Chittenden CountyEPA zone 3
14.6%at or above 4 pCi/L
Median 1.3 pCi/L · 398 tests · 8.8 points below Franklin County
Franklin County, Cities and towns
Cities and towns in Franklin County
The Census Bureau estimates 51,177 residents in Franklin County for July 1, 2025, 1,136 more than in 2020 (+2.3%). That works out to 81 people per square mile of land. No town dominates: St. Albans, the largest, has 6,939 residents, 13.6% of the total. Together its 3 incorporated places hold 20.8% of those residents; the other 79.2% live outside any of them. Reported testing is thin here: 47 tests over 2023, or 0.9 for every 1,000 residents (2025 estimate), where Vermont as a whole comes to 2.0.
From St. Albans to Enosburg Falls, CDC publishes no figure by town: each reads Franklin County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| St. Albans | 6,939 | +1.6% | 13.6% |
| Swanton | 2,380 | +1.4% | 4.7% |
| Enosburg Falls | 1,329 | −1.8% | 2.6% |
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).
Franklin County, Homes
Homes in Franklin County
Of Franklin County's 22,850 homes, 75% are detached houses, against 67% across Vermont; 6% are mobile homes. Half of its homes were built before 1979, close to Vermont's 1976: 33% date from before 1960 and 24% from 2000 or later. Owners live in 78% of the occupied homes (Vermont: 73%), so for most households a test and a fix are their own to order.
| Homes | Franklin County | Vermont |
|---|---|---|
| Housing units | 22,850 | 337,072 |
| Detached houses | 75% | 67% |
| In buildings of 5 or more | 6% | 11% |
| Mobile homes | 6% | 6% |
| Built before 1960 | 33% | 33% |
| Built since 2000 | 24% | 17% |
| Middle year built | 1979 | 1976 |
| Owner-occupied | 78% | 73% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.