Radon levels in Vermont: Low
The model predicts a population-weighted basement average of 1.7 pCi/L (model estimate) across Vermont's 14 counties - close to the US average of 1.8 pCi/L. Above-ground floors average 1.0 pCi/L.
Predicted (model estimate). The pCi/L figures on this page are long-term area averages from a peer-reviewed national model built on millions of real radon tests (2001-2021). They describe the typical home in this area - not your home, which can be several times higher or lower. The EPA radon zone is a separate, 1993 county-level classification. Measured state test results are shown separately below, labeled with their source and years. How the numbers work.
0 / 14
EPA Zone 1 counties (0%)
12 / 2
Zone 2 / Zone 3 counties
0
counties predicted ≥ 4 pCi/L
15.2%
of measured tests ≥ 4 pCi/L (1994-2025)
Test Vermont once anyway - radon varies house to house
The predicted basement average here is 1.7 pCi/L, below the EPA's 2 pCi/L "consider fixing" threshold. That's good news for the area - but the EPA still recommends every home be tested, because foundation cracks, soil pockets and ventilation make one house very different from its neighbor. One inexpensive kit settles it.
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What the data says about radon in Vermont
0 of Vermont's 14 counties are EPA Zone 1 (0%), 12 are Zone 2 and 2 are Zone 3 on the EPA's county-level map. Zone 2 (predicted screening average of 2-4 pCi/L) is the most common designation. The zones were drawn once, from geology and the tests available in 1993, and the EPA itself notes that homes with elevated radon exist in all three zones.
Weighted by where people live, Vermont's predicted basement average is 1.7 pCi/L - close to the US average of 1.8 - which puts the state in the low range. Of the 14 counties with predictions, 0 are predicted at or above 4 pCi/L, 0 in the 2-4 band and 14 below 2. The county range is narrow: from Chittenden County at 1.36 to Bennington County at 1.98 pCi/L, a spread of only 0.62.
Nationally 4.2% of ZIPs are predicted at 4+ pCi/L and 48.7% at 2+; in Vermont it is 0% and 13.6% - below the national figures on both counts. No ZIP in the state is predicted above 4 on average - but averages hide individual homes, which is why the EPA still asks everyone to test.
Measured data exists for Vermont: Vermont Department of Health publishes 1994-2025 results for 14 counties (26,805 tested residences). Weighted by test count, 15.2% of results are at or above 4 pCi/L. The county with the largest share of elevated results is Orange County (24.5%); the smallest is Franklin County (9%). This source publishes no county means, so it cannot be compared with the model directly; each county page shows the measured share alongside the prediction.
Vermont counties by predicted radon
Sorted highest to lowest predicted basement average (model estimate). 14 counties. The “Measured ≥ 4” column is the share of Vermont Department of Health test results at or above 4 pCi/L, 1994-2025.
| County | Predicted basement | Upstairs | Grade | EPA zone | Measured ≥ 4 | ZIPs |
|---|---|---|---|---|---|---|
| Bennington County | 2.0 pCi/L | 1.2 | Low | EPA Zone 2 | 18.7% | 15 |
| Washington County | 2.0 pCi/L | 1.1 | Low | EPA Zone 2 | 20.6% | 18 |
| Windsor County | 1.9 pCi/L | 1.1 | Low | EPA Zone 2 | 16.4% | 28 |
| Essex County | 1.9 pCi/L | 1.1 | Low | EPA Zone 2 | 20.5% | 11 |
| Orange County | 1.9 pCi/L | 1.1 | Low | EPA Zone 2 | 24.5% | 26 |
| Windham County | 1.9 pCi/L | 1.0 | Low | EPA Zone 2 | 13.1% | 23 |
| Orleans County | 1.8 pCi/L | 1.0 | Low | EPA Zone 2 | 14.5% | 22 |
| Caledonia County | 1.8 pCi/L | 1.1 | Low | EPA Zone 2 | 24.2% | 14 |
| Lamoille County | 1.8 pCi/L | 1.0 | Low | EPA Zone 2 | 14.9% | 11 |
| Rutland County | 1.8 pCi/L | 1.1 | Low | EPA Zone 2 | 15.7% | 25 |
| Franklin County | 1.6 pCi/L | 0.9 | Low | EPA Zone 2 | 9% | 13 |
| Addison County | 1.6 pCi/L | 0.8 | Low | EPA Zone 2 | 15.8% | 15 |
| Grand Isle County | 1.5 pCi/L | 0.8 | Low | EPA Zone 3 | 21% | 5 |
| Chittenden County | 1.4 pCi/L | 0.8 | Low | EPA Zone 3 | 10.2% | 16 |
Radon levels in Vermont cities
The one most-populous Vermont place among the 1,000 largest US cities (Census incorporated places and CDPs), by population. City figures are ZIP-land-weighted means of the model's ZIP predictions (model estimate).
| City | Population | Predicted basement | Upstairs | Grade | ZIPs ≥ 4 |
|---|---|---|---|---|---|
| Burlington | 44,528 | 1.2 pCi/L | 0.7 | Low | 0% |
Highest-radon ZIP codes in Vermont
The 10 Vermont ZIP codes with the highest predicted basement average (model estimate), out of 242 modeled. A ZIP average is still an area figure - neighboring homes routinely test several pCi/L apart.
| ZIP | County | Predicted basement | Upstairs | Grade |
|---|---|---|---|---|
| 05048 | Windsor County | 3.7 pCi/L | 1.4 | Moderate |
| 05060 | Orange County | 2.4 pCi/L | 1.3 | Moderate |
| 05149 | Windsor County | 2.4 pCi/L | 1.2 | Moderate |
| 05641 | Washington County | 2.3 pCi/L | 1.0 | Moderate |
| 05363 | Windham County | 2.2 pCi/L | 1.1 | Moderate |
| 05089 | Windsor County | 2.2 pCi/L | 1.3 | Moderate |
| 05737 | Rutland County | 2.2 pCi/L | 1.4 | Moderate |
| 05250 | Bennington County | 2.1 pCi/L | 1.3 | Moderate |
| 05761 | Rutland County | 2.1 pCi/L | 1.2 | Moderate |
| 05035 | Windsor County | 2.1 pCi/L | 1.3 | Moderate |
Vermont radon questions
- Is radon high in Vermont?
- Vermont's population-weighted predicted basement average is 1.7 pCi/L, close to the US average of 1.8. 0 of its 14 modeled counties are predicted at or above the EPA action level of 4 pCi/L, 0 are in the 2-4 "consider fixing" range and 14 are below 2. 0% of Vermont ZIP codes are predicted at 4 or higher.
- Which Vermont county has the highest radon?
- Bennington County has the highest predicted basement average in Vermont at 2.0 pCi/L (EPA Zone 2). The lowest is Chittenden County at 1.4 pCi/L. In measured state test data (1994-2025), Orange County has the largest share of results at or above 4 pCi/L (24.5%). These are area figures; individual homes in any county can test far higher.
- How many EPA Zone 1 counties are in Vermont?
- 0 of Vermont's 14 counties (0%) are EPA Zone 1 (highest potential), 12 are Zone 2 and 2 are Zone 3. The EPA zone map dates from 1993; the predicted values on this page come from a 2001-2021 model built on millions of actual tests, so the two can disagree for a given county.
- Should I test for radon in Vermont?
- Yes. Even though Vermont's predicted average is below 2 pCi/L, the EPA recommends every home be tested - radon varies house to house, and 13.6% of Vermont ZIP codes are still predicted at 2 pCi/L or higher.
Vermont radon program
Vermont's radon program page is at www.healthvermont.gov; it lists testing and certified-mitigator guidance for the state. The EPA also keeps a directory of every state radon contact: EPA state radon contacts page. Then read how to test and what mitigation costs.