Radon in Vermont: radon map by county

EPA's Map of Radon Zones puts 0 of Vermont's 14 counties in Zone 1 (predicted average indoor radon above 4 pCi/L), 12 in Zone 2 and 2 in Zone 3. Of 7,200 building tests that radon laboratories reported for 2008 to 2017, 22.3% were at or above EPA's 4 pCi/L action level, against 36.5% nationally (number 35 of 42 states with 1,000+ tests). The highest county share is Orange County (38.1% of 288 tests).

counties in Zone 1 (above 4 pCi/L predicted)

counties in Zone 2 (2 to 4)

counties in Zone 3 (below 2)

22.3%

of 7,200 lab tests at or above 4 pCi/L

Radon by county in Vermont

EPA radon zone and radon test results for each county in Vermont
County	EPA zone	Lab tests	Median	4+ pCi/L
Addison County	Zone 2	286	1.7	21.7%
Bennington County	Zone 2	664	2.0	25.8%
Caledonia County	Zone 2	99	2.7	37.3%
Chittenden County	Zone 3	1,375	1.4	13.6%
Essex County	Zone 2	11	2.8	33.3%
Franklin County	Zone 2	158	1.3	11.9%
Grand Isle County	Zone 3	36	2.6	35.8%
Lamoille County	Zone 2	375	2.1	22.4%
Orange County	Zone 2	288	2.9	38.1%
Orleans County	Zone 2	69	1.8	24.6%
Rutland County	Zone 2	904	1.9	24.5%
Washington County	Zone 2	754	2.2	25%
Windham County	Zone 2	993	1.7	18.4%
Windsor County	Zone 2	1,188	2.2	26.3%

Lab tests: buildings tested by radon laboratories, 2008 to 2017; median in pCi/L; “4+ pCi/L” is the share of tests at or above EPA's action level. n/a: no value on file (no tests, or too few to report).

What the zones mean

Zone 1 counties have a predicted average indoor radon screening level above 4 pCi/L, Zone 2 from 2 to 4 pCi/L and Zone 3 below 2 pCi/L. The prediction is from 1993 indoor measurements, geology, aerial radioactivity, soils and foundation types. EPA: “This map should not be used to determine if individual homes need to be tested.” EPA recommends fixing a home at 4 pCi/L or more and considering a fix between 2 and 4 pCi/L, because there is no known safe level of exposure.

Radon in Vermont: questions

What radon zone is Vermont?

EPA's 1993 map does not give states one zone; it zones each county. In Vermont, 0 counties are Zone 1, 12 Zone 2 and 2 Zone 3. EPA says the map "should not be used to determine if individual homes need to be tested".

Which Vermont counties have the highest radon levels?

By the share of laboratory tests at or above 4 pCi/L for 2008 to 2017 (counties with 20 or more tests): Orange County 38.1% (median 2.9 pCi/L, 288 tests); Caledonia County 37.3% (median 2.7 pCi/L, 99 tests); Grand Isle County 35.8% (median 2.6 pCi/L, 36 tests); Windsor County 26.3% (median 2.2 pCi/L, 1,188 tests); Bennington County 25.8% (median 2.0 pCi/L, 664 tests).

How common is high radon in Vermont?

22.3% of the 7,200 tests in the laboratory data for Vermont (2008 to 2017) were at or above 4 pCi/L; the national share was 36.5%. Buildings are tested by choice, often because of a sale or a concern, so the share describes the tests on file, not every home.

Does Vermont publish its own radon test data?

Vermont's radon program reports county test results; the latest year with county results is 2023, shown on each county page.

Should I test for radon in Vermont?

Yes. EPA recommends testing every home no matter where it is, fixing it at 4 pCi/L or more and considering a fix between 2 and 4 pCi/L, because there is no known safe level of radon exposure.

States bordering Vermont

Radon in Massachusetts (3 of 14 in Zone 1)Radon in New Hampshire (1 of 10 in Zone 1)Radon in New York (34 of 62 in Zone 1)

Other free hazard lookups

All of these, plus wetlands, FEMA hazard ratings and the federal contamination lists, are in the Environmental Records Report for any US address ($29).

Superfund sites in Vermont · Radon map of every state

Data compiled 2026-10-20. County-level screening information, not a radon measurement of any building.