Radon in Windham County, Connecticut

About 3 in 10 homes tested here were at or above the EPA action level.

837 home tests, 2008–2017, CDC lab data
  • Below 2 pCi/L: 42%
  • 2 to 4 pCi/L: 24%
  • 4 pCi/L or more: 34%
The line marks the EPA action level, 4 pCi/L.
Median level
2.6 pCi/L
EPA radon zone
Zone 2
In Connecticut
1st of 8

EPA Zone 2, moderate radon potential (predicted average 2 to 4 pCi/L). The EPA zone map dates from 1993 and is meant for planning; high levels are found in every zone.

What to do next

  1. Test your home

    Radon levels vary between neighboring houses, so area data can't tell you your own home's level. A short-term test takes 2 to 7 days in the lowest lived-in floor. A long-term test (90 days or more) gives a more reliable average.

  2. If your result is 4 pCi/L or more, fix it

    Most homes are fixed with a sub-slab depressurization system: a pipe and a quiet fan that pull radon from under the foundation and vent it above the roof. We're still collecting real installation prices for Connecticut.

  3. Use a certified professional

    Look for a professional certified by the National Radon Proficiency Program (NRPP) or the National Radon Safety Board (NRSB), or by your state if it certifies radon contractors.

How Windham County compares

Share of homes tested at or above 4 pCi/L, with neighboring counties. Lab data 2008–2017, the only source that covers every state.

Share of homes tested at or above 4 pCi/L
United States36%
Windham County34%
Connecticut26%

Sources

Last updated October 2026. How we calculate these numbers.