Average Radon Levels in Connecticut: EPA Zone Data and What It Means

Radon Levels in Connecticut

Connecticut is classified as EPA Radon Zone 1, the highest risk category. The predicted average indoor radon screening level is above 4 pCi/L, the EPA action level.

What the EPA Zones Mean

Zone	Predicted Average	Risk Level
Zone 1	Above 4 pCi/L	High: immediate testing recommended for all homes
Zone 2	2 to 4 pCi/L	Moderate: testing recommended for all homes
Zone 3	Below 2 pCi/L	Lower: testing still recommended by the EPA

Zone classifications are based on geology, soil permeability, and housing characteristics at the county level. They represent average predictions. Individual homes within any zone can have radon levels significantly above or below the average. That is why the EPA recommends testing every home, regardless of zone.

Health Risks at Different Levels

Radon exposure is measured in picocuries per liter (pCi/L). For perspective:

1.3 pCi/L is the average outdoor radon level
4 pCi/L is the EPA action level. Living at this level carries roughly the same lung cancer risk as smoking 8 cigarettes per day
8 pCi/L is equivalent to smoking about half a pack per day
20 pCi/L carries a risk comparable to smoking 1 to 2 packs per day

Radon is the #1 cause of lung cancer among non-smokers and the #2 cause overall, responsible for approximately 21,000 lung cancer deaths per year in the United States.

Test Your Home

The only way to know your home's radon level is to test. Professional testing in Connecticut costs $125 to $350, or you can use a DIY test kit for $15 to $40. Find a certified radon tester in Connecticut through our directory.

Frequently Asked Questions

What EPA radon zone is Connecticut?

Connecticut is classified as EPA Radon Zone 1. Zone 1 means the predicted average indoor radon screening level is above 4 pCi/L.

Is radon a problem in Connecticut?

Yes. Connecticut is a high-radon state. A significant percentage of homes test above the EPA action level of 4 pCi/L.