Connecticut Radon Levels
4Zone 1 (High)
3Zone 2 (Moderate)
1Zone 3 (Low)
50% of counties in Connecticut are classified as EPA Zone 1 (highest radon potential), meaning predicted average indoor radon levels exceed 4 pCi/L — the EPA action level. The EPA recommends that all homes be tested for radon, regardless of zone classification.
| County | EPA Zone | Risk Level |
|---|---|---|
| Fairfield County | Zone 1 | Highest Potential |
| Hartford County | Zone 3 | Lowest Potential |
| Litchfield County | Zone 2 | Moderate Potential |
| Middlesex County | Zone 1 | Highest Potential |
| New Haven County | Zone 1 | Highest Potential |
| New London County | Zone 1 | Highest Potential |
| Tolland County | Zone 2 | Moderate Potential |
| Windham County | Zone 2 | Moderate Potential |