Radon zones in Delaware
Last updated
EPA’s Map of Radon Zones places 3 Delaware counties in its three radon potential zones: 0 in Zone 1 (highest), 1 in Zone 2 (moderate), and 2 in Zone 3 (low).
What this means for Delaware homes
Most Delaware counties fall in Zone 3. EPA predicts lower average indoor levels (below 2 pCi/L) across much of Delaware. That does not mean your home is low: EPA notes that elevated levels are found in Zone 3 counties too.
EPA’s guidance is the same everywhere: test your home, fix it if the level is 4 pCi/L or higher, and consider fixing between 2 and 4 pCi/L. The zone map is from 1993 and should not be used to decide whether a single home needs testing.
Delaware radon program
EPA lists the following state contact for Delaware: DEHSS Division of Public Health, Office of Healthy Environments, Radon Program, phone 302-744-4727. Website: dhss.delaware.gov. State programs can tell you about local testing data, free or discounted test kits, disclosure rules for home sales, and credentialed radon professionals.
Delaware counties and their EPA radon zones
| County | EPA radon zone |
|---|---|
| Kent County | Zone 3 |
| New Castle County | Zone 2 |
| Sussex County | Zone 3 |
County names follow the 2020 Census. Zones from the EPA Map of Radon Zones (text version). Rows marked “zone of” use the zone EPA gave the predecessor or surrounding county.
Next steps: read how to test your home, check a result with the level calculator, or look up a single address by ZIP code.