Radon levels in Delaware: Low
The model predicts a population-weighted basement average of 1.3 pCi/L across Delaware's 3 counties - about 26% below the US average of 1.8 pCi/L. Above-ground floors average 0.8 pCi/L.
Predicted (model estimate). The pCi/L figures on this page are long-term area averages from a peer-reviewed national model built on millions of real radon tests (2001-2021). They describe the typical home in this area - not your home, which can be several times higher or lower. The EPA radon zone is a separate, 1993 county-level classification. How the numbers work.
0 / 3
EPA Zone 1 counties (0%)
1 / 2
Zone 2 / Zone 3 counties
0
counties predicted ≥ 4 pCi/L
0%
of ZIP codes predicted ≥ 4 pCi/L
Delaware counties by predicted radon
Sorted highest to lowest predicted basement average. 3 counties.
| County | Predicted basement | Upstairs | Grade | EPA zone | ZIPs |
|---|---|---|---|---|---|
| Sussex County | 1.4 pCi/L | 0.7 | Low | EPA Zone 3 | 22 |
| Kent County | 1.4 pCi/L | 0.7 | Low | EPA Zone 3 | 13 |
| New Castle County | 1.3 pCi/L | 0.9 | Low | EPA Zone 2 | 24 |
Delaware radon questions
- Is radon high in Delaware?
- Delaware's population-weighted predicted basement average is 1.3 pCi/L, about 26% below the US average of 1.8. 0 of its 3 modeled counties are predicted at or above the EPA action level of 4 pCi/L, 0 are in the 2-4 "consider fixing" range and 3 are below 2. 0% of Delaware ZIP codes are predicted at 4 or higher.
- Which Delaware county has the highest radon?
- Sussex County has the highest predicted basement average in Delaware at 1.4 pCi/L (EPA Zone 3). The lowest is New Castle County at 1.3 pCi/L. These are modeled area averages; individual homes in any county can test far higher.
- How many EPA Zone 1 counties are in Delaware?
- 0 of Delaware's 3 counties (0%) are EPA Zone 1 (highest potential), 1 are Zone 2 and 2 are Zone 3. The EPA zone map dates from 1993; the predicted values on this page come from a 2001-2021 model built on millions of actual tests, so the two can disagree for a given county.
- Should I test for radon in Delaware?
- Yes. Even though Delaware's predicted average is below 2 pCi/L, the EPA recommends every home be tested - radon varies house to house, and 0% of Delaware ZIP codes are still predicted at 2 pCi/L or higher.
Delaware radon program
Many states offer free or discounted test kits and keep lists of certified mitigators. Find the Delaware radon office through the EPA state radon contacts page. Then read how to test and what mitigation costs.