Radon levels in Pennsylvania: Moderate
The model predicts a population-weighted basement average of 2.3 pCi/L across Pennsylvania's 67 counties - about 1.3× the US average of 1.8 pCi/L. Above-ground floors average 1.5 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.
49 / 67
EPA Zone 1 counties (73%)
17 / 1
Zone 2 / Zone 3 counties
2
counties predicted ≥ 4 pCi/L
2.9%
of ZIP codes predicted ≥ 4 pCi/L
Pennsylvania counties by predicted radon
Sorted highest to lowest predicted basement average. 67 counties.
| County | Predicted basement | Upstairs | Grade | EPA zone | ZIPs |
|---|---|---|---|---|---|
| Lebanon County | 4.8 pCi/L | 2.5 | High | EPA Zone 1 | 9 |
| Centre County | 4.2 pCi/L | 2.3 | High | EPA Zone 1 | 22 |
| Franklin County | 4.0 pCi/L | 2.2 | Moderate | EPA Zone 1 | 18 |
| Cumberland County | 3.9 pCi/L | 2.3 | Moderate | EPA Zone 1 | 14 |
| Snyder County | 3.8 pCi/L | 1.8 | Moderate | EPA Zone 1 | 10 |
| Huntingdon County | 3.7 pCi/L | 1.9 | Moderate | EPA Zone 1 | 23 |
| Perry County | 3.7 pCi/L | 1.9 | Moderate | EPA Zone 1 | 13 |
| Mifflin County | 3.6 pCi/L | 2.2 | Moderate | EPA Zone 1 | 9 |
| Bedford County | 3.6 pCi/L | 1.6 | Moderate | EPA Zone 1 | 20 |
| Juniata County | 3.5 pCi/L | 1.9 | Moderate | EPA Zone 1 | 8 |
| Columbia County | 3.4 pCi/L | 1.8 | Moderate | EPA Zone 1 | 10 |
| Lycoming County | 3.4 pCi/L | 1.7 | Moderate | EPA Zone 1 | 16 |
| Fulton County | 3.4 pCi/L | 1.7 | Moderate | EPA Zone 1 | 10 |
| Clinton County | 3.4 pCi/L | 1.6 | Moderate | EPA Zone 1 | 8 |
| Dauphin County | 3.4 pCi/L | 2.1 | Moderate | EPA Zone 1 | 24 |
| Carbon County | 3.3 pCi/L | 1.7 | Moderate | EPA Zone 1 | 10 |
| Union County | 3.3 pCi/L | 2.0 | Moderate | EPA Zone 1 | 7 |
| Northumberland County | 3.2 pCi/L | 1.6 | Moderate | EPA Zone 1 | 16 |
| Montour County | 3.2 pCi/L | 1.9 | Moderate | EPA Zone 1 | 2 |
| Armstrong County | 3.1 pCi/L | 1.8 | Moderate | EPA Zone 1 | 16 |
| Lancaster County | 3.1 pCi/L | 2.2 | Moderate | EPA Zone 1 | 45 |
| York County | 3.1 pCi/L | 2.0 | Moderate | EPA Zone 1 | 35 |
| Venango County | 3.1 pCi/L | 1.8 | Moderate | EPA Zone 1 | 12 |
| Jefferson County | 3.1 pCi/L | 1.6 | Moderate | EPA Zone 2 | 18 |
| Clearfield County | 3.1 pCi/L | 1.7 | Moderate | EPA Zone 1 | 33 |
| Indiana County | 3.0 pCi/L | 1.6 | Moderate | EPA Zone 1 | 25 |
| Butler County | 3.0 pCi/L | 1.9 | Moderate | EPA Zone 1 | 26 |
| Schuylkill County | 3.0 pCi/L | 1.7 | Moderate | EPA Zone 1 | 36 |
| Cameron County | 3.0 pCi/L | 1.5 | Moderate | EPA Zone 1 | 3 |
| Clarion County | 2.9 pCi/L | 1.8 | Moderate | EPA Zone 1 | 18 |
| Berks County | 2.8 pCi/L | 1.8 | Moderate | EPA Zone 1 | 39 |
| Blair County | 2.8 pCi/L | 1.5 | Moderate | EPA Zone 1 | 11 |
| Beaver County | 2.8 pCi/L | 1.8 | Moderate | EPA Zone 1 | 18 |
| Bradford County | 2.8 pCi/L | 1.6 | Moderate | EPA Zone 1 | 21 |
| Adams County | 2.7 pCi/L | 1.7 | Moderate | EPA Zone 1 | 11 |
| Monroe County | 2.6 pCi/L | 1.5 | Moderate | EPA Zone 1 | 25 |
| Tioga County | 2.6 pCi/L | 1.6 | Moderate | EPA Zone 1 | 20 |
| Wyoming County | 2.6 pCi/L | 1.6 | Moderate | EPA Zone 1 | 5 |
| Elk County | 2.6 pCi/L | 1.2 | Moderate | EPA Zone 2 | 10 |
| Northampton County | 2.6 pCi/L | 1.9 | Moderate | EPA Zone 1 | 17 |
| Sullivan County | 2.6 pCi/L | 1.5 | Moderate | EPA Zone 1 | 7 |
| Crawford County | 2.6 pCi/L | 1.4 | Moderate | EPA Zone 2 | 17 |
| Potter County | 2.6 pCi/L | 1.4 | Moderate | EPA Zone 2 | 12 |
| Lehigh County | 2.5 pCi/L | 1.7 | Moderate | EPA Zone 1 | 24 |
| Fayette County | 2.5 pCi/L | 1.4 | Moderate | EPA Zone 2 | 35 |
| Forest County | 2.5 pCi/L | 1.3 | Moderate | EPA Zone 2 | 5 |
| Greene County | 2.5 pCi/L | 1.5 | Moderate | EPA Zone 2 | 18 |
| Susquehanna County | 2.4 pCi/L | 1.5 | Moderate | EPA Zone 1 | 22 |
| Lawrence County | 2.4 pCi/L | 1.4 | Moderate | EPA Zone 2 | 11 |
| Somerset County | 2.4 pCi/L | 1.3 | Moderate | EPA Zone 2 | 25 |
| Warren County | 2.4 pCi/L | 1.2 | Moderate | EPA Zone 2 | 13 |
| Westmoreland County | 2.4 pCi/L | 1.6 | Moderate | EPA Zone 1 | 52 |
| Washington County | 2.4 pCi/L | 1.6 | Moderate | EPA Zone 2 | 38 |
| Cambria County | 2.3 pCi/L | 1.2 | Moderate | EPA Zone 2 | 34 |
| Allegheny County | 2.2 pCi/L | 1.6 | Moderate | EPA Zone 1 | 89 |
| Mercer County | 2.2 pCi/L | 1.3 | Moderate | EPA Zone 2 | 17 |
| McKean County | 2.1 pCi/L | 1.1 | Moderate | EPA Zone 2 | 16 |
| Luzerne County | 2.1 pCi/L | 1.4 | Moderate | EPA Zone 1 | 32 |
| Pike County | 2.1 pCi/L | 1.3 | Moderate | EPA Zone 2 | 13 |
| Lackawanna County | 1.9 pCi/L | 1.3 | Low | EPA Zone 1 | 22 |
| Wayne County | 1.9 pCi/L | 1.2 | Low | EPA Zone 2 | 19 |
| Erie County | 1.8 pCi/L | 1.2 | Low | EPA Zone 2 | 26 |
| Chester County | 1.7 pCi/L | 1.4 | Low | EPA Zone 1 | 30 |
| Bucks County | 1.5 pCi/L | 1.1 | Low | EPA Zone 1 | 37 |
| Montgomery County | 1.5 pCi/L | 1.1 | Low | EPA Zone 1 | 52 |
| Delaware County | 1.2 pCi/L | 0.9 | Low | EPA Zone 1 | 36 |
| Philadelphia County | 0.9 pCi/L | 0.7 | Low | EPA Zone 3 | 46 |
Pennsylvania radon questions
- Is radon high in Pennsylvania?
- Pennsylvania's population-weighted predicted basement average is 2.3 pCi/L, about 1.3× the US average of 1.8. 2 of its 67 modeled counties are predicted at or above the EPA action level of 4 pCi/L, 57 are in the 2-4 "consider fixing" range and 8 are below 2. 2.9% of Pennsylvania ZIP codes are predicted at 4 or higher.
- Which Pennsylvania county has the highest radon?
- Lebanon County has the highest predicted basement average in Pennsylvania at 4.8 pCi/L (EPA Zone 1). The lowest is Philadelphia County at 0.9 pCi/L. These are modeled area averages; individual homes in any county can test far higher.
- How many EPA Zone 1 counties are in Pennsylvania?
- 49 of Pennsylvania's 67 counties (73%) are EPA Zone 1 (highest potential), 17 are Zone 2 and 1 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 Pennsylvania?
- Yes - with some urgency. Pennsylvania's predicted average is in the moderate range, and 79% of its ZIP codes are predicted at 2 pCi/L or higher. A short-term charcoal kit or a continuous digital monitor will tell you your actual level within days.
Pennsylvania radon program
Many states offer free or discounted test kits and keep lists of certified mitigators. Find the Pennsylvania radon office through the EPA state radon contacts page. Then read how to test and what mitigation costs.