Pennsylvania · county radon data
Radon in Bucks County, Pennsylvania
27.5% of the 9,078 home radon tests on record here reached the EPA action level — toward the lower end of the state's tested counties, ranked #63 of 67 tested Pennsylvania counties.
What the numbers say
Bucks County sits 21.5 points below the Pennsylvania median (49% of tests over the limit across the state's counties). The median reading among its 9,078 reported tests was 2.1 pCi/L — and the single highest test on record reached 1398.9 pCi/L, more than 349× the action level. EPA maps place the county in Radon Zone 1 — its highest-potential category, where average indoor screening levels are predicted above 4 pCi/L.
Why: the ground under Bucks County
Sits on or beside the Reading Prong — a belt of uranium-bearing Precambrian granite and gneiss that produces some of the highest indoor radon readings in the United States. This is the geology behind the famous 1984 Stanley Watras case in Berks County (a home near Boyertown measured extreme radon), the discovery that launched America's radon programs. Fractured crystalline rock and thin soils let radon move efficiently into basements.
Geology sources: USGS OFR 93-292-C · PA DEP Radon Division · Watras/Boyertown 1984 (PMC4629742).
The housing stock factor
The median Bucks County home dates to 1975 — decades before radon-resistant new construction entered building codes. With 647,461 residents largely housed in that older stock, testing is the only way any individual household knows where it stands.
Radon by ZIP in Bucks County
Pennsylvania is one of the few states publishing actual test results at ZIP level (PA DEP residential data, 1986–2026) — county averages hide a lot; this doesn't.
| ZIP | Place | Tests | % ≥ 4 pCi/L | Max |
|---|---|---|---|---|
| 18081 | Springtown | 143 | 55.2% | 271.9 |
| 18920 | Erwinna | 310 | 49.7% | 61.4 |
| 18077 | Riegelsville | 830 | 45.5% | 240.6 |
| 18932 | Line Lexington | 141 | 45.4% | 39.6 |
| 18913 | Carversville | 219 | 45.2% | 502 |
| 18930 | Kintnersville | 612 | 40.7% | 110.6 |
| 18950 | Point Pleasant | 227 | 40.5% | 32.57 |
| 18923 | Fountainville | 423 | 38.5% | 39 |
| 18977 | Washington Crossing | 3,944 | 38.1% | 220.9 |
| 18942 | Ottsville | 874 | 37.8% | 47.1 |
| 18927 | Hilltown | 196 | 36.7% | 33.5 |
| 18954 | Richboro | 4,872 | 34.6% | 293 |
| 18912 | Buckingham | 836 | 33.3% | 109.7 |
| 18901 | Doylestown | 20,051 | 32.9% | 575.6 |
| 18925 | Furlong | 3,312 | 32.7% | 183.2 |
| 18914 | Chalfont | 95 | 32.6% | 48.2 |
| 18938 | New Hope | 9,233 | 32.3% | 428.3 |
| 18933 | Lumberville | 168 | 31.5% | 358.1 |
| 18980 | Wycombe | 164 | 30.5% | 40.9 |
| 18951 | Quakertown | 7,628 | 30.3% | 549.5 |
| 18947 | Pipersville | 2,466 | 29.5% | 421 |
| 18921 | Ferndale | 38 | 28.9% | 21.4 |
| 18902 | Doylestown | 6,052 | 28.8% | 1000 |
| 18972 | Upper Black Eddy | 850 | 28.8% | 183 |
| 18944 | Perkasie | 7,442 | 28.1% | 396.6 |
| 18946 | Pineville | 74 | 27% | 23.2 |
| 18976 | Warrington | 6,682 | 25.9% | 2107.3 |
| 18960 | Sellersville | 3,183 | 25% | 364.1 |
| 18962 | Silverdale | 92 | 25% | 26.1 |
| 19053 | Feasterville Trevose | 6,298 | 24.9% | 221.9 |
| 18955 | Richlandtown | 301 | 24.6% | 96.9 |
| 18966 | Southampton | 15,085 | 24.6% | 508 |
| 18974 | Warminster | 10,140 | 23.6% | 284.3 |
| 18940 | Newtown | 19,453 | 22.4% | 162.3 |
| 18917 | Dublin | 512 | 22.1% | 113.4 |
| 18929 | Jamison | 4,193 | 21.1% | 182.4 |
| 18970 | Trumbauersville | 131 | 20.6% | 18.8 |
| 19067 | Morrisville | 25,226 | 20.5% | 351.5 |
| 19030 | Fairless Hills | 1,953 | 20.3% | 30.5 |
| 19047 | Langhorne | 36 | 19.4% | 11.2 |
| 19021 | Croydon | 1,311 | 19% | 35.9 |
| 19056 | Levittown | 1,266 | 11.3% | 16 |
| 19007 | Bristol | 2,922 | 8.4% | 29.6 |
| 19054 | Levittown | 1,437 | 8% | 802 |
| 19057 | Levittown | 1,324 | 6.7% | 802 |
| 19055 | Levittown | 1,001 | 4.1% | 68.9 |
Bucks County in the Pennsylvania picture
| Bucks County | 27.5% over the limit | 9,078 tests |
| Pennsylvania's highest: Fulton County | 69.7% | 90 tests |
| Pennsylvania county median | 49% | 67 counties ranked |
| Share of all Pennsylvania tests from this county | 5.2% | |
Ranked nearby in Pennsylvania
- Wayne County — #60, 32.5% of 209 tests over the limit
- Erie County — #61, 31.8% of 6,605 tests over the limit
- Chester County — #62, 29.3% of 11,038 tests over the limit
- Montgomery County — #64, 27.2% of 14,749 tests over the limit
- McKean County — #65, 26.4% of 144 tests over the limit
- Delaware County — #66, 21% of 8,601 tests over the limit
(Ranking neighbors — counties adjacent in the Pennsylvania test ranking, not necessarily on the map.)
High test? Fixes and real pricing: the Pennsylvania mitigation cost guide. Every statistic here traces to the methodology (CDC EPHT (labs), 2008–2017; zones: EPA; year built & population: ACS 5-year; ZIP results: PA DEP).
Bucks County radon FAQ
- Is radon high in Bucks County?
- 27.5% of 9,078 home tests reported to the CDC came back at or above the EPA action level of 4 pCi/L — 21.5 points below the Pennsylvania county median of 49%, ranking #63 of 67 tested counties. EPA classifies the county as Zone 1.
- Does an older home in Bucks County mean more radon risk?
- The county's median home was built in 1975 — before radon-resistant construction practices entered building codes in the 1990s, so most of the housing stock has no built-in radon protection. Construction age changes the odds, not the answer: only a test tells you about your house.
- Where do these Bucks County numbers come from?
- 9,078 aggregated home tests in the CDC's Environmental Public Health Tracking dataset (CDC EPHT 2008-2017). Median reading: 2.1 pCi/L; the highest recorded test hit 1398.9 pCi/L. How we handle the data, including its limits, is documented on our methodology page.
- Which ZIP codes in Bucks County test highest?
- In PA DEP's residential results (1986–2026): 18081 (Springtown) — 55.2% of 143 tests over the limit; 18920 (Erwinna) — 49.7% of 310 tests over the limit; 18077 (Riegelsville) — 45.5% of 830 tests over the limit. Full ZIP table below.