York County is EPA Radon Zone 1, and PA DEP’s own records put the county among the worst radon areas in Pennsylvania. Here are the numbers by ZIP code and by community — and what each one means for your house.
The PA DEP open-data record shows 98,845 radon tests in York County, with 52.5% of all county tests — and roughly 56% of basement tests specifically — at or above the EPA action level of 4.0 pCi/L. Statewide, about 40% of tested Pennsylvania homes exceed 4.0; the county’s carbonate and slate geology pushes York well past that (PA Geological Survey County Report 67 maps the belts).
DEP’s ZIP-level records show basement readings running 7–12 pCi/L across the York ZIPs:
| York ZIP | Housing on that ground | Typical basement test (pCi/L) |
|---|---|---|
| 17401 – Downtown | Historic rowhomes on unventilated stone foundations | 10.6 average — frequently above 4.0 |
| 17402 – East | 1950s–1970s ranches; mixed basement types | Frequently above 4.0 |
| 17403 – South | Post-war development on the carbonate belt | Frequently above 4.0 |
| 17404 – West | Older housing near the industrial corridor | 11.8 average — the city’s highest |
| 17406 – Northeast | Newer subdivisions on the shale uplands | Mixed — test anyway |
| 17408 – Northeast | Established suburbs on the shale uplands | Mixed — test anyway |
EPA’s action guideline is 4.0 pCi/L; WHO recommends acting at 2.7 (100 Bq/m³). A confirmed reading between 4 and 8 deserves a second test or a long-term average; anything at 10 or above — common in these ZIPs — moves straight to mitigation planning. Two houses on the same street routinely test 2 vs 20 pCi/L: the house, not the ZIP, sets the final number. The test decides; radon testing explains the protocol.
Whatever your ZIP shows, the fix is the same: sub-slab depressurization, installed in a day by a DEP-certified firm, dropping 80–99% of the reading. If you are shopping: our comparison of York PA radon companies lists every certified firm with review records, and the 2026 cost page prices each system type. Radon mitigation York PA handles diagnostics, written fixed quotes and the post-mitigation retest across all eleven communities above — the contact page starts with your test result.
PA DEP records 7–12 pCi/L typical basement readings across the York ZIPs, with 52.5% of 98,845 county tests above the 4.0 pCi/L action level — roughly 56% for basement tests specifically.
The city’s older cores: 17401 (Downtown, 10.6 average) and 17404 (West York, 11.8 — the highest). Springettsbury readings nearby run 8.9–9.2. Every York County ZIP is EPA Zone 1.
EPA’s tables project about 62 lung cancers per 1,000 people exposed to 4.0 pCi/L over a lifetime; WHO sets its reference at 2.7. No level is zero-risk, and the county’s geology makes 4+ readings the local norm.