York County radon levels by ZIP code
98,845 DEP test results, ZIP by ZIP. About half of York County tests reach the EPA action level.
Every radon test that a DEP-certified tester carries out or a certified laboratory analyses in Pennsylvania has to be reported to the Department of Environmental Protection. DEP publishes those results, and this page works them out for York County, ZIP code by ZIP code: 98,845 test results from 1986 to 2026.
What the numbers show
- About half of York County tests reach the action level. 52.5% of results are at or above 4.0 pCi/L, against 33.7% for Pennsylvania as a whole. 26.8% are 10 pCi/L or more, and 13.1% are 20 or more.
- York has the highest share of the five south-central counties, just ahead of Lancaster and well ahead of Adams.
- The south and east of the county run highest. Among ZIPs with at least 100 tests, the highest shares are Brogue (17309, 74.5%), Airville (17302, 67.6%), Windsor (17366, 67.1%), New Park (17352, 66.5%), Dallastown (17313, 65.7%), Felton (17322, 65.2%).
- The north and west run lower, but not low. The lowest shares are Wellsville (17365, 33.6%), York Haven (17370, 40.8%), Manchester (17345, 41.0%), Etters (17319, 42.1%), Dover (17315, 44.2%). Even there, around a third or more of tests reach 4.0.
- Basements read about twice as high as the floors above. Basement tests have a median of 4.9 pCi/L and 56.5% reach 4.0; first-floor tests have a median of 2.1 and 33.5%.
- Recent tests come in lower. Since 2016 the median is 3.5 pCi/L and 46.6% reach 4.0, down from the 1996–2005 peak. The data cannot say why; retests after mitigation and newer houses built with passive systems are both in the mix.
Radon by ZIP code
Every ZIP with at least 30 York County test results, highest share first. Median and highest are in pCi/L; the ≥ columns are the share of tests at or above 4.0 and 2.0 pCi/L. Click a column heading to sort. An asterisk marks ZIPs with fewer than 100 tests, where a handful of results can move the percentages a lot.
| ZIP | Town | Tests | Median | ≥ 4.0 | ≥ 2.0 | Highest |
|---|---|---|---|---|---|---|
| 17355 | Railroad | 37 * | 9.0 | 83.8% | 89.2% | 24.6 |
| 17309 | Brogue | 216 | 9.6 | 74.5% | 86.6% | 278.3 |
| 17342 | Loganville | 42 * | 8.2 | 71.4% | 78.6% | 123.8 |
| 17371 | York New Salem | 36 * | 6.4 | 69.4% | 86.1% | 42.8 |
| 17302 | Airville | 417 | 7.0 | 67.6% | 82.0% | 772.5 |
| 17366 | Windsor | 864 | 8.8 | 67.1% | 81.5% | 237.5 |
| 17352 | New Park | 161 | 7.0 | 66.5% | 80.7% | 236.8 |
| 17313 | Dallastown | 2,420 | 7.6 | 65.7% | 79.9% | 292.0 |
| 17322 | Felton | 952 | 7.6 | 65.2% | 79.9% | 445.4 |
| 17321 | Fawn Grove | 460 | 6.8 | 64.8% | 77.2% | 196.0 |
| 17363 | Stewartstown | 2,814 | 6.9 | 63.8% | 75.8% | 333.2 |
| 17360 | Seven Valleys | 1,543 | 7.5 | 63.4% | 76.2% | 317.7 |
| 17407 | Jacobus | 714 | 6.5 | 62.2% | 77.6% | 383.0 |
| 17329 | Glenville | 613 | 6.9 | 61.2% | 72.8% | 454.9 |
| 17356 | Red Lion | 5,341 | 6.1 | 60.9% | 73.8% | 487.5 |
| 17327 | Glen Rock | 1,797 | 5.9 | 60.8% | 78.5% | 397.4 |
| 17362 | Spring Grove | 3,003 | 5.8 | 58.6% | 72.6% | 672.9 |
| 17347 | Mount Wolf | 1,258 | 5.1 | 58.1% | 75.0% | 304.4 |
| 17314 | Delta | 972 | 5.1 | 57.4% | 74.0% | 521.8 |
| 17368 | Wrightsville | 1,351 | 5.2 | 56.9% | 73.0% | 1040.9 |
| 17403 | York | 8,348 | 4.7 | 55.2% | 74.7% | 437.3 |
| 17402 | York | 10,722 | 4.6 | 54.6% | 73.3% | 260.0 |
| 17406 | York | 4,025 | 4.3 | 52.6% | 71.4% | 409.5 |
| 17349 | New Freedom | 2,730 | 4.3 | 52.0% | 70.7% | 239.6 |
| 17361 | Shrewsbury | 2,117 | 4.3 | 52.0% | 72.2% | 205.6 |
| 17364 | Thomasville | 436 | 4.1 | 51.8% | 72.0% | 121.9 |
| 17404 | York | 8,196 | 4.0 | 50.7% | 72.0% | 534.0 |
| 17408 | York | 3,880 | 4.0 | 50.1% | 68.6% | 203.1 |
| 17019 | Dillsburg | 5,858 | 3.7 | 47.4% | 67.0% | 228.0 |
| 17331 | Hanover | 11,820 | 3.6 | 47.0% | 67.9% | 1259.7 |
| 17339 | Lewisberry | 2,150 | 3.4 | 44.9% | 66.9% | 382.0 |
| 17315 | Dover | 4,041 | 3.3 | 44.2% | 67.2% | 547.0 |
| 17319 | Etters | 2,905 | 3.2 | 42.1% | 64.4% | 343.4 |
| 17345 | Manchester | 983 | 3.2 | 41.0% | 68.7% | 695.6 |
| 17370 | York Haven | 1,034 | 3.0 | 40.8% | 65.0% | 176.0 |
| 17317 | East Prospect | 95 * | 1.7 | 33.7% | 45.3% | 75.8 |
| 17365 | Wellsville | 440 | 2.8 | 33.6% | 63.4% | 92.0 |
| 17401 | York | 605 | 1.8 | 22.1% | 47.1% | 24.1 |
| 17405 | York | 39 * | 1.6 | 20.5% | 38.5% | 24.9 |
Five ZIPs cross the county line and have most of their tests in Adams or Cumberland County: 17011 Camp Hill, 17301 Abbottstown, 17316 East Berlin, 17070 New Cumberland, 17055 Mechanicsburg. They are left out of the table; their York County rows are in the download.
Downtown York (17401) has the lowest share in the county, 22.1% of 605 tests. Only about half of its tests were taken in a basement, against four in five county-wide, which pulls its numbers down. Even its basement tests reach 4.0 only 34.1% of the time, against 56.5% county-wide.
How York compares with its neighbours
All DEP results for each county, 1986 to 2026.
| County | Tests | Median pCi/L | At or above 4.0 | At or above 4.0, tests since 2016 |
|---|---|---|---|---|
| York | 98,845 | 4.3 | 52.5% | 46.6% |
| Lancaster | 134,696 | 4.1 | 51.3% | 43.2% |
| Cumberland | 103,102 | 3.9 | 49.9% | 39.5% |
| Dauphin | 96,399 | 3.0 | 43.3% | 33.5% |
| Adams | 22,270 | 2.8 | 38.2% | 38.9% |
| Pennsylvania | 3,334,280 | 2.5 | 33.7% | 30.3% |
The EPA maps all five counties as Zone 1, meaning a predicted average screening level above 4 pCi/L.
Over time
| Test years | Tests | Median pCi/L | At or above 4.0 |
|---|---|---|---|
| 1986–1995 | 6,932 | 4.2 | 52.5% |
| 1996–2005 | 19,482 | 5.2 | 58.3% |
| 2006–2015 | 35,093 | 4.8 | 55.7% |
| 2016–2026 | 37,338 | 3.5 | 46.6% |
Basement or upstairs
| Floor tested | Tests | Median pCi/L | At or above 4.0 |
|---|---|---|---|
| Basement | 81,840 | 4.9 | 56.5% |
| First floor | 10,682 | 2.1 | 33.5% |
| Slab on grade | 2,109 | 2.5 | 37.2% |
The EPA action level applies to the lowest lived-in level of the house. That is why most tests are taken in the basement: if anyone uses it, the basement number is the one that counts.
What mitigation does to the number
DEP's separate mitigation records for York County hold 8,831 readings taken before a system was installed and 12,298 taken after. The median before is 13.0 pCi/L; the median after is 1.0 pCi/L, and 2.1% of after-tests are still at or above 4.0. See what a system costs in York County.
What the data can and cannot tell you
- These are tests, not a random survey of homes. People test when they buy or sell, when a neighbour finds radon, or after mitigation, so the houses tested are not a random sample.
- Most are short-term, closed-house tests, mostly in basements, which read higher than a year-long average of the living space.
- Some houses are counted more than once, and DEP does not record whether a test was before or after mitigation.
- A ZIP average says nothing certain about your house. Houses on the same street can read very differently. The only way to know is to test your own home.
- The one random survey agrees. The EPA and state residential survey of 1987–88 measured 68 randomly chosen York County homes on the lowest level: median 6.6 pCi/L, with 68% over 4 pCi/L.
Why York County runs high
The USGS geologic assessment of Pennsylvania links high uranium readings to the Wissahickon Formation phyllite in central York County and lists the Wissahickon and Peters Creek schists as known radon sources. It rates the Gettysburg basin in the north of the county as low to locally moderate, which matches the lower shares in Dover, Etters, York Haven and Wellsville. More on the rock and on radon in well water: radon in York County.
If your test is high
- Confirm it. A second short-term test, or a long-term test if you are not in a hurry. For a house sale, the 48-hour test by a certified tester is the standard.
- Fix it at 4.0 or above; consider it between 2.0 and 4.0. That is the EPA guidance.
- Hire a DEP-certified mitigator. In Pennsylvania anyone who tests or mitigates radon for pay must be certified by DEP. Browse DEP-certified companies serving York County.
Sources and method
- Test results: PA DEP, Radon Test Results, September 1986 – Current, PA Open Data, public domain. Rows updated 2026-07-13; York County test end dates 1986-11-03 to 2026-07-03. Results are reported by DEP-certified testers and laboratories under 25 Pa. Code §240.303.
- Mitigation records: PA DEP, Radon Mitigation System Year 1987 – Current, PA Open Data, public domain.
- DEP's own ZIP report: Radon Test Data by Zip Code, short-term closed-house tests, January 1990 to December 2025. Its averages are close to ours but not identical, because it covers whole ZIPs and a narrower set of tests.
- EPA radon zones: EPA Map of Radon Zones, Pennsylvania.
- Geology and the 1987–88 survey: USGS Open-File Report 93-292-C, Preliminary Geologic Radon Potential Assessment of Pennsylvania, 1993.
- Method: York County records (county name York) grouped by the first five digits of the ZIP; ZIPs with fewer than 30 results left out, as DEP does. Medians and shares are over all test types and floors. "Town" is the most common postal town in each ZIP's records, not a township. Negative and non-numeric readings were dropped.
Download the data: york-county-radon-by-zip.csv, every ZIP above plus the border ZIPs, with basement-only figures and test date ranges. Free to reuse with credit to Radon Mitigation in York and a link to this page; the underlying DEP data is public domain.
Cite this page: Radon Mitigation in York, "York County radon levels by ZIP code", radonmitigationinyork.com/guides/york-county-radon-levels-by-zip-code, from PA DEP radon test records (1986–2026), updated 2026-09-30.
Last updated 2026-09-30. General information for the York area, not professional advice; confirm specifics with a qualified contractor or your insurer.