Radon in Chester County, Pennsylvania
Chester County, Pennsylvania, is in EPA radon Zone 1: predicted average indoor radon screening level greater than 4 pCi/L (highest potential). Radon laboratories reported 11,038 building tests here for 2008 to 2017: median 2.2 pCi/L, with 29.3% at or above EPA's 4 pCi/L action level (Pennsylvania 41.1%, US 36.5%). Pennsylvania state records have 261,523 test results on file for the county, median 2.2 pCi/L, 29.3% at or above 4 pCi/L.
Radon test results in Chester County
| Test results | Period | Tests | Typical result | 4 pCi/L or more |
|---|---|---|---|---|
| Radon testing laboratories | 2008-2017 | 11,038 | median 2.2 pCi/L | 29.3% |
| Pennsylvania state records, every reported test | 1986 to 2026-07 | 261,523 | median 2.2 pCi/L | 29.3% |
| Pennsylvania, all counties (labs) | 2008-2017 | 173,284 | n/a | 41.1% |
| United States (labs) | 2008-2017 | 1,408,802 | n/a | 36.5% |
Test results describe buildings whose owners chose to test and whose results reached the lab or agency, not a random sample; small counts swing widely. State and US shares are computed from county counts and percents. The laboratory data comes from national radon testing laboratories and supplements EPA's zone map.
Radon levels by ZIP code in Chester County
Pennsylvania state results for the ZIP codes with 10 or more tests reported in Chester County, 1986 to 2026-07.
| ZIP code | Tests | Median | 4 pCi/L or more |
|---|---|---|---|
| 17201 | 24 | 6.2 pCi/L | 66.7% |
| 17527 | 12 | 3.1 pCi/L | 41.7% |
| 19073 | 102 | 1.5 pCi/L | 8.8% |
| 19083 | 26 | 3.5 pCi/L | 42.3% |
| 19087 | 5,292 | 2.1 pCi/L | 25.9% |
| 19301 | 6,595 | 2.8 pCi/L | 40.4% |
| 19310 | 769 | 4.9 pCi/L | 56.4% |
| 19311 | 2,825 | 1.8 pCi/L | 18.7% |
| 19312 | 10,921 | 2.3 pCi/L | 32% |
| 19316 | 31 | 1.6 pCi/L | 16.1% |
| 19317 | 574 | 1.6 pCi/L | 12% |
| 19318 | 41 | 3.2 pCi/L | 39% |
| 19320 | 20,265 | 3.3 pCi/L | 43.7% |
| 19325 | 13 | 1.3 pCi/L | 15.4% |
| 19330 | 1,790 | 3.8 pCi/L | 48.9% |
| 19333 | 5,535 | 2.1 pCi/L | 28.9% |
| 19335 | 33,236 | 2.4 pCi/L | 33.5% |
| 19341 | 9,679 | 1.8 pCi/L | 18.7% |
| 19342 | 111 | 1.8 pCi/L | 21.6% |
| 19343 | 5,036 | 2.6 pCi/L | 33.5% |
| 19344 | 2,834 | 2.4 pCi/L | 33.3% |
| 19346 | 19 | 3.7 pCi/L | 42.1% |
| 19347 | 85 | 1.8 pCi/L | 18.8% |
| 19348 | 11,389 | 2.1 pCi/L | 23.5% |
| 19350 | 5,201 | 1.9 pCi/L | 19.6% |
| 19351 | 16 | 1.9 pCi/L | 6.2% |
| 19352 | 2,769 | 2.1 pCi/L | 23.2% |
| 19353 | 94 | 2.8 pCi/L | 33% |
| 19354 | 35 | 3.9 pCi/L | 48.6% |
| 19355 | 19,698 | 2.4 pCi/L | 33% |
| 19357 | 40 | 2.0 pCi/L | 20% |
| 19358 | 53 | 3.3 pCi/L | 41.5% |
| 19360 | 127 | 2.0 pCi/L | 22.8% |
| 19362 | 856 | 3.6 pCi/L | 46.3% |
| 19363 | 4,172 | 2.8 pCi/L | 35.1% |
| 19365 | 2,765 | 4.3 pCi/L | 52% |
| 19366 | 29 | 3.6 pCi/L | 48.3% |
| 19367 | 45 | 4.6 pCi/L | 62.2% |
| 19369 | 75 | 12.0 pCi/L | 89.3% |
| 19370 | 15 | 1.9 pCi/L | 33.3% |
| 19372 | 1,123 | 2.4 pCi/L | 31.8% |
| 19374 | 76 | 2.7 pCi/L | 28.9% |
| 19375 | 206 | 2.3 pCi/L | 26.2% |
| 19376 | 28 | 5.7 pCi/L | 53.6% |
| 19380 | 32,485 | 1.9 pCi/L | 26.6% |
| 19381 | 28 | 2.2 pCi/L | 35.7% |
| 19382 | 24,736 | 1.6 pCi/L | 16% |
| 19383 | 101 | 1.4 pCi/L | 19.8% |
| 19385 | 56 | 0.5 pCi/L | 0% |
| 19390 | 4,034 | 2.0 pCi/L | 21.6% |
| 19395 | 138 | 1.4 pCi/L | 14.5% |
| 19403 | 36 | 2.4 pCi/L | 33.3% |
| 19406 | 33 | 1.9 pCi/L | 27.3% |
| 19421 | 151 | 2.5 pCi/L | 27.8% |
| 19425 | 11,676 | 2.3 pCi/L | 29.4% |
| 19431 | 16 | 1.3 pCi/L | 0% |
| 19432 | 22 | 2.2 pCi/L | 31.8% |
| 19442 | 407 | 2.8 pCi/L | 35.9% |
| 19457 | 29 | 3.1 pCi/L | 34.5% |
| 19460 | 20,163 | 2.0 pCi/L | 25.2% |
| 19464 | 13 | 2.4 pCi/L | 23.1% |
| 19465 | 5,729 | 2.5 pCi/L | 29.1% |
| 19470 | 41 | 2.3 pCi/L | 19.5% |
| 19475 | 4,250 | 2.4 pCi/L | 30.2% |
| 19480 | 71 | 2.2 pCi/L | 39.4% |
| 19481 | 443 | 2.0 pCi/L | 24.2% |
| 19482 | 28 | 1.6 pCi/L | 21.4% |
| 19520 | 1,987 | 3.0 pCi/L | 40.1% |
| 19543 | 89 | 1.8 pCi/L | 21.3% |
Radon in nearby counties
| County | EPA zone | Lab tests | 4 pCi/L or more |
|---|---|---|---|
| Delaware County, PA | Zone 1 | 8,601 | 21% |
| Montgomery County, PA | Zone 1 | 14,749 | 27.2% |
| Lancaster County, PA | Zone 1 | 8,108 | 55.1% |
| New Castle County, DE | Zone 2 | 9,184 | 17% |
| Cecil County, MD | Zone 2 | 831 | 24.9% |
| Berks County, PA | Zone 1 | 7,522 | 52.6% |
The six counties with the nearest centers.
What to do about radon in Chester County
Test the building. EPA recommends fixing a home at 4 pCi/L or more and considering a fix between 2 and 4 pCi/L, and says there is no known safe level of exposure. The state environmental protection agency runs the state's radon program.
Buying here? The Environmental Records Report lists this county's radon zone and test results with the flood zone, mapped faults, power lines and federal contamination records near the address.
Radon in Chester County: questions
What is the radon level in Chester County?
The median of the 11,038 laboratory tests reported for Chester County (2008 to 2017) was 2.2 pCi/L, and 29.3% of them were at or above 4 pCi/L. Pennsylvania's 261,523 state results have a median of 2.2 pCi/L. These are results of tested buildings; a single home can be far above or below them.
Is Chester County in radon Zone 1?
Yes. EPA's 1993 Map of Radon Zones puts Chester County in Zone 1, the counties with a predicted average indoor radon screening level above 4 pCi/L.
How does radon in Chester County compare with Pennsylvania?
29.3% of laboratory tests in Chester County were at or above 4 pCi/L for 2008 to 2017, against 41.1% across Pennsylvania (173,284 tests) and 36.5% nationally. 49 of Pennsylvania's 67 counties are in Zone 1.
Should I test for radon in Chester County?
Yes. EPA recommends testing every home whatever its zone: "This map should not be used to determine if individual homes need to be tested." Fix the home at 4 pCi/L or more and consider a fix between 2 and 4 pCi/L; EPA says there is no known safe level of radon exposure.
More for Chester County
- Pennsylvania LLC lookupDepartment of State record with the officers listed (initials) and the Philadelphia properties assessed to it.
- Pennsylvania title insurance calculatorTIRBOP Sale Rate owner's policy, simultaneous loan policy and the Homeowner's Policy option.
- Philadelphia closing cost calculatorThe 4.578% realty transfer tax split, title premiums and the seller's net proceeds.
- Chester loan limitsThis year's FHFA conforming, FHA and VA county loan limits for 1 to 4 unit homes, from FHFA's and HUD's official files.
- Chester fair market rentHUD Fair Market Rents for studios to 4 bedrooms, the voucher payment standard range and the change from last year.
- Chester property tax rateEffective property tax rate from Census survey data: median taxes paid against median home value, ranked in the state.
- Environmental records reportSuperfund, hazardous waste, leaking tank and brownfield sites near any Chester address, with distances and a site map. A records search, not a Phase I.
- Superfund sites in PennsylvaniaEvery EPA Superfund site in Pennsylvania with its status, county and a map, refreshed nightly from federal records.
- USDA eligibility map: PennsylvaniaHow much of each Pennsylvania county is in a USDA-eligible rural area, the towns mapped ineligible, and a free address check.
- Opportunity zones in PennsylvaniaEvery designated Opportunity Zone tract in Pennsylvania by county, from the IRS list, and the tracts eligible for the 2027 round.
- Census tract lookupThe census tract of any Chester address with its FFIEC income level and HUD Qualified Census Tract and DDA status.
Other free hazard lookups
- Fault lines near an addressUSGS-mapped earthquake faults within 5 miles, their age and slip rate, and the USGS seismic hazard value.
- Power lines near an addressHigh-voltage transmission lines within 1 mile from federal maps, with voltage and distance.
- Flood zone lookupThe FEMA flood zone mapped at any US address. Not an official flood zone determination.
- Superfund sites near an addressThe nearest EPA Superfund (NPL) sites and their status.
All of these, plus wetlands, FEMA hazard ratings and the federal contamination lists, are in the Environmental Records Report for any US address ($29).
Radon in every Pennsylvania county · Radon map of every state
Data compiled 2026-10-20. County FIPS 42029. County-level screening information, not a radon measurement of any building.