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Radon Levels in Lancaster County, Pennsylvania

EPA puts Lancaster County in Zone 1, its highest radon zone, and high results are common there: 43.3% of the 4,398 radon tests reported to CDC (2020) came back at or above 4 pCi/L. Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

How to test this homeFind a certified tester

  • Share at 4+ pCi/L

    43.3%

    13.0 pts above PA

    Lancaster
    43.3%
    PA
    30.3%

    4,398 tests, 2020

  • Median result

    3.0pCi/L

    Below action level

    Lancaster
    3.0 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2020

  • Tests reported

    4,398

    7th of 63 by tests

    Lancaster
    4,398
    Montgomery
    10,508

    Reported to CDC before any fix, 2020

  • EPA radon zone

    Zone 1

    Highest potential

    1. Zone 1
    2. 2
    3. 3

    1 highest, 3 lowest

    EPA predicts over 4 pCi/L indoors

  • Rank in PA

    21 of 63

    Middle half

    Lancaster
    43.3%
    Perry
    57.7%

    By share, of 63 with 30+ tests

Read a result for Lancaster County

Starts at Lancaster County's median, 3.0 pCi/L

3.0pCi/L

EPA’s own thresholds; the figures are the area’s, never this home’s.

EPA’s reading of 3.0 pCi/L

Between 2 and 4 pCi/L

  1. Under 20 to 1.9 pCi/L
  2. 2 to 4consider a fix
  3. 4 and aboveEPA says fix it

This result is between 2 and 4 pCi/L. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. Lancaster County's median reported result, 2020.

Interpret this readingWhat a fix costs

The data

Lancaster County, At a glance

Lancaster County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Lancaster County in and predicts an average indoor of greater than 4 pCi/L (greater than 150 Bq/m³) across the county. That is one forecast for the whole county, not a reading of any address in it; homes above EPA's turn up in all three zones.

USGS geologic potential: High across 100% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Lancaster County, 2020

Share of reported tests at or above 4 pCi/L, by year, Lancaster County
Share of reported tests at or above 4 pCi/L, by year, Lancaster County
YearShare of reported tests at or above 4 pCi/L
201447.8%
201549.9%
201647.9%
201748.3%
201843.9%
201942.7%
202043.3%

2020: 43.3%. Across these years the share ran from 42.7% to 49.9%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

These are the 4,398 tests reported to CDC for Lancaster County over 2020, many from homes being sold or already suspected of a problem: they describe the county's reported tests, not this house.

Measured: CDC tracking data. Figure above: 2020. Measured data period: 2005 to 2020 (every CDC figure on file).

How to read these figures

Lancaster County, Compared

Lancaster County radon figures, compared

Calculated by Radon411

In Lancaster County, about 4 in 10 reported tests in 2020 (1,903 of 4,398) were at or above EPA's action level. Against the national pool of 25.5%, the gap is 17.8 points higher. Across 67 Pennsylvania counties pooled together, 30.3% of tests reached that level, so Lancaster County runs 13.0 points above its state.

Of 5 neighbours with a figure, 2 reported a larger share at or above 4 pCi/L and 3 a smaller one; the spread is 24.0% (Chester County) to 54.2% (Lebanon County). By share, Lancaster County is 21st of 63 Pennsylvania counties with 30 or more tests for the same period.

Year by year, 2014 opened at 47.8% and 2020 closed at 43.3% (down 4.5 points), with 2015 the high at 49.9%. Half the tests came in under 3.0 pCi/L and half over it; the single highest reached 594.0 pCi/L. Below the action level, 1,743 tests (39.6%) came in under 2 pCi/L, against 44.3% statewide, and 752 tests (17.1%) fell between 2 and 4, against 25.4% statewide.

Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 43.3% share point the same way here. USGS geology rates 100% of the county's land high radon potential.

The busiest year on file was 2015, with 5,314 tests reported; the quietest, 2014, had 3,644.

Share of reported tests at or above 4 pCi/L by year, Lancaster County against Pennsylvania2014 to 2020, years with 30 or more tests: Lancaster County 47.8% to 43.3%, the state's pooled share 30.3% in 2020.
Lancaster CountyPennsylvania, pooled
Share of reported tests at or above 4 pCi/L by year, Lancaster County against Pennsylvania: data table
YearTestsLancaster County, at or above 4 pCi/LPennsylvania, pooled
20143,64447.8%36.1%
20155,31449.9%37.8%
20165,02747.9%34.4%
20174,93248.3%35.1%
20183,77643.9%30.5%
20194,01142.7%31.4%
20204,39843.3%30.3%
Lancaster County against Pennsylvania, the United States and nearby counties, 2020
AreaTestsAt or above 4 pCi/LMedianDifference from Lancaster County
Lancaster County4,39843.3%3.0 pCi/LThis county
Pennsylvania, pooled67 counties, pooled93,66930.3%Not pooled−13.0 points
United States, pooled915 counties, pooled405,35525.5%Not pooled−17.8 points
Perry Countyhighest in the state18957.7%4.9 pCi/L+14.4 points
Philadelphia Countylowest in the state8,44210.6%1.7 pCi/L−32.7 points
Lebanon County, PAborders it1,10254.2%4.8 pCi/L+10.9 points
York County, PAborders it3,67946.8%3.6 pCi/L+3.5 points
Berks County, PAborders it2,63239.6%2.9 pCi/L−3.7 points
Dauphin County, PAborders it2,98636.9%2.0 pCi/L−6.4 points
Chester County, PAborders it6,77024.0%2.0 pCi/L−19.3 points
Where Lancaster County's reported results fell, 2020, beside Pennsylvania and the United States
ResultLancaster County testsLancaster County sharePennsylvania shareU.S. shareAgainst Pennsylvania
Under 2 pCi/L1,74339.6%44.3%51.6%−4.7 points
2 to 4 pCi/L75217.1%25.4%22.9%−8.3 points
4 pCi/L and above1,90343.3%30.3%25.5%+13.0 points
Lancaster County ranked among the 63 Pennsylvania counties with 30 or more tests, by share at or above 4 pCi/L, 2020
CountyRankTestsAt or above 4 pCi/LMedian
Union County16 of 6318244.5%3.3 pCi/L
Indiana County17 of 6322844.3%3.6 pCi/L
Somerset County18 of 6312643.7%3.7 pCi/L
Cumberland County19 of 632,95043.6%3.1 pCi/L
Bradford County20 of 6328643.4%3.4 pCi/L
Lancaster County21 of 634,39843.3%3.0 pCi/L
Franklin County22 of 631,05942.6%3.1 pCi/L
Snyder County23 of 639942.4%2.8 pCi/L
Beaver County24 of 6386842.4%3.2 pCi/L
Butler County25 of 631,49242.3%3.3 pCi/L
Blair County26 of 6342442.0%3.2 pCi/L
Lancaster County radon tests by year, against Pennsylvania's pooled share
YearTestsAt or above 4 pCi/LMedianHighestPennsylvania, pooledChange from the row before
20204,39843.3%3.0 pCi/L594.0 pCi/L30.3%+0.6 points
20194,01142.7%3.0 pCi/L510.0 pCi/L31.4%−1.2 points
20183,77643.9%3.1 pCi/L302.7 pCi/L30.5%−4.4 points
20174,93248.3%3.7 pCi/L302.2 pCi/L35.1%+0.4 points
20165,02747.9%3.6 pCi/L967.0 pCi/L34.4%−2.0 points
20155,31449.9%3.9 pCi/L430.2 pCi/L37.8%+2.1 points
20143,64447.8%3.6 pCi/L294.8 pCi/L36.1%First on file

Pooled shares: Radon411's sum of CDC's county counts for one period.

Lancaster County, State data

Pennsylvania's own radon test data

Measured

What Pennsylvania's own agencies publish about radon tests in Lancaster County, with their period. These are not CDC's figures and are never added to them.

MeasuredState figures, not CDC's

What Pennsylvania DEP reports for the ZIP codes in Lancaster County

Pennsylvania DEP publishes its figures by ZIP code, not by county. These are the 61 ZIP codes that lie wholly or partly in Lancaster County, each with the state's own figures for it. Period: Period not stated by DEP.

ZIP codes in Lancaster County
ZIP codeWhat the state reports
17022Basement: average 7.5 pCi/L, 4,903 tests; First floor: average 4.6 pCi/L, 404 tests
17073Basement: average 11.7 pCi/L, 559 tests; First floor: average 8.1 pCi/L, 52 tests
17501Basement: average 14.3 pCi/L, 726 tests; First floor: average 6.6 pCi/L, 63 tests
17502Basement: average 8.7 pCi/L, 176 tests; First floor: figures not shown
17504Basement: figures not shown; First floor: figures not shown
17505Basement: average 9.9 pCi/L, 143 tests; First floor: average 7.8 pCi/L, 30 tests
17506Basement: figures not shown; First floor: figures not shown
17507Basement: figures not shown; First floor: figures not shown
17508Basement: average 14.9 pCi/L, 210 tests; First floor: figures not shown
17509Basement: average 14.1 pCi/L, 364 tests; First floor: average 6.5 pCi/L, 59 tests
17512Basement: average 12.4 pCi/L, 1,538 tests; First floor: average 7.2 pCi/L, 168 tests
17516Basement: average 12.6 pCi/L, 624 tests; First floor: average 9.9 pCi/L, 63 tests
17517Basement: average 6.8 pCi/L, 1,621 tests; First floor: average 3.8 pCi/L, 152 tests
17518Basement: average 26.1 pCi/L, 99 tests; First floor: figures not shown
17519Basement: average 9.8 pCi/L, 464 tests; First floor: average 3.0 pCi/L, 38 tests
17520Basement: average 9.8 pCi/L, 1,122 tests; First floor: average 5.5 pCi/L, 193 tests
17522Basement: average 10.5 pCi/L, 4,389 tests; First floor: average 6.1 pCi/L, 474 tests
17527Basement: average 16.1 pCi/L, 504 tests; First floor: average 7.7 pCi/L, 48 tests
17529Basement: average 6.2 pCi/L, 235 tests; First floor: average 4.6 pCi/L, 36 tests
17532Basement: average 24.7 pCi/L, 438 tests; First floor: average 15.6 pCi/L, 75 tests
17534Basement: figures not shown
17535Basement: average 11.4 pCi/L, 87 tests; First floor: figures not shown
17536Basement: average 21.0 pCi/L, 338 tests; First floor: average 14.2 pCi/L, 33 tests
17538Basement: average 9.4 pCi/L, 1,803 tests; First floor: average 5.0 pCi/L, 141 tests
17540Basement: average 11.1 pCi/L, 1,333 tests; First floor: average 6.7 pCi/L, 166 tests
17543Basement: average 13.9 pCi/L, 11,600 tests; First floor: average 8.0 pCi/L, 1,228 tests
17545Basement: average 17.7 pCi/L, 3,802 tests; First floor: average 8.7 pCi/L, 417 tests
17547Basement: average 9.5 pCi/L, 1,029 tests; First floor: average 4.3 pCi/L, 98 tests
17550Basement: average 7.9 pCi/L, 92 tests; First floor: figures not shown
17551Basement: average 7.9 pCi/L, 1,631 tests; First floor: average 4.2 pCi/L, 195 tests
17552Basement: average 11.5 pCi/L, 3,271 tests; First floor: average 6.1 pCi/L, 470 tests
17554Basement: average 10.7 pCi/L, 1,080 tests; First floor: average 5.4 pCi/L, 118 tests
17555Basement: average 9.4 pCi/L, 562 tests; First floor: average 5.2 pCi/L, 47 tests
17557Basement: average 8.7 pCi/L, 1,221 tests; First floor: average 7.2 pCi/L, 134 tests
17560Basement: average 20.7 pCi/L, 498 tests; First floor: average 9.2 pCi/L, 38 tests
17562Basement: average 25.4 pCi/L, 217 tests; First floor: average 11.0 pCi/L, 37 tests
17563Basement: average 14.6 pCi/L, 255 tests; First floor: figures not shown
17565Basement: average 24.9 pCi/L, 479 tests; First floor: average 11.9 pCi/L, 72 tests
17566Basement: average 15.5 pCi/L, 1,322 tests; First floor: average 8.7 pCi/L, 97 tests
17568Basement: figures not shown; First floor: figures not shown
17569Basement: average 5.1 pCi/L, 706 tests; First floor: average 4.0 pCi/L, 75 tests
17570Basement: figures not shown; First floor: figures not shown
17572Basement: average 10.1 pCi/L, 228 tests; First floor: figures not shown
17576Basement: average 11.2 pCi/L, 40 tests; First floor: figures not shown
17578Basement: average 6.7 pCi/L, 535 tests; First floor: average 5.6 pCi/L, 36 tests
17579Basement: average 9.5 pCi/L, 955 tests; First floor: average 7.9 pCi/L, 93 tests
17581Basement: average 4.6 pCi/L, 40 tests; First floor: figures not shown
17582Basement: average 9.0 pCi/L, 233 tests; First floor: average 3.1 pCi/L, 41 tests
17584Basement: average 11.1 pCi/L, 1,475 tests; First floor: average 5.9 pCi/L, 217 tests
17601Basement: average 8.7 pCi/L, 14,480 tests; First floor: average 5.7 pCi/L, 1,659 tests
17602Basement: average 6.1 pCi/L, 5,508 tests; First floor: average 3.9 pCi/L, 1,023 tests
17603Basement: average 6.1 pCi/L, 8,203 tests; First floor: average 3.7 pCi/L, 1,023 tests
17606Basement: figures not shown; First floor: figures not shown
19310Basement: average 10.8 pCi/L, 447 tests; First floor: average 5.1 pCi/L, 57 tests
19344Basement: average 5.6 pCi/L, 1,706 tests; First floor: average 2.8 pCi/L, 188 tests
19362Basement: average 8.0 pCi/L, 592 tests; First floor: average 3.5 pCi/L, 63 tests
19363Basement: average 4.9 pCi/L, 2,485 tests; First floor: average 2.8 pCi/L, 237 tests
19501Basement: average 3.2 pCi/L, 62 tests; First floor: figures not shown
19540Basement: average 7.5 pCi/L, 1,625 tests; First floor: average 5.2 pCi/L, 165 tests
19543Basement: average 6.8 pCi/L, 1,298 tests; First floor: average 4.9 pCi/L, 70 tests
19551Basement: average 19.1 pCi/L, 954 tests; First floor: average 10.1 pCi/L, 82 tests
  • DEP's report gives the number of tests, the highest result and the average result for each floor tested; it states no period.
  • DEP says the smartest thing to do is to test your home for radon, no matter where you live.
  • A ZIP code that crosses the county line is listed whole; its figures cover all of it.

Measured: Pennsylvania DEP data, Period not stated by DEP.

Lancaster County, Geology

The ground under Lancaster County

Predicted

USGS's geologic map puts all of Lancaster County's mapped land in one class: high radon potential. The map puts 64.7% of Lancaster County in the area it calls Piedmiont Upland and 20.8% in Piedmont Lowland, with one smaller area beside them. USGS gives both a radon index of 14, in the high band (12 to 17).

USGS's geologic areas under Lancaster County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Piedmiont UplandGranitic gneiss, graphitic gneiss, quartz monzonite, quartz monzonite gneiss, granodiorite, and granodiorite gneiss.High1464.7%
Piedmont LowlandMica schist, phyllite, hornblende gneiss, and marble.High1420.8%
Newark BasinGray shale and fluvial sandstone.High1214.1%

Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.

Lancaster County beside the ground around it

Lancaster County has more high-potential ground than Pennsylvania as a whole: 100% of its land against 70.4%. Of the 7 counties that border it, none has as large a share of high-potential ground; Berks County comes nearest at 100%.

Share of land by USGS radon potential: Lancaster County, the 7 counties bordering it and Pennsylvania
AreaEPA zoneLow potentialModerate potentialHigh potential
Lancaster CountyZone 1NoneNone100%
Chester CountyZone 1None0.1%99.9%
York CountyZone 10.7%None99.2%
Lebanon CountyZone 1NoneNone100%
Berks CountyZone 1NoneNone100%
Harford County, MDZone 1None26.7%70.2%
Dauphin CountyZone 1NoneNone100%
Cecil County, MDZone 220.0%35.4%38.0%
Pennsylvania67 counties, pooled by land areaVaries0.7%28.9%70.4%

The map rates the ground, not the air in any home.

Local help

Lancaster County, Local resources

Radon testing and mitigation in Lancaster County

Listed radon businesses with an address in Lancaster County:

Listed radon professionals by town: Lancaster, Akron

What Pennsylvania's program says
Phone
800-237-2366
Licensing of radon professionals
The Radon Certification Act requires DEP to establish by regulation, a certification program for persons conducting radon gas and radon progeny testing, laboratory analysis and mitigation of radon contamination in buildings.

What it means

Lancaster County, Questions

Questions about radon in Lancaster County

Are radon levels high in Lancaster County?

In 2020, 43.3% of the radon tests reported to CDC for Lancaster County, Pennsylvania were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.0 pCi/L. Of 63 Pennsylvania counties with 30 or more tests for the same period, 20 reported a higher share; pooled, the state comes to 30.3%.

Which counties border Lancaster County?

Lancaster County borders 7 counties: Chester County, PA, York County, PA, Lebanon County, PA, Berks County, PA, Harford County, MD, Dauphin County, PA and Cecil County, MD.

Products

Lancaster County, Products

Testing a home in Lancaster County

In Lancaster County, 43.3% of 4,398 tests reported to CDC in 2020 reached 4 pCi/L, against 30.3% pooled across Pennsylvania. In Zone 1 the year-round level in Lancaster County is the one to know: a long-term test (more than 90 days) or a monitor, with a short-term kit for a first answer.

Test kits and monitors3

See every kit and monitor

Lancaster County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Lancaster County

Explore

Lancaster County, Bordering counties

Counties bordering Lancaster County

Calculated by Radon411

Lancaster County, Cities and towns

Cities and towns in Lancaster County

The Census Bureau estimates 563,159 residents in Lancaster County for July 1, 2025, 10,340 more than in 2020 (+1.9%). That works out to 597 people per square mile of land. No town dominates: Lancaster, the largest, has 58,366 residents, 10.4% of the total. CDC's 4,398 reported tests for 2020 work out to 7.8 per 1,000 residents (2025 estimate), close to Pennsylvania's 7.2.

From Lancaster to Christiana, CDC publishes no figure by town: each reads Lancaster County's.

The 12 largest cities and towns in Lancaster County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Lancaster58,366+0.8%10.4%
Ephrata13,647−1.3%2.4%
Elizabethtown11,961+2.6%2.1%
Columbia10,314+1.1%1.8%
Lititz9,689+2.2%1.7%
Millersville9,280+17.6%1.6%
Mount Joy8,319+0.3%1.5%
New Holland5,754−0.6%1.0%
Manheim4,977−1.3%0.9%
East Petersburg4,702+3.1%0.8%
Akron4,093−1.3%0.7%
Denver3,747−1.1%0.7%
  • Strasburg
  • Mountville
  • Marietta
  • Quarryville
  • Adamstown (part)
  • Terre Hill
  • Christiana

19 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. “(part)” marks a place that extends into another county. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025).

Lancaster County, Homes

Homes in Lancaster County

Of Lancaster County's 217,863 homes, 55% are detached houses, against 57% across Pennsylvania; 13% are in buildings of five or more homes. Much of Lancaster County is recent building: 20% of its homes have gone up since 2000 and the middle year built is 1977, against 1965 for Pennsylvania. 70% of occupied homes are lived in by their owner (Pennsylvania: 69%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Lancaster County, Pennsylvania, 2019 to 2023
HomesLancaster CountyPennsylvania
Housing units217,8635,779,663
Detached houses55%57%
In buildings of 5 or more13%13%
Mobile homes4%4%
Built before 196033%45%
Built since 200020%14%
Middle year built19771965
Owner-occupied70%69%

Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.