Long-term kit
RL416 long-term radon test kit, lab fee included
- Lab fee included
Method: Alpha track
In home: 90 days to 12 months
Locations and reports
Radon Levels in Butler County, Pennsylvania
EPA puts Butler County in Zone 1, its highest radon zone, and high results are common there: 42.3% of the 1,492 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
Share at 4+ pCi/L
42.3%
12.0 pts above PA
- Butler
- 42.3%
- PA
- 30.3%
1,492 tests, 2020
Median result
3.3pCi/L
Below action level
- Butler
- 3.3 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2020
Tests reported
1,492
16th of 63 by tests
- Butler
- 1,492
- Montgomery
- 10,508
Reported to CDC before any fix, 2020
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Rank in PA
25 of 63
Middle half
- Butler
- 42.3%
- Perry
- 57.7%
By share, of 63 with 30+ tests
Read a result for Butler County
Starts at Butler County's median, 3.3 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 3.3 pCi/L
Between 2 and 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 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. Butler County's median reported result, 2020.
The data
Butler County, At a glance
Butler County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Butler County in
USGS geologic potential: High across 98% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Butler County, 2020
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 47.3% |
| 2015 | 46.9% |
| 2016 | 43.3% |
| 2017 | 45.2% |
| 2018 | 42.2% |
| 2019 | 41.1% |
| 2020 | 42.3% |
2020: 42.3%. Across these years the share ran from 41.1% to 47.3%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 1,492 tests reported to CDC for Butler 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).
Butler County, Compared
Butler County radon figures, compared
Calculated by Radon411In Butler County, about 4 in 10 reported tests in 2020 (631 of 1,492) were at or above EPA's action level. Against the national pool of 25.5%, the gap is 16.8 points higher. Across 67 Pennsylvania counties pooled together, 30.3% of tests reached that level, so Butler County runs 12.0 points above its state.
Of 8 neighbours with a figure, 2 reported a larger share at or above 4 pCi/L and 6 a smaller one; the spread is 30.5% (Allegheny County) to 47.6% (Armstrong County). By share, Butler County is 25th of 63 Pennsylvania counties with 30 or more tests for the same period.
Year by year, 2014 opened at 47.3% and 2020 closed at 42.3% (down 5.0 points), with 2014 the high at 47.3%. Half the tests came in under 3.3 pCi/L and half over it; the single highest reached 301.1 pCi/L. Below the action level, 483 tests (32.4%) came in under 2 pCi/L, against 44.3% statewide, and 378 tests (25.3%) fell between 2 and 4, against 25.4% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 42.3% share point the same way here. USGS geology rates 98% of the county's land high radon potential.
The busiest year on file was 2015, with 1,599 tests reported; the quietest, 2017, had 1,288.
Butler CountyPennsylvania, pooled
42.3% % of tests30.3% % of tests
| Year | Tests | Butler County, at or above 4 pCi/L | Pennsylvania, pooled |
|---|---|---|---|
| 2014 | 1,407 | 47.3% | 36.1% |
| 2015 | 1,599 | 46.9% | 37.8% |
| 2016 | 1,454 | 43.3% | 34.4% |
| 2017 | 1,288 | 45.2% | 35.1% |
| 2018 | 1,359 | 42.2% | 30.5% |
| 2019 | 1,551 | 41.1% | 31.4% |
| 2020 | 1,492 | 42.3% | 30.3% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Butler County, State data
Pennsylvania's own radon test data
MeasuredWhat Pennsylvania's own agencies publish about radon tests in Butler 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 Butler County
Pennsylvania DEP publishes its figures by ZIP code, not by county. These are the 37 ZIP codes that lie wholly or partly in Butler County, each with the state's own figures for it. Period: Period not stated by DEP.
| ZIP code | What the state reports |
|---|---|
| 15044 | Basement: average 7.9 pCi/L, 9,325 tests; First floor: average 6.2 pCi/L, 669 tests |
| 15086 | Basement: average 6.0 pCi/L, 193 tests; First floor: figures not shown |
| 16001 | Basement: average 9.0 pCi/L, 5,477 tests; First floor: average 6.5 pCi/L, 669 tests |
| 16002 | Basement: average 11.5 pCi/L, 1,892 tests; First floor: average 10.1 pCi/L, 69 tests |
| 16020 | Basement: average 12.0 pCi/L, 96 tests; First floor: figures not shown |
| 16022 | Basement: figures not shown; First floor: figures not shown |
| 16023 | Basement: average 10.5 pCi/L, 387 tests; First floor: figures not shown |
| 16024 | Basement: figures not shown; First floor: figures not shown |
| 16025 | Basement: average 14.5 pCi/L, 309 tests; First floor: average 8.3 pCi/L, 31 tests |
| 16027 | Basement: average 6.6 pCi/L, 50 tests; First floor: figures not shown |
| 16029 | Basement: average 9.0 pCi/L, 44 tests; First floor: figures not shown |
| 16030 | Basement: figures not shown; First floor: figures not shown |
| 16033 | Basement: average 9.5 pCi/L, 1,003 tests; First floor: average 4.3 pCi/L, 88 tests |
| 16034 | Basement: average 16.5 pCi/L, 136 tests; First floor: figures not shown |
| 16035 | Basement: figures not shown; First floor: figures not shown |
| 16037 | Basement: average 9.8 pCi/L, 966 tests; First floor: average 6.9 pCi/L, 102 tests |
| 16038 | Basement: average 10.9 pCi/L, 95 tests; First floor: figures not shown |
| 16040 | Basement: figures not shown; First floor: figures not shown |
| 16041 | Basement: average 25.9 pCi/L, 93 tests; First floor: figures not shown |
| 16045 | Basement: average 9.2 pCi/L, 67 tests; First floor: figures not shown |
| 16046 | Basement: average 7.0 pCi/L, 4,895 tests; First floor: average 4.6 pCi/L, 365 tests |
| 16048 | Basement: figures not shown |
| 16049 | Basement: average 14.4 pCi/L, 79 tests; First floor: figures not shown |
| 16050 | Basement: average 11.2 pCi/L, 82 tests; First floor: figures not shown |
| 16051 | Basement: average 11.7 pCi/L, 269 tests; First floor: figures not shown |
| 16052 | Basement: average 15.2 pCi/L, 202 tests; First floor: figures not shown |
| 16053 | Basement: average 10.9 pCi/L, 422 tests; First floor: average 5.6 pCi/L, 46 tests |
| 16055 | Basement: average 9.8 pCi/L, 1,378 tests; First floor: average 5.0 pCi/L, 72 tests |
| 16056 | Basement: average 9.1 pCi/L, 662 tests; First floor: average 4.1 pCi/L, 55 tests |
| 16057 | Basement: average 5.9 pCi/L, 782 tests; First floor: average 2.6 pCi/L, 65 tests |
| 16059 | Basement: average 9.6 pCi/L, 1,665 tests; First floor: average 5.0 pCi/L, 162 tests |
| 16061 | Basement: average 16.3 pCi/L, 175 tests; First floor: figures not shown |
| 16063 | Basement: average 6.9 pCi/L, 1,349 tests; First floor: average 4.0 pCi/L, 97 tests |
| 16066 | Basement: average 5.2 pCi/L, 8,999 tests; First floor: average 3.7 pCi/L, 347 tests |
| 16127 | Basement: average 4.5 pCi/L, 1,205 tests; First floor: average 3.1 pCi/L, 125 tests |
| 16229 | Basement: average 10.9 pCi/L, 458 tests; First floor: average 10.5 pCi/L, 36 tests |
| 16373 | Basement: average 27.0 pCi/L, 155 tests; First floor: average 11.8 pCi/L, 46 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.
Butler County, Geology
The ground under Butler County
PredictedMost of the ground under Butler County is one class on USGS's geologic map: 98.0% of its land is high radon potential, with 2.0% moderate. 98.0% of it lies in the area the map calls Pennsylvanian Rocks of the Pittsburgh Low Plateau, to which USGS gives a radon index of 14, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Pennsylvanian Rocks of the Pittsburgh Low Plateau | Pennsylvanian marine shale, siltstone, sandstone, limestone, and coal. | High | 14 | 98.0% |
| Glaciated Pittsburgh Plateau | Late-Wisconsin till overlying sandstone, shale, limestone, and coal. | Moderate | 11 | 2.0% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Butler County beside the ground around it
Butler County has more high-potential ground than Pennsylvania as a whole: 98.0% of its land against 70.4%. Of the 8 counties that border it, 3 have more high-potential ground, Allegheny County the most at 100%.
The map rates the ground, not the air in any home.
Local help
Butler County, Local resources
Radon testing and mitigation in Butler County
Listed radon businesses with an address in Butler County:
- Radon DivisionRadon Division, run by Department of Environmental Protection, licenses or certifies radon professionals and offers free or discounted test kits, and answers questions about testing and mitigation in Pennsylvania.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
Through an EPA-funded program, hospitals give parents of newborn children a packet of information which includes a coupon for a free radon test kit from the DEP.
- Compare kits
- Professionals in Pennsylvania151 professionals are listed in Pennsylvania.
Listed radon professionals by town: Harmony, Valencia
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
Butler County, Questions
Questions about radon in Butler County
Are radon levels high in Butler County?
In 2020, 42.3% of the radon tests reported to CDC for Butler County, Pennsylvania were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.3 pCi/L. Of 63 Pennsylvania counties with 30 or more tests for the same period, 24 reported a higher share; pooled, the state comes to 30.3%.
Which counties border Butler County?
Butler County borders 8 counties: Lawrence County, Armstrong County, Beaver County, Clarion County, Allegheny County, Mercer County, Venango County and Westmoreland County.
Products
Butler County, Products
Testing a home in Butler County
In Butler County, 42.3% of 1,492 tests reported to CDC in 2020 reached 4 pCi/L, against 30.3% pooled across Pennsylvania. In Zone 1 the year-round level in Butler 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
MonitorAEGTEST
HOUND-1085 palm-sized rechargeable radon detector
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 6 hours
Short-term kit
Radon Short Term Test Kit short-term charcoal radon test kit, lab fee included
- Lab fee included
Method: Charcoal
In home: 2 to 7 days
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Butler County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Butler County
Explore
Butler County, Bordering counties
Counties bordering Butler County
Calculated by Radon411- Radon levels in Armstrong CountyEPA zone 1
47.6%at or above 4 pCi/L
Median 3.7 pCi/L · 187 tests · 5.3 points above Butler County
- Radon levels in Beaver CountyEPA zone 1
42.4%at or above 4 pCi/L
Median 3.2 pCi/L · 868 tests · 0.1 points above Butler County
- Radon levels in Lawrence CountyEPA zone 2
36.0%at or above 4 pCi/L
Median 2.7 pCi/L · 286 tests · 6.3 points below Butler County
- Radon levels in Westmoreland CountyEPA zone 1
34.9%at or above 4 pCi/L
Median 2.6 pCi/L · 1,588 tests · 7.4 points below Butler County
- Radon levels in Venango CountyEPA zone 1
34.1%at or above 4 pCi/L
Median 3.0 pCi/L · 179 tests · 8.2 points below Butler County
- Radon levels in Clarion CountyEPA zone 1
31.8%at or above 4 pCi/L
Median 2.9 pCi/L · 107 tests · 10.5 points below Butler County
- Radon levels in Mercer CountyEPA zone 2
31.4%at or above 4 pCi/L
Median 2.5 pCi/L · 318 tests · 10.9 points below Butler County
- Radon levels in Allegheny CountyEPA zone 1
30.5%at or above 4 pCi/L
Median 2.5 pCi/L · 8,337 tests · 11.8 points below Butler County
Butler County, Cities and towns
Cities and towns in Butler County
The Census Bureau estimates 200,169 residents in Butler County for July 1, 2025, 6,143 more than in 2020 (+3.2%). That works out to 254 people per square mile of land. No town dominates: Butler, the largest, has 12,879 residents, 6.4% of the total. Together its 24 incorporated places hold 17.8% of those residents; the other 82.2% live outside any of them. CDC's 1,492 reported tests for 2020 work out to 7.5 per 1,000 residents (2025 estimate), close to Pennsylvania's 7.2.
From Butler to Cherry Valley, CDC publishes no figure by town: each reads Butler County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Butler | 12,879 | −4.5% | 6.4% |
| Zelienople | 3,752 | −4.1% | 1.9% |
| Slippery Rock | 3,551 | +11.6% | 1.8% |
| Seven Fields | 2,864 | −2.2% | 1.4% |
| Evans City | 1,670 | −4.4% | 0.8% |
| Mars | 1,391 | −3.9% | 0.7% |
| Saxonburg | 1,368 | −4.2% | 0.7% |
| Prospect | 1,086 | −3.8% | 0.5% |
| Harmony | 905 | −4.1% | 0.5% |
| Chicora | 870 | −4.2% | 0.4% |
| Connoquenessing | 809 | +19.1% | 0.4% |
| Harrisville | 782 | −4.0% | 0.4% |
- East Butler
- Valencia
- Bruin
- Callery
- West Liberty
- Eau Claire
- Portersville
- Fairview
- West Sunbury
- Petrolia
- Karns City
- Cherry Valley
24 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025).
Butler County, Homes
Homes in Butler County
Of Butler County's 86,399 homes, 70% are detached houses, against 57% across Pennsylvania; 10% are in buildings of five or more homes. Much of Butler County is recent building: 24% of its homes have gone up since 2000 and the middle year built is 1979, against 1965 for Pennsylvania. Owners live in 76% of the occupied homes (Pennsylvania: 69%), so for most households a test and a fix are their own to order.
| Homes | Butler County | Pennsylvania |
|---|---|---|
| Housing units | 86,399 | 5,779,663 |
| Detached houses | 70% | 57% |
| In buildings of 5 or more | 10% | 13% |
| Mobile homes | 7% | 4% |
| Built before 1960 | 30% | 45% |
| Built since 2000 | 24% | 14% |
| Middle year built | 1979 | 1965 |
| Owner-occupied | 76% | 69% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.