Short-term kit
Air Chek Short-Term radon test kit you hang, lab fee included
- Lab fee included
In home: 72 to 168 hours
Locations and reports
Radon Levels in Mercer County, Pennsylvania
EPA puts Mercer County in Zone 2, its middle radon zone, and 31.4% of its 318 reported radon tests (2020) were 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
31.4%
1.1 pts above PA
- Mercer
- 31.4%
- PA
- 30.3%
318 tests, 2020
Median result
2.5pCi/L
Below action level
- Mercer
- 2.5 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2020
Tests reported
318
35th of 63 by tests
- Mercer
- 318
- Montgomery
- 10,508
Reported to CDC before any fix, 2020
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Rank in PA
45 of 63
Middle half
- Mercer
- 31.4%
- Perry
- 57.7%
By share, of 63 with 30+ tests
Read a result for Mercer County
Starts at Mercer County's median, 2.5 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.5 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. Mercer County's median reported result, 2020.
The data
Mercer County, At a glance
Mercer County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Mercer County is a
USGS geologic potential: Moderate across 99% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Mercer County, 2020
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 34.4% |
| 2015 | 36.5% |
| 2016 | 31.0% |
| 2017 | 39.0% |
| 2018 | 27.2% |
| 2019 | 30.8% |
| 2020 | 31.4% |
2020: 31.4%. Across these years the share ran from 27.2% to 39.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 318 tests reported to CDC for Mercer 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).
Mercer County, Compared
Mercer County radon figures, compared
Calculated by Radon411In Mercer County, about 3 in 10 reported tests in 2020 (100 of 318) were at or above EPA's action level. Against the national pool of 25.5%, the gap is 5.9 points higher. Across 67 Pennsylvania counties pooled together, 30.3% of tests reached that level, so Mercer County runs 1.1 points above its state.
Of 4 neighbours with a figure, 3 reported a larger share at or above 4 pCi/L and 1 a smaller one; the spread is 29.9% (Crawford County) to 42.3% (Butler County). By share, Mercer County is 45th of 63 Pennsylvania counties with 30 or more tests for the same period.
Year by year, 2014 opened at 34.4% and 2020 closed at 31.4% (down 3.0 points), with 2017 the high at 39.0%. Half the tests came in under 2.5 pCi/L and half over it; the single highest reached 369.3 pCi/L. Below the action level, 127 tests (39.9%) came in under 2 pCi/L, against 44.3% statewide, and 91 tests (28.6%) fell between 2 and 4, against 25.4% statewide.
Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 31.4% share point the same way here. USGS geology rates 99% of the county's land moderate radon potential.
The busiest year on file was 2014, with 331 tests reported; the quietest, 2015, had 274.
Mercer CountyPennsylvania, pooled
| Year | Tests | Mercer County, at or above 4 pCi/L | Pennsylvania, pooled |
|---|---|---|---|
| 2014 | 331 | 34.4% | 36.1% |
| 2015 | 274 | 36.5% | 37.8% |
| 2016 | 303 | 31.0% | 34.4% |
| 2017 | 310 | 39.0% | 35.1% |
| 2018 | 305 | 27.2% | 30.5% |
| 2019 | 299 | 30.8% | 31.4% |
| 2020 | 318 | 31.4% | 30.3% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Mercer County, State data
Pennsylvania's own radon test data
MeasuredWhat Pennsylvania's own agencies publish about radon tests in Mercer 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 Mercer County
Pennsylvania DEP publishes its figures by ZIP code, not by county. These are the 27 ZIP codes that lie wholly or partly in Mercer County, each with the state's own figures for it. Period: Period not stated by DEP.
| ZIP code | What the state reports |
|---|---|
| 16057 | Basement: average 5.9 pCi/L, 782 tests; First floor: average 2.6 pCi/L, 65 tests |
| 16110 | Basement: figures not shown; First floor: figures not shown |
| 16113 | Basement: figures not shown |
| 16114 | Basement: average 6.7 pCi/L, 34 tests; First floor: figures not shown |
| 16121 | Basement: average 3.0 pCi/L, 159 tests; First floor: figures not shown |
| 16124 | Basement: average 4.9 pCi/L, 50 tests; First floor: figures not shown |
| 16125 | Basement: average 5.3 pCi/L, 825 tests; First floor: average 2.3 pCi/L, 167 tests |
| 16127 | Basement: average 4.5 pCi/L, 1,205 tests; First floor: average 3.1 pCi/L, 125 tests |
| 16130 | Basement: average 5.7 pCi/L, 37 tests; First floor: figures not shown |
| 16133 | Basement: average 3.1 pCi/L, 48 tests; First floor: figures not shown |
| 16134 | Basement: average 5.2 pCi/L, 114 tests; First floor: figures not shown |
| 16137 | Basement: average 5.1 pCi/L, 888 tests; First floor: average 3.2 pCi/L, 133 tests |
| 16142 | Basement: average 5.3 pCi/L, 625 tests; First floor: average 3.4 pCi/L, 53 tests |
| 16143 | Basement: average 4.7 pCi/L, 158 tests; First floor: figures not shown |
| 16145 | Basement: average 7.2 pCi/L, 115 tests; First floor: figures not shown |
| 16146 | Basement: average 2.7 pCi/L, 508 tests; First floor: average 2.3 pCi/L, 36 tests |
| 16148 | Basement: average 3.8 pCi/L, 1,759 tests; First floor: average 2.1 pCi/L, 109 tests |
| 16150 | Basement: average 3.8 pCi/L, 435 tests; First floor: average 2.0 pCi/L, 43 tests |
| 16153 | Basement: average 4.2 pCi/L, 88 tests; First floor: figures not shown |
| 16154 | Basement: average 5.2 pCi/L, 109 tests; First floor: figures not shown |
| 16156 | Basement: average 4.3 pCi/L, 129 tests; First floor: figures not shown |
| 16159 | Basement: average 4.8 pCi/L, 246 tests; First floor: figures not shown |
| 16161 | Basement: figures not shown; First floor: figures not shown |
| 16311 | Basement: figures not shown; First floor: figures not shown |
| 16314 | Basement: average 8.4 pCi/L, 204 tests; First floor: figures not shown |
| 16342 | Basement: average 13.3 pCi/L, 43 tests; First floor: figures not shown |
| 16362 | Basement: figures not shown; First floor: figures not shown |
- 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.
Mercer County, Geology
The ground under Mercer County
PredictedMost of the ground under Mercer County is one class on USGS's geologic map: 99.1% of its land is moderate radon potential, with 0.9% high. 98.9% of it lies in the area the map calls Glaciated Pittsburgh Plateau, to which USGS gives a radon index of 11, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Glaciated Pittsburgh Plateau | Late-Wisconsin till overlying sandstone, shale, limestone, and coal. | Moderate | 11 | 98.9% |
| Pennsylvanian Rocks of the Pittsburgh Low Plateau | Pennsylvanian marine shale, siltstone, sandstone, limestone, and coal. | High | 14 | 0.9% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Mercer County beside the ground around it
Pennsylvania as a whole has more high-potential ground than Mercer County: 70.4% of its land, against 0.9% here. Of the 6 counties that border it, 4 have more high-potential ground, Butler County the most at 98.0%.
The map rates the ground, not the air in any home.
Local help
Mercer County, Local resources
Radon testing and mitigation in Mercer 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.
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
Mercer County, Questions
Questions about radon in Mercer County
Are radon levels high in Mercer County?
In 2020, 31.4% of the radon tests reported to CDC for Mercer County, Pennsylvania were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.5 pCi/L. Of 63 Pennsylvania counties with 30 or more tests for the same period, 44 reported a higher share; pooled, the state comes to 30.3%.
Which counties border Mercer County?
Mercer County borders 6 counties: Trumbull County, OH, Venango County, PA, Lawrence County, PA, Crawford County, PA, Mahoning County, OH and Butler County, PA.
Products
Mercer County, Products
Testing a home in Mercer County
In Mercer County, 31.4% of 318 tests reported to CDC in 2020 reached 4 pCi/L, against 30.3% pooled across Pennsylvania. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Mercer County; a long-term test tells the year-round average.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
Monitor
RadonScan USB-powered radon monitor with a color screen
- C-NRPP 2024/25: Not included
- Plug-in
- Alarm
- Screen
First reading: Within 5 minutes
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Mercer County, Bordering counties
Counties bordering Mercer County
Calculated by Radon411- Radon levels in Butler County, PAEPA zone 1
42.3%at or above 4 pCi/L
Median 3.3 pCi/L · 1,492 tests · 10.9 points above Mercer County
- Radon levels in Lawrence County, PAEPA zone 2
36.0%at or above 4 pCi/L
Median 2.7 pCi/L · 286 tests · 4.6 points above Mercer County
- Radon levels in Venango County, PAEPA zone 1
34.1%at or above 4 pCi/L
Median 3.0 pCi/L · 179 tests · 2.7 points above Mercer County
- Radon levels in Crawford County, PAEPA zone 2
29.9%at or above 4 pCi/L
Median 2.6 pCi/L · 221 tests · 1.5 points below Mercer County
- Radon levels in Trumbull County, OHEPA zone 2
No CDC figure for 2020; its page reads it against its own neighbours.
- Radon levels in Mahoning County, OHEPA zone 2
No CDC figure for 2020; its page reads it against its own neighbours.
Mercer County, Cities and towns
Cities and towns in Mercer County
About 107,860 people live in Mercer County by the Census Bureau's estimate for July 1, 2025, 2,693 fewer than in 2020 (−2.4%). That works out to 160 people per square mile of land. No town dominates: Hermitage, the largest, has 16,308 residents, 15.1% of the total. Reported testing is thin here: 318 tests over 2020, or 2.9 for every 1,000 residents (2025 estimate), where Pennsylvania as a whole comes to 7.2.
From Hermitage to Wheatland, CDC publishes no figure by town: each reads Mercer County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Hermitage | 16,308 | −3.0% | 15.1% |
| Sharon | 12,648 | −3.6% | 11.7% |
| Grove City | 7,694 | −2.0% | 7.1% |
| Greenville | 5,406 | −2.0% | 5.0% |
| Farrell | 4,110 | −3.3% | 3.8% |
| Sharpsville | 4,095 | −3.6% | 3.8% |
| Mercer | 1,905 | −3.6% | 1.8% |
| Stoneboro | 922 | −2.5% | 0.9% |
| West Middlesex | 772 | −3.5% | 0.7% |
| Sandy Lake | 624 | −3.6% | 0.6% |
| Clark | 558 | −3.3% | 0.5% |
| Jamestown | 556 | −3.3% | 0.5% |
- Fredonia
- New Lebanon
- Jackson Center
- Sheakleyville
- Wheatland
17 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).
Mercer County, Homes
Homes in Mercer County
Of Mercer County's 50,884 homes, 75% are detached houses, against 57% across Pennsylvania; 9% are in buildings of five or more homes. Half of its homes were built before 1963, close to Pennsylvania's 1965: 47% date from before 1960 and 9% from 2000 or later. 73% 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 | Mercer County | Pennsylvania |
|---|---|---|
| Housing units | 50,884 | 5,779,663 |
| Detached houses | 75% | 57% |
| In buildings of 5 or more | 9% | 13% |
| Mobile homes | 7% | 4% |
| Built before 1960 | 47% | 45% |
| Built since 2000 | 9% | 14% |
| Middle year built | 1963 | 1965 |
| Owner-occupied | 73% | 69% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.