Short-term kitFirst Alert
RD1 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 2 to 4 days
Locations and reports
Radon Levels in Marion County, West Virginia
EPA puts Marion County in Zone 2, its middle radon zone, and 29.1% of its 244 reported radon tests (2008 to 2017, laboratory totals) 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
29.1%
8.4 pts below WV
- Marion
- 29.1%
- WV
- 37.5%
244 tests, 2008 to 2017
Median result
2.6pCi/L
Below action level
- Marion
- 2.6 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
244
9th of 27 by tests
- Marion
- 244
- Berkeley
- 2,888
Reported to CDC before any fix, 2008 to 2017
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 WV
17 of 27
Middle half
- Marion
- 29.1%
- Morgan
- 58.1%
By share, of 27 with 30+ tests
Read a result for Marion County
Starts at Marion County's median, 2.6 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.6 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. Marion County's median reported result, 2008 to 2017.
The data
Marion County, At a glance
Marion County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Marion County is a
USGS geologic potential: Moderate across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Marion County, 2008 to 2017, laboratory
Under 2 pCi/L: 39%2 to 4 pCi/L: 32%4 pCi/L and above: 29%
Of 244 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 95 | 38.9% |
| 2 to 4 pCi/L | 78 | 32.0% |
| 4 pCi/L and above | 71 | 29.1% |
What these figures count
These are the 244 tests reported to CDC for Marion County over 2008 to 2017 (laboratory totals), 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: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).
Marion County, Compared
Marion County radon figures, compared
Calculated by Radon411Marion County's 244 reported tests over the 2008 to 2017 laboratory totals had a middle value of 2.6 pCi/L and a maximum of 55.0 pCi/L, and 29.1% reached 4 pCi/L. West Virginia as a whole (55 West Virginia counties, pooled) comes to 37.5%: 8.4 points higher than here.
Among its state's counties it ranks 17th of 27 West Virginia counties with 30 or more tests for the same period. Statewide for the same period, Morgan County reported the highest share (58.1%) and Grant County the lowest (9.8%).
Below the action level, 95 tests (38.9%) came in under 2 pCi/L, against 37.7% statewide, and 78 tests (32.0%) fell between 2 and 4, against 24.7% statewide. CDC's ten-year totals for Marion County went from 195 tests (2005 to 2014) to 244 (2008 to 2017), the share going from 27.2% to 29.1%.
EPA's 1993 zone map puts Marion County in Zone 2, a predicted county average between 2 and 4 pCi/L. USGS geology rates 100% of the county's land moderate radon potential.
Next door, the shares run from 19.0% in Monongalia County to 36.4% in Harrison County, with Taylor County and Monongalia County below Marion County.
CDC also counts 35 tests taken after mitigation in Marion County for the same period: tests in homes where a fix was already in.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Marion County, Geology
The ground under Marion County
PredictedUSGS's geologic map puts all of Marion County's mapped land in one class: moderate radon potential. 97.9% of it lies in the area the map calls Central Allegheny Plateau, to which USGS gives a radon index of 10, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Central Allegheny Plateau | Permian and Pennsylvanian shale, siltstone, sandstone, minor limestone. | Moderate | 10 | 97.9% |
| Eastern Allegheny Plateau and Mtns | Devonian-Pennsylvanian shale, siltstone, sandstone, minor limestone and coal | Moderate | 10 | 2.1% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Marion County beside the ground around it
Across West Virginia 18.7% of the land is rated high; none of Marion County's is. Of the 4 counties that border it, none has as large a share of moderate-potential ground; Harrison County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Marion County, Local resources
Radon testing and mitigation in Marion County
Listed radon businesses with an address in Marion County:
- OEHS Radon ProgramOEHS Radon Program, run by WV DHHR OEHS Radiation, Toxics & Indoor Air Division, licenses or certifies radon professionals and offers free or discounted test kits, and answers questions about testing and mitigation in West Virginia.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
West Virginia residents can request a free Radon Test Kit by emailing Radon@wv.gov or calling 304-352-5039
- Compare kits
- Professionals in West Virginia35 professionals are listed in West Virginia.
Listed radon professionals by town: Fairmont
What West Virginia's program says
- Phone
- 304-352-5039
- Radon@wv.gov
- Licensing of radon professionals
Complete listings of professionals licensed to perform Asbestos, Lead, Radon and Clandestine Drug Laboratory Remediation activities in West Virginia.
What it means
Marion County, Questions
Questions about radon in Marion County
Are radon levels high in Marion County?
Over the 2008 to 2017 laboratory totals, 29.1% of the radon tests reported to CDC for Marion County, West Virginia were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.6 pCi/L. Of 27 West Virginia counties with 30 or more tests for the same period, 16 reported a higher share; pooled, the state comes to 37.5%.
Which counties border Marion County?
Marion County borders 4 counties: Harrison County, Monongalia County, Taylor County and Wetzel County.
Products
Marion County, Products
Testing a home in Marion County
In Marion County, 29.1% of 244 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 37.5% pooled across West Virginia. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Marion 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
MonitorPYZYCKYH
RD17 plug-in radon detector with a rechargeable battery and color screen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 6 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Marion County, Bordering counties
Counties bordering Marion County
Calculated by Radon411- Radon levels in Harrison CountyEPA zone 2
36.4%at or above 4 pCi/L
Median 2.6 pCi/L · 187 tests · 7.3 points above Marion County
- Radon levels in Wetzel CountyEPA zone 1
35.2%at or above 4 pCi/L
Median 2.7 pCi/L · 54 tests · 6.1 points above Marion County
- Radon levels in Taylor CountyEPA zone 2
28.1%at or above 4 pCi/L
Median 2.2 pCi/L · 32 tests · 1.0 points below Marion County
- Radon levels in Monongalia CountyEPA zone 1
19.0%at or above 4 pCi/L
Median 1.9 pCi/L · 1,176 tests · 10.1 points below Marion County
Marion County, Cities and towns
Cities and towns in Marion County
About 55,584 people live in Marion County by the Census Bureau's estimate for July 1, 2025, 656 fewer than in 2020 (−1.2%). That works out to 180 people per square mile of land. Its largest town, Fairmont, has 18,035 residents, 32.4% of the total. Together its 11 incorporated places hold 51.7% of those residents; the other 48.3% live outside any of them. CDC's 244 reported tests for 2008 to 2017 work out to 4.4 per 1,000 residents (2025 estimate), close to West Virginia's 5.7.
From Fairmont to Worthington, CDC publishes no figure by town: each reads Marion County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Fairmont | 18,035 | −2.1% | 32.4% |
| Pleasant Valley | 3,457 | −1.1% | 6.2% |
| Mannington | 1,910 | −2.4% | 3.4% |
| Barrackville | 1,196 | −1.2% | 2.2% |
| Monongah | 1,055 | +8.9% | 1.9% |
| Rivesville | 806 | −2.3% | 1.5% |
| White Hall | 700 | −0.7% | 1.3% |
| Grant Town | 669 | −2.3% | 1.2% |
| Farmington | 395 | +1.5% | 0.7% |
| Fairview | 367 | −1.3% | 0.7% |
| Worthington | 171 | −2.3% | 0.3% |
11 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).
Marion County, Homes
Homes in Marion County
Marion County is a place of houses on their own lots: 77% of its 26,283 homes are detached single-family houses, against 71% across West Virginia. The homes are older than West Virginia's as a whole: half were built before 1960 (1976 for West Virginia), and 50% date from before 1960. Owners live in 76% of the occupied homes (West Virginia: 74%), so for most households a test and a fix are their own to order.
| Homes | Marion County | West Virginia |
|---|---|---|
| Housing units | 26,283 | 859,653 |
| Detached houses | 77% | 71% |
| In buildings of 5 or more | 7% | 8% |
| Mobile homes | 8% | 14% |
| Built before 1960 | 50% | 33% |
| Built since 2000 | 14% | 18% |
| Middle year built | 1960 | 1976 |
| Owner-occupied | 76% | 74% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.