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Radon Levels in Ashland County, Ohio

EPA puts Ashland County in Zone 1, its highest radon zone, and high results are common there: 62.9% of the 340 radon tests reported to CDC (2008 to 2017, laboratory totals) 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

    62.9%

    10.6 pts above OH

    Ashland
    62.9%
    Ohio
    52.3%

    340 tests, 2008 to 2017

  • Median result

    5.4pCi/L

    Action level reached

    Ashland
    5.4 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    340

    45th of 79 by tests

    Ashland
    340
    Franklin
    16,142

    Reported to CDC before any fix, 2008 to 2017

  • 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 Ohio

    18 of 79

    Top quarter

    Ashland
    62.9%
    Pickaway
    81.4%

    By share, of 79 with 30+ tests

Read a result for Ashland County

Starts at Ashland County's median, 5.4 pCi/L

5.4pCi/L

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

EPA’s reading of 5.4 pCi/L

At or above 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 at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. Ashland County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Ashland County, At a glance

Ashland County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Ashland 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 68% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Ashland County, 2008 to 2017, laboratory

Reported results by concentration band, Ashland County, 2008 to 2017, laboratory
Under 2 pCi/L: 16%2 to 4 pCi/L: 21%4 pCi/L and above: 63%

Of 340 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Ashland County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L5616.5%
2 to 4 pCi/L7020.6%
4 pCi/L and above21462.9%
What these figures count

These are the 340 tests reported to CDC for Ashland 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).

How to read these figures

Ashland County, Compared

Ashland County radon figures, compared

Calculated by Radon411

More than half: 62.9% of the 340 radon tests reported to CDC for Ashland County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 18th of 79 Ohio counties with 30 or more tests for the same period. That is 10.6 points above the 52.3% pooled from 88 Ohio counties.

The median result, 5.4 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 264.7 pCi/L. The rest split 16.5% under 2 pCi/L and 20.6% from 2 to 4 (Ohio: 23.1% and 24.6%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 62.9% share point the same way here.

2 of its 7 bordering counties with figures ran higher, led by Knox County at 72.0%; Medina County reported 43.4%. Statewide for the same period, Pickaway County reported the highest share (81.4%) and Cuyahoga County the lowest (21.7%).

CDC's ten-year totals for Ashland County went from 261 tests (2005 to 2014) to 340 (2008 to 2017), the share going from 60.5% to 62.9%.

Nationally, every county with a figure for the same period pools to 35.7%; Ashland County sits 27.2 points above it. CDC also counts 51 tests taken after mitigation in Ashland County for the same period: tests in homes where a fix was already in.

Ashland County against Ohio, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Ashland County
Ashland County34062.9%5.4 pCi/LThis county
Ohio, pooled88 counties, pooled98,84052.3%Not pooled−10.6 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−27.2 points
Pickaway Countyhighest in the state18381.4%9.5 pCi/L+18.5 points
Cuyahoga Countylowest in the state10,09221.7%2.0 pCi/L−41.2 points
Knox County, OHborders it1,53072.0%8.1 pCi/L+9.1 points
Holmes County, OHborders it6764.2%5.8 pCi/L+1.3 points
Richland County, OHborders it1,32762.2%5.2 pCi/L−0.7 points
Wayne County, OHborders it1,07461.8%4.9 pCi/L−1.1 points
Huron County, OHborders it79659.4%4.9 pCi/L−3.5 points
Lorain County, OHborders it3,30745.4%3.6 pCi/L−17.5 points
Medina County, OHborders it2,13943.4%3.5 pCi/L−19.5 points
Where Ashland County's reported results fell, 2008 to 2017, laboratory, beside Ohio and the United States
ResultAshland County testsAshland County shareOhio shareU.S. shareAgainst Ohio
Under 2 pCi/L5616.5%23.1%39.6%−6.6 points
2 to 4 pCi/L7020.6%24.6%24.7%−4.0 points
4 pCi/L and above21462.9%52.3%35.7%+10.6 points
Ashland County ranked among the 79 Ohio counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Marion County13 of 7926565.3%6.4 pCi/L
Miami County14 of 7969065.2%6.1 pCi/L
Morrow County15 of 7917765.0%5.7 pCi/L
Holmes County16 of 796764.2%5.8 pCi/L
Darke County17 of 7927063.7%5.6 pCi/L
Ashland County18 of 7934062.9%5.4 pCi/L
Preble County19 of 7921262.7%5.5 pCi/L
Richland County20 of 791,32762.2%5.2 pCi/L
Wayne County21 of 791,07461.8%4.9 pCi/L
Henry County22 of 793461.8%5.3 pCi/L
Union County23 of 791,28560.2%4.8 pCi/L
Ashland County ten-year laboratory totals, against Ohio's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestOhio, pooledChange from the row before
2008 to 201734062.9%5.4 pCi/L264.7 pCi/L52.3%+0.8 points
2007 to 201633862.1%5.3 pCi/L264.7 pCi/L52.8%+1.7 points
2006 to 201529360.4%4.9 pCi/L264.7 pCi/L52.9%−0.1 points
2005 to 201426160.5%5.0 pCi/L264.7 pCi/L52.4%First on file

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

Ashland County, Geology

The ground under Ashland County

Predicted

USGS's geologic map splits Ashland County: 68.5% of its land is high radon potential and 31.5% moderate. The map puts 65.7% of Ashland County in the area it calls Area of Elevated Radioactivity and 31.5% in Glaciated Plateau, with one smaller area beside them. USGS gives the first a radon index of 12, in the high band (12 to 17), and the second 11, in the moderate band (9 to 11).

USGS's geologic areas under Ashland County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Area of Elevated RadioactivityPennsylvanian shale, sandstone, coal, and limestone.High1265.7%
Glaciated PlateauDevonian, Mississippian and Permian carbonates and shales.Moderate1131.5%
Glaciated PlateauPre-Wisconsin glacial deposits derived from high radioactivity marine black shale.High122.7%

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

Ashland County beside the ground around it

On high-potential ground Ashland County is close to Ohio as a whole: 68.5% of its land against 62.8%. Of the 7 counties that border it, 3 have more high-potential ground, Holmes County the most at 100%.

Share of land by USGS radon potential: Ashland County, the 7 counties bordering it and Ohio
AreaEPA zoneLow potentialModerate potentialHigh potential
Ashland CountyZone 1None31.5%68.5%
Richland CountyZone 1None6.3%93.7%
Wayne CountyZone 1None34.6%65.4%
Medina CountyZone 2None100%None
Holmes CountyZone 1NoneNone100%
Huron CountyZone 1None32.6%67.4%
Knox CountyZone 1NoneNone100%
Lorain CountyZone 2None100%None
Ohio88 counties, pooled by land areaVariesNone37.2%62.8%

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

Local help

Ashland County, Local resources

Radon testing and mitigation in Ashland County

Listed radon businesses with an address in Ashland County:

Listed radon professionals by town: Ashland

What Ohio's program says
Phone
614-728-0272
Email
indoor.radon@odh.ohio.gov
Licensing of radon professionals
This program licenses companies and persons directly involved with the radon testing and mitigation industry.

What it means

Ashland County, Questions

Questions about radon in Ashland County

Are radon levels high in Ashland County?

Over the 2008 to 2017 laboratory totals, 62.9% of the radon tests reported to CDC for Ashland County, Ohio were at or above 4 pCi/L, and the median reported pre-mitigation result was 5.4 pCi/L. Of 79 Ohio counties with 30 or more tests for the same period, 17 reported a higher share; pooled, the state comes to 52.3%.

Which counties border Ashland County?

Ashland County borders 7 counties: Richland County, Wayne County, Medina County, Holmes County, Huron County, Knox County and Lorain County.

Products

Ashland County, Products

Testing a home in Ashland County

In Ashland County, 62.9% of 340 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 52.3% pooled across Ohio. In Zone 1 the year-round level in Ashland 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

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

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Ashland County, Bordering counties

Counties bordering Ashland County

Calculated by Radon411

Ashland County, Cities and towns

Cities and towns in Ashland County

Ashland County's population has barely moved since 2020: 52,523 residents on July 1, 2025 against 52,485 then, by the Census Bureau's estimates. That works out to 124 people per square mile of land. Its largest town, Ashland, has 18,730 residents, 35.7% of the total. CDC's 340 reported tests for 2008 to 2017 work out to 6.5 per 1,000 residents (2025 estimate), close to Ohio's 8.3.

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

The cities and towns in Ashland County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Ashland18,730−2.5%35.7%
Loudonvilleextends beyond Ashland County2,733−1.6%Counted whole
Perrysville729−0.3%1.4%
Jeromesville529−0.9%1.0%
Hayesville441−0.5%0.8%
Bailey Lakes347−0.6%0.7%
Savannah331+0.6%0.6%
Polk306−1.0%0.6%
Mifflin154−1.3%0.3%

9 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). A place that extends beyond Ashland County is counted whole, so it has no share.

Ashland County, Homes

Homes in Ashland County

Ashland County is a place of houses on their own lots: 81% of its 22,517 homes are detached single-family houses, against 69% across Ohio. Half of its homes were built before 1968, close to Ohio's 1970: 43% date from before 1960 and 16% from 2000 or later. Owners live in 79% of the occupied homes (Ohio: 67%), so for most households a test and a fix are their own to order.

Homes in Ashland County, Ohio, 2019 to 2023
HomesAshland CountyOhio
Housing units22,5175,271,573
Detached houses81%69%
In buildings of 5 or more6%15%
Mobile homes4%4%
Built before 196043%38%
Built since 200016%16%
Middle year built19681970
Owner-occupied79%67%

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