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Radon Levels in Huron County, Ohio

EPA puts Huron County in Zone 1, its highest radon zone, and high results are common there: 59.4% of the 796 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

    59.4%

    7.1 pts above OH

    Huron
    59.4%
    Ohio
    52.3%

    796 tests, 2008 to 2017

  • Median result

    4.9pCi/L

    Action level reached

    Huron
    4.9 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    796

    28th of 79 by tests

    Huron
    796
    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

    28 of 79

    Middle half

    Huron
    59.4%
    Pickaway
    81.4%

    By share, of 79 with 30+ tests

Read a result for Huron County

Starts at Huron County's median, 4.9 pCi/L

4.9pCi/L

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

EPA’s reading of 4.9 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. Huron County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Huron County, At a glance

Huron County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Huron 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 67% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

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

Reported results by concentration band, Huron County, 2008 to 2017, laboratory
Under 2 pCi/L: 19%2 to 4 pCi/L: 22%4 pCi/L and above: 59%

Of 796 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Huron County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L15119.0%
2 to 4 pCi/L17221.6%
4 pCi/L and above47359.4%
What these figures count

These are the 796 tests reported to CDC for Huron 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

Huron County, Compared

Huron County radon figures, compared

Calculated by Radon411

More than half: 59.4% of the 796 radon tests reported to CDC for Huron County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 28th of 79 Ohio counties with 30 or more tests for the same period. That is 7.1 points above the 52.3% pooled from 88 Ohio counties.

The median result, 4.9 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 78.9 pCi/L. The rest split 19.0% under 2 pCi/L and 21.6% from 2 to 4 (Ohio: 23.1% and 24.6%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 59.4% share point the same way here.

3 of its 7 bordering counties with figures ran higher, led by Ashland County at 62.9%; Lorain County reported 45.4%. 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 Huron County went from 494 tests (2005 to 2014) to 796 (2008 to 2017), the share going from 59.7% to 59.4%.

Nationally, every county with a figure for the same period pools to 35.7%; Huron County sits 23.7 points above it. CDC also counts 163 tests taken after mitigation in Huron County for the same period: tests in homes where a fix was already in.

Huron County against Ohio, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Huron County
Huron County79659.4%4.9 pCi/LThis county
Ohio, pooled88 counties, pooled98,84052.3%Not pooled−7.1 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−23.7 points
Pickaway Countyhighest in the state18381.4%9.5 pCi/L+22.0 points
Cuyahoga Countylowest in the state10,09221.7%2.0 pCi/L−37.7 points
Ashland County, OHborders it34062.9%5.4 pCi/L+3.5 points
Richland County, OHborders it1,32762.2%5.2 pCi/L+2.8 points
Crawford County, OHborders it21059.5%4.7 pCi/L+0.1 points
Sandusky County, OHborders it64959.2%5.0 pCi/L−0.2 points
Seneca County, OHborders it54058.9%4.9 pCi/L−0.5 points
Erie County, OHborders it1,65154.5%4.4 pCi/L−4.9 points
Lorain County, OHborders it3,30745.4%3.6 pCi/L−14.0 points
Where Huron County's reported results fell, 2008 to 2017, laboratory, beside Ohio and the United States
ResultHuron County testsHuron County shareOhio shareU.S. shareAgainst Ohio
Under 2 pCi/L15119.0%23.1%39.6%−4.1 points
2 to 4 pCi/L17221.6%24.6%24.7%−3.0 points
4 pCi/L and above47359.4%52.3%35.7%+7.1 points
Huron 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
Union County23 of 791,28560.2%4.8 pCi/L
Stark County24 of 793,31760.1%4.9 pCi/L
Shelby County25 of 7924860.1%5.2 pCi/L
Putnam County26 of 799459.6%4.8 pCi/L
Crawford County27 of 7921059.5%4.7 pCi/L
Huron County28 of 7979659.4%4.9 pCi/L
Sandusky County29 of 7964959.2%5.0 pCi/L
Coshocton County30 of 7911258.9%5.1 pCi/L
Seneca County31 of 7954058.9%4.9 pCi/L
Greene County32 of 792,60258.6%4.9 pCi/L
Monroe County33 of 794858.3%5.0 pCi/L
Huron County ten-year laboratory totals, against Ohio's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestOhio, pooledChange from the row before
2008 to 201779659.4%4.9 pCi/L78.9 pCi/L52.3%+1.2 points
2007 to 201678458.2%4.8 pCi/L78.9 pCi/L52.8%−1.7 points
2006 to 201564159.9%4.8 pCi/L78.9 pCi/L52.9%+0.2 points
2005 to 201449459.7%4.8 pCi/L76.8 pCi/L52.4%First on file

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

Huron County, Geology

The ground under Huron County

Predicted

USGS's geologic map splits Huron County: 67.4% of its land is high radon potential and 32.6% moderate. The map puts 67.4% of Huron County in the area it calls Till Plains and 32.6% in Glaciated Plateau. USGS gives the first a radon index of 14, in the high band (12 to 17), and the second 11, in the moderate band (9 to 11).

USGS's geologic areas under Huron County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Till PlainsGlacial deposits underlain by Ordovician through Devonian limestone and shale.High1467.4%
Glaciated PlateauDevonian, Mississippian and Permian carbonates and shales.Moderate1132.6%

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

Huron County beside the ground around it

On high-potential ground Huron County is close to Ohio as a whole: 67.4% of its land against 62.8%. Of the 7 counties that border it, 4 have more high-potential ground, Crawford County the most at 100%.

Share of land by USGS radon potential: Huron County, the 7 counties bordering it and Ohio
AreaEPA zoneLow potentialModerate potentialHigh potential
Huron CountyZone 1None32.6%67.4%
Erie CountyZone 2None56.5%41.3%
Lorain CountyZone 2None100%None
Richland CountyZone 1None6.3%93.7%
Crawford CountyZone 1NoneNone100%
Seneca CountyZone 1None0.6%99.4%
Ashland CountyZone 1None31.5%68.5%
Sandusky CountyZone 2None53.0%46.5%
Ohio88 counties, pooled by land areaVariesNone37.2%62.8%

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

Local help

Huron County, Local resources

Radon testing and mitigation in Huron County

Listed radon businesses with an address in Huron County:

Listed radon professionals by town: Bellevue, Greenwich, Wakeman

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

Huron County, Questions

Questions about radon in Huron County

Are radon levels high in Huron County?

Over the 2008 to 2017 laboratory totals, 59.4% of the radon tests reported to CDC for Huron County, Ohio were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.9 pCi/L. Of 79 Ohio counties with 30 or more tests for the same period, 27 reported a higher share; pooled, the state comes to 52.3%.

Which counties border Huron County?

Huron County borders 7 counties: Erie County, Lorain County, Richland County, Crawford County, Seneca County, Ashland County and Sandusky County.

Products

Huron County, Products

Testing a home in Huron County

In Huron County, 59.4% of 796 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 Huron 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

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

Explore

Huron County, Bordering counties

Counties bordering Huron County

Calculated by Radon411

Huron County, Cities and towns

Cities and towns in Huron County

Huron County's population has barely moved since 2020: 58,250 residents on July 1, 2025 against 58,487 then, by the Census Bureau's estimates. That works out to 118 people per square mile of land. Its largest town, Norwalk, has 17,191 residents, 29.5% of the total. Testing is reported here more often than across the state: CDC's 796 reported tests for 2008 to 2017 come to 13.7 for every 1,000 residents (2025 estimate), against 8.3 for Ohio.

From Norwalk to North Fairfield, CDC publishes no figure by town: each reads Huron County's.

The cities and towns in Huron County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Norwalk17,191+0.9%29.5%
Bellevueextends beyond Huron County8,154−1.1%Counted whole
Willard6,130−1.3%10.5%
New London2,368−2.0%4.1%
Plymouthextends beyond Huron County1,702−0.9%Counted whole
Greenwich1,382−1.2%2.4%
Milanextends beyond Huron County1,344−1.8%Counted whole
Monroeville1,283−1.2%2.2%
Wakeman1,019+2.9%1.7%
North Fairfield443−1.8%0.8%

10 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 Huron County is counted whole, so it has no share.

Huron County, Homes

Homes in Huron County

Of Huron County's 25,575 homes, 72% are detached houses, against 69% across Ohio; 7% are mobile homes. Half of its homes were built before 1967, close to Ohio's 1970: 42% date from before 1960 and 12% from 2000 or later. 74% of occupied homes are lived in by their owner (Ohio: 67%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Huron County, Ohio, 2019 to 2023
HomesHuron CountyOhio
Housing units25,5755,271,573
Detached houses72%69%
In buildings of 5 or more6%15%
Mobile homes7%4%
Built before 196042%38%
Built since 200012%16%
Middle year built19671970
Owner-occupied74%67%

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