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Radon Levels in Crawford County, Ohio

EPA puts Crawford County in Zone 1, its highest radon zone, and high results are common there: 59.5% of the 210 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

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  • Share at 4+ pCi/L

    59.5%

    7.2 pts above OH

    Crawford
    59.5%
    Ohio
    52.3%

    210 tests, 2008 to 2017

  • Median result

    4.7pCi/L

    Action level reached

    Crawford
    4.7 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    210

    55th of 79 by tests

    Crawford
    210
    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

    27 of 79

    Middle half

    Crawford
    59.5%
    Pickaway
    81.4%

    By share, of 79 with 30+ tests

Read a result for Crawford County

Starts at Crawford County's median, 4.7 pCi/L

4.7pCi/L

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

EPA’s reading of 4.7 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. Crawford County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Crawford County, At a glance

Crawford County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Crawford 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 100% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

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

Reported results by concentration band, Crawford County, 2008 to 2017, laboratory
Under 2 pCi/L: 12%2 to 4 pCi/L: 29%4 pCi/L and above: 59%

Of 210 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Crawford County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L2511.9%
2 to 4 pCi/L6028.6%
4 pCi/L and above12559.5%
What these figures count

These are the 210 tests reported to CDC for Crawford 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

Crawford County, Compared

Crawford County radon figures, compared

Calculated by Radon411

More than half: 59.5% of the 210 radon tests reported to CDC for Crawford County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 27th of 79 Ohio counties with 30 or more tests for the same period. That is 7.2 points above the 52.3% pooled from 88 Ohio counties.

The median result, 4.7 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 51.7 pCi/L. The rest split 11.9% under 2 pCi/L and 28.6% from 2 to 4 (Ohio: 23.1% and 24.6%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 59.5% share point the same way here.

3 of its 6 bordering counties with figures ran higher, led by Marion County at 65.3%; Wyandot County reported 46.3%. 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 Crawford County went from 230 tests (2005 to 2014) to 210 (2008 to 2017), the share going from 59.1% to 59.5%.

Nationally, every county with a figure for the same period pools to 35.7%; Crawford County sits 23.8 points above it. CDC also counts 30 tests taken after mitigation in Crawford County for the same period: tests in homes where a fix was already in.

Crawford County against Ohio, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Crawford County
Crawford County21059.5%4.7 pCi/LThis county
Ohio, pooled88 counties, pooled98,84052.3%Not pooled−7.2 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−23.8 points
Pickaway Countyhighest in the state18381.4%9.5 pCi/L+21.9 points
Cuyahoga Countylowest in the state10,09221.7%2.0 pCi/L−37.8 points
Marion County, OHborders it26565.3%6.4 pCi/L+5.8 points
Morrow County, OHborders it17765.0%5.7 pCi/L+5.5 points
Richland County, OHborders it1,32762.2%5.2 pCi/L+2.7 points
Huron County, OHborders it79659.4%4.9 pCi/L−0.1 points
Seneca County, OHborders it54058.9%4.9 pCi/L−0.6 points
Wyandot County, OHborders it32046.3%3.6 pCi/L−13.2 points
Where Crawford County's reported results fell, 2008 to 2017, laboratory, beside Ohio and the United States
ResultCrawford County testsCrawford County shareOhio shareU.S. shareAgainst Ohio
Under 2 pCi/L2511.9%23.1%39.6%−11.2 points
2 to 4 pCi/L6028.6%24.6%24.7%+4.0 points
4 pCi/L and above12559.5%52.3%35.7%+7.2 points
Crawford 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
Henry County22 of 793461.8%5.3 pCi/L
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
Crawford County ten-year laboratory totals, against Ohio's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestOhio, pooledChange from the row before
2008 to 201721059.5%4.7 pCi/L51.7 pCi/L52.3%−1.5 points
2007 to 201623661.0%4.8 pCi/L51.7 pCi/L52.8%+0.8 points
2006 to 201523660.2%4.7 pCi/L51.7 pCi/L52.9%+1.1 points
2005 to 201423059.1%4.7 pCi/L51.7 pCi/L52.4%First on file

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

Crawford County, Geology

The ground under Crawford County

Predicted

USGS's geologic map puts all of Crawford County's mapped land in one class: high radon potential. All of it lies in the area the map calls Till Plains, to which USGS gives a radon index of 14, in the high band (12 to 17).

USGS's geologic areas under Crawford County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Till PlainsGlacial deposits underlain by Ordovician through Devonian limestone and shale.High14100%

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

Crawford County beside the ground around it

Crawford County has more high-potential ground than Ohio as a whole: 100% of its land against 62.8%. Of the 6 counties that border it, none has as large a share of high-potential ground; Marion County comes nearest at 100%.

Share of land by USGS radon potential: Crawford County, the 6 counties bordering it and Ohio
AreaEPA zoneLow potentialModerate potentialHigh potential
Crawford CountyZone 1NoneNone100%
Seneca CountyZone 1None0.6%99.4%
Richland CountyZone 1None6.3%93.7%
Wyandot CountyZone 1NoneNone100%
Morrow CountyZone 1NoneNone100%
Marion CountyZone 1NoneNone100%
Huron CountyZone 1None32.6%67.4%
Ohio88 counties, pooled by land areaVariesNone37.2%62.8%

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

Local help

Crawford County, Local resources

Radon testing and mitigation in Crawford County

Listed radon professionals by town: Galion

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

Crawford County, Questions

Questions about radon in Crawford County

Are radon levels high in Crawford County?

Over the 2008 to 2017 laboratory totals, 59.5% of the radon tests reported to CDC for Crawford County, Ohio were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.7 pCi/L. Of 79 Ohio counties with 30 or more tests for the same period, 26 reported a higher share; pooled, the state comes to 52.3%.

Which counties border Crawford County?

Crawford County borders 6 counties: Seneca County, Richland County, Wyandot County, Morrow County, Marion County and Huron County.

Products

Crawford County, Products

Testing a home in Crawford County

In Crawford County, 59.5% of 210 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 Crawford 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

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

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Crawford County, Bordering counties

Counties bordering Crawford County

Calculated by Radon411

Crawford County, Cities and towns

Cities and towns in Crawford County

Crawford County's population has barely moved since 2020: 41,896 residents on July 1, 2025 against 42,013 then, by the Census Bureau's estimates. That works out to 104 people per square mile of land. Its largest town, Bucyrus, has 11,631 residents, 27.8% of the total. Reported testing is thin here: 210 tests over 2008 to 2017, or 5.0 for every 1,000 residents (2025 estimate), where Ohio as a whole comes to 8.3.

From Bucyrus to Chatfield, CDC publishes no figure by town: each reads Crawford County's.

The cities and towns in Crawford County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Bucyrus11,631−0.4%27.8%
Galionextends beyond Crawford County10,370−0.7%Counted whole
Crestlineextends beyond Crawford County4,487−0.8%Counted whole
New Washington863−0.6%2.1%
North Robinson219Level0.5%
Tiro218−1.4%0.5%
Chatfield202−1.0%0.5%

7 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 Crawford County is counted whole, so it has no share.

Crawford County, Homes

Homes in Crawford County

Crawford County is a place of houses on their own lots: 80% of its 19,844 homes are detached single-family houses, against 69% across Ohio. The homes are older than Ohio's as a whole: half were built before 1958 (1970 for Ohio), and 53% date from before 1960. 71% 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 Crawford County, Ohio, 2019 to 2023
HomesCrawford CountyOhio
Housing units19,8445,271,573
Detached houses80%69%
In buildings of 5 or more6%15%
Mobile homes3%4%
Built before 196053%38%
Built since 20009%16%
Middle year built19581970
Owner-occupied71%67%

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