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Radon Levels in Portage County, Ohio

EPA puts Portage County in Zone 2, its middle radon zone, and 39.3% of its 1,661 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

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  • Share at 4+ pCi/L

    39.3%

    13.0 pts below OH

    Portage
    39.3%
    Ohio
    52.3%

    1,661 tests, 2008 to 2017

  • Median result

    3.2pCi/L

    Below action level

    Portage
    3.2 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    1,661

    15th of 79 by tests

    Portage
    1,661
    Franklin
    16,142

    Reported to CDC before any fix, 2008 to 2017

  • EPA radon zone

    Zone 2

    Moderate potential

    1. 1
    2. Zone 2
    3. 3

    1 highest, 3 lowest

    EPA predicts 2 to 4 pCi/L indoors

  • Rank in Ohio

    66 of 79

    Lowest quarter

    Portage
    39.3%
    Pickaway
    81.4%

    By share, of 79 with 30+ tests

Read a result for Portage County

Starts at Portage County's median, 3.2 pCi/L

3.2pCi/L

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

EPA’s reading of 3.2 pCi/L

Between 2 and 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 between 2 and 4 pCi/L. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. Portage County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Portage County, At a glance

Portage County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Portage County is a county: EPA's forecast for it as a whole is an average indoor of 2 to 4 pCi/L (75 to 150 Bq/m³). It describes no single address, and homes above EPA's are found in every zone, this one included.

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 Portage County, 2008 to 2017, laboratory

Reported results by concentration band, Portage County, 2008 to 2017, laboratory
Under 2 pCi/L: 29%2 to 4 pCi/L: 32%4 pCi/L and above: 39%

Of 1,661 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Portage County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L48028.9%
2 to 4 pCi/L52831.8%
4 pCi/L and above65339.3%
What these figures count

These are the 1,661 tests reported to CDC for Portage 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

Portage County, Compared

Portage County radon figures, compared

Calculated by Radon411

In Portage County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (653 of 1,661) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 3.6 points higher. Across 88 Ohio counties pooled together, 52.3% of tests reached that level, so Portage County runs 13.0 points below its state.

Of 6 neighbours with a figure, 1 reported a larger share at or above 4 pCi/L and 5 a smaller one; the spread is 21.7% (Cuyahoga County) to 60.1% (Stark County). By share, Portage County is 66th of 79 Ohio counties with 30 or more tests for the same period.

Half the tests came in under 3.2 pCi/L and half over it; the single highest reached 70.1 pCi/L. Below the action level, 480 tests (28.9%) came in under 2 pCi/L, against 23.1% statewide, and 528 tests (31.8%) fell between 2 and 4, against 24.6% statewide.

Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 39.3% share point the same way here. USGS geology rates 100% of the county's land moderate radon potential. CDC also counts 120 tests taken after mitigation in Portage County for the same period: tests in homes where a fix was already in.

CDC's ten-year totals for Portage County went from 1,104 tests (2005 to 2014) to 1,661 (2008 to 2017), the share going from 39.6% to 39.3%.

Portage County against Ohio, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Portage County
Portage County1,66139.3%3.2 pCi/LThis county
Ohio, pooled88 counties, pooled98,84052.3%Not pooled+13.0 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−3.6 points
Pickaway Countyhighest in the state18381.4%9.5 pCi/L+42.1 points
Lake Countylowest in the state2,34927.2%2.4 pCi/L−12.1 points
Stark County, OHborders it3,31760.1%4.9 pCi/L+20.8 points
Summit County, OHborders it6,48638.7%3.1 pCi/L−0.6 points
Trumbull County, OHborders it42534.6%2.9 pCi/L−4.7 points
Geauga County, OHborders it1,46923.4%2.4 pCi/L−15.9 points
Mahoning County, OHborders it66623.4%2.5 pCi/L−15.9 points
Cuyahoga County, OHborders it10,09221.7%2.0 pCi/L−17.6 points
Where Portage County's reported results fell, 2008 to 2017, laboratory, beside Ohio and the United States
ResultPortage County testsPortage County shareOhio shareU.S. shareAgainst Ohio
Under 2 pCi/L48028.9%23.1%39.6%+5.8 points
2 to 4 pCi/L52831.8%24.6%24.7%+7.2 points
4 pCi/L and above65339.3%52.3%35.7%−13.0 points
Portage 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
Medina County61 of 792,13943.4%3.5 pCi/L
Hardin County62 of 796743.3%3.4 pCi/L
Jackson County63 of 794841.7%3.3 pCi/L
Ottawa County64 of 7954140.3%2.9 pCi/L
Lucas County65 of 791,38140.2%3.0 pCi/L
Portage County66 of 791,66139.3%3.2 pCi/L
Summit County67 of 796,48638.7%3.1 pCi/L
Washington County68 of 7934938.1%3.1 pCi/L
Athens County69 of 7931838.1%3.1 pCi/L
Scioto County70 of 797337.0%2.7 pCi/L
Hamilton County71 of 793,75434.7%2.8 pCi/L
Portage County ten-year laboratory totals, against Ohio's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestOhio, pooledChange from the row before
2008 to 20171,66139.3%3.2 pCi/L70.1 pCi/L52.3%+0.1 points
2007 to 20161,48339.2%3.2 pCi/L70.1 pCi/L52.8%−1.4 points
2006 to 20151,28840.6%3.2 pCi/L70.1 pCi/L52.9%+1.0 points
2005 to 20141,10439.6%3.1 pCi/L70.1 pCi/L52.4%First on file

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

Portage County, Geology

The ground under Portage County

Predicted

USGS's geologic map puts all of Portage County's mapped land in one class: moderate radon potential. All of it lies in the area the map calls Glaciated Plateau, to which USGS gives a radon index of 11, in the moderate band (9 to 11).

USGS's geologic areas under Portage County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Glaciated PlateauDevonian, Mississippian and Permian carbonates and shales.Moderate11100%

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

Portage County beside the ground around it

Across Ohio 62.8% of the land is rated high; none of Portage County's is. Of the 6 counties that border it, 1 has more high-potential ground, Stark County the most at 43.8%.

Share of land by USGS radon potential: Portage County, the 6 counties bordering it and Ohio
AreaEPA zoneLow potentialModerate potentialHigh potential
Portage CountyZone 2None100%None
Summit CountyZone 1None100%None
Geauga CountyZone 2None100%None
Trumbull CountyZone 2None100%None
Mahoning CountyZone 2None100%None
Cuyahoga CountyZone 2None99.9%None
Stark CountyZone 1None56.2%43.8%
Ohio88 counties, pooled by land areaVariesNone37.2%62.8%

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

Local help

Portage County, Local resources

Radon testing and mitigation in Portage County

Listed radon businesses with an address in Portage County:

Listed radon professionals by town: Kent, Tallmadge, Aurora, Streetsboro, Ravenna, Mantua, Hiram

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

Portage County, Questions

Questions about radon in Portage County

Are radon levels high in Portage County?

Over the 2008 to 2017 laboratory totals, 39.3% of the radon tests reported to CDC for Portage County, Ohio were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.2 pCi/L. Of 79 Ohio counties with 30 or more tests for the same period, 65 reported a higher share; pooled, the state comes to 52.3%.

Which counties border Portage County?

Portage County borders 6 counties: Summit County, Geauga County, Trumbull County, Mahoning County, Cuyahoga County and Stark County.

Products

Portage County, Products

Testing a home in Portage County

In Portage County, 39.3% of 1,661 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 52.3% pooled across Ohio. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Portage County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Portage County homes, compared

Explore

Portage County, Bordering counties

Counties bordering Portage County

Calculated by Radon411

Portage County, Cities and towns

Cities and towns in Portage County

The Census Bureau estimates 163,404 residents in Portage County for July 1, 2025, 1,551 more than in 2020 (+1.0%). That works out to 335 people per square mile of land. No town dominates: Kent, the largest, has 27,737 residents, 17.0% of the total. CDC's 1,661 reported tests for 2008 to 2017 work out to 10.2 per 1,000 residents (2025 estimate), close to Ohio's 8.3.

From Kent to Sugar Bush Knolls, CDC publishes no figure by town: each reads Portage County's.

The cities and towns in Portage County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Kent27,737−1.5%17.0%
Tallmadgeextends beyond Portage County18,521+0.7%Counted whole
Aurora18,014+4.3%11.0%
Streetsboro17,730+2.4%10.9%
Ravenna11,136−1.4%6.8%
Mogadoreextends beyond Portage County3,816+0.3%Counted whole
Garrettsville2,450+0.3%1.5%
Windham1,675+0.7%1.0%
Mantua1,005+0.3%0.6%
Hiram1,000+0.6%0.6%
Sugar Bush Knolls219+1.4%0.1%

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

Portage County, Homes

Homes in Portage County

Of Portage County's 71,040 homes, 65% are detached houses, against 69% across Ohio; 16% are in buildings of five or more homes. Half of its homes were built before 1976, close to Ohio's 1970: 28% date from before 1960 and 21% from 2000 or later. 70% 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 Portage County, Ohio, 2019 to 2023
HomesPortage CountyOhio
Housing units71,0405,271,573
Detached houses65%69%
In buildings of 5 or more16%15%
Mobile homes6%4%
Built before 196028%38%
Built since 200021%16%
Middle year built19761970
Owner-occupied70%67%

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