Locations and reports
Radon Levels in Ohio
What this means for you
- Your area: EPA rates 53 of Ohio's 88 classified counties Zone 1, the highest of its three radon zones. Zones are predictions for whole counties, and homes with elevated levels occur in all three zones.
- Local tests: CDC publishes Ohio's radon test results by county. Open your county below to see its figures.
- Your home: The only way to know your home’s level is to test it.
pCi/L (picocuries per liter) is the unit radon is measured in. EPA recommends fixing a home at 4 pCi/L or above, its action level.
For Ohio, EPA's Map of Radon Zones places 53 of its 88 classified counties in Zone 1, highest predicted potential, a prediction for each county as a whole. Radon levels vary from home to home, so only a test measures the level in yours.
Predicted: EPA radon zone
88 of 88 counties classified
EPA classifies counties, not states. Of the 88 counties in Ohio with a zone, 53 are in Zone 1 and 35 in Zone 2.
- Zone 1: Highest predicted potentialgreater than 4 pCi/L53 of 88 counties · 60.2%
- Zone 2: Moderate predicted potential2 to 4 pCi/L35 of 88 counties · 39.8%
An EPA radon zone describes predicted potential across a whole county. It is not intended to determine whether any individual home should be tested, and homes with elevated levels occur in all three zones. EPA recommends testing every home regardless of zone, and testing is the only way to know the radon level in a specific building.
This is a county-level geologic prediction. It is not a measurement of any address, and houses with elevated radon are found in all three zones.
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
CDC publishes Ohio's radon test figures by county: 88 of its 88 counties have one. Each county's share is in the county list.
Ohio, In figures
Ohio in figures
What the published data says about Ohio, in words. A zone and a share of tests describe an area, never the level in any one home.
Predicted
PredictedEPA places 53 of Ohio's 88 counties in Zone 1 and 35 in Zone 2.
Zone 1 counties, A to Z, begin with Adams County, Allen County and Ashland County; the county section below lists all 53.
Compared
Calculated by Radon41160% of Ohio's counties with a zone on file are in Zone 1, a larger share than across all U.S. counties (34%). It is a share of counties, not of land, people or homes.
Reported tests
MeasuredCDC has no statewide testing figure for Ohio on file here.
88 of the 88 counties have a published county figure; the most tests in each one's latest year were reported for Franklin County (13,807 in 2017), Cuyahoga County (8,861 in 2017) and Summit County (6,002 in 2017).
Local record
Ohio's radon program is the Radon Education and Licensing Program, run by Ohio Department of Health; its contacts are under Local resources.
10 cities have a page setting the figures of the counties it lies in side by side: Columbus, Dayton, Cincinnati, Toledo, Cleveland, Akron, Westerville, Parma, Canton and Lancaster.
Ohio, Counties
Ohio counties by EPA zone
PredictedAll 88 counties, by the zone EPA predicts for each. Every county has its own report.
Zone 1: highest predicted potential53
- Adams County50.0% of reported tests at or above 4 pCi/L, 2017
- Allen County56.7% of reported tests at or above 4 pCi/L, 2017
- Ashland County62.9% of reported tests at or above 4 pCi/L, 2017
- Auglaize County71.2% of reported tests at or above 4 pCi/L, 2017
- Belmont County45.2% of reported tests at or above 4 pCi/L, 2017
- Butler County54.3% of reported tests at or above 4 pCi/L, 2017
- Carroll County57.4% of reported tests at or above 4 pCi/L, 2017
- Champaign County71.1% of reported tests at or above 4 pCi/L, 2017
- Clark County57.5% of reported tests at or above 4 pCi/L, 2017
- Clinton County52.4% of reported tests at or above 4 pCi/L, 2017
- Columbiana County49.1% of reported tests at or above 4 pCi/L, 2017
- Coshocton County58.9% of reported tests at or above 4 pCi/L, 2017
- Crawford County59.5% of reported tests at or above 4 pCi/L, 2017
- Darke County63.7% of reported tests at or above 4 pCi/L, 2017
- Delaware County72.2% of reported tests at or above 4 pCi/L, 2017
- Fairfield County76.8% of reported tests at or above 4 pCi/L, 2017
- Fayette County58.3% of reported tests at or above 4 pCi/L, 2017
- Franklin County71.9% of reported tests at or above 4 pCi/L, 2017
- Greene County58.6% of reported tests at or above 4 pCi/L, 2017
- Guernsey County44.4% of reported tests at or above 4 pCi/L, 2017
- Hamilton County34.7% of reported tests at or above 4 pCi/L, 2017
- Hancock County46.2% of reported tests at or above 4 pCi/L, 2017
- Hardin County43.3% of reported tests at or above 4 pCi/L, 2017
- Harrison County50.0% of reported tests at or above 4 pCi/L, 2017
- Holmes County64.2% of reported tests at or above 4 pCi/L, 2017
- Huron County59.4% of reported tests at or above 4 pCi/L, 2017
- Jefferson County49.8% of reported tests at or above 4 pCi/L, 2017
- Knox County72.0% of reported tests at or above 4 pCi/L, 2017
- Licking County71.2% of reported tests at or above 4 pCi/L, 2017
- Logan County73.6% of reported tests at or above 4 pCi/L, 2017
- Madison County67.4% of reported tests at or above 4 pCi/L, 2017
- Marion County65.3% of reported tests at or above 4 pCi/L, 2017
- Mercer County57.7% of reported tests at or above 4 pCi/L, 2017
- Miami County65.2% of reported tests at or above 4 pCi/L, 2017
- Montgomery County50.3% of reported tests at or above 4 pCi/L, 2017
- Morrow County65.0% of reported tests at or above 4 pCi/L, 2017
- Muskingum County56.3% of reported tests at or above 4 pCi/L, 2017
- Perry County48.9% of reported tests at or above 4 pCi/L, 2017
- Pickaway County81.4% of reported tests at or above 4 pCi/L, 2017
- Pike County56.1% of reported tests at or above 4 pCi/L, 2017
- Preble County62.7% of reported tests at or above 4 pCi/L, 2017
- Richland County62.2% of reported tests at or above 4 pCi/L, 2017
- Ross County67.1% of reported tests at or above 4 pCi/L, 2017
- Seneca County58.9% of reported tests at or above 4 pCi/L, 2017
- Shelby County60.1% of reported tests at or above 4 pCi/L, 2017
- Stark County60.1% of reported tests at or above 4 pCi/L, 2017
- Summit County38.7% of reported tests at or above 4 pCi/L, 2017
- Tuscarawas County66.4% of reported tests at or above 4 pCi/L, 2017
- Union County60.2% of reported tests at or above 4 pCi/L, 2017
- Van Wert County53.8% of reported tests at or above 4 pCi/L, 2017
- Warren County52.5% of reported tests at or above 4 pCi/L, 2017
- Wayne County61.8% of reported tests at or above 4 pCi/L, 2017
- Wyandot County46.3% of reported tests at or above 4 pCi/L, 2017
Zone 2: moderate predicted potential35
- Ashtabula County34.4% of reported tests at or above 4 pCi/L, 2017
- Athens County38.1% of reported tests at or above 4 pCi/L, 2017
- Brown County47.1% of reported tests at or above 4 pCi/L, 2017
- Clermont County50.0% of reported tests at or above 4 pCi/L, 2017
- Cuyahoga County21.7% of reported tests at or above 4 pCi/L, 2017
- Defiance County48.6% of reported tests at or above 4 pCi/L, 2017
- Erie County54.5% of reported tests at or above 4 pCi/L, 2017
- Fulton County45.2% of reported tests at or above 4 pCi/L, 2017
- Gallia County33.3% of reported tests at or above 4 pCi/L, 2017
- Geauga County23.4% of reported tests at or above 4 pCi/L, 2017
- Henry County61.8% of reported tests at or above 4 pCi/L, 2017
- Highland County56.7% of reported tests at or above 4 pCi/L, 2017
- Hocking County53.3% of reported tests at or above 4 pCi/L, 2017
- Jackson County41.7% of reported tests at or above 4 pCi/L, 2017
- Lake County27.2% of reported tests at or above 4 pCi/L, 2017
- Lawrence County30.3% of reported tests at or above 4 pCi/L, 2017
- Lorain County45.4% of reported tests at or above 4 pCi/L, 2017
- Lucas County40.2% of reported tests at or above 4 pCi/L, 2017
- Mahoning County23.4% of reported tests at or above 4 pCi/L, 2017
- Medina County43.4% of reported tests at or above 4 pCi/L, 2017
- Meigs County20.0% of reported tests at or above 4 pCi/L, 2017
- Monroe County58.3% of reported tests at or above 4 pCi/L, 2017
- Morgan County30.0% of reported tests at or above 4 pCi/L, 2017
- Noble County31.0% of reported tests at or above 4 pCi/L, 2017
- Ottawa County40.3% of reported tests at or above 4 pCi/L, 2017
- Paulding County23.1% of reported tests at or above 4 pCi/L, 2017
- Portage County39.3% of reported tests at or above 4 pCi/L, 2017
- Putnam County59.6% of reported tests at or above 4 pCi/L, 2017
- Sandusky County59.2% of reported tests at or above 4 pCi/L, 2017
- Scioto County37.0% of reported tests at or above 4 pCi/L, 2017
- Trumbull County34.6% of reported tests at or above 4 pCi/L, 2017
- Vinton County25.0% of reported tests at or above 4 pCi/L, 2017
- Washington County38.1% of reported tests at or above 4 pCi/L, 2017
- Williams County42.9% of reported tests at or above 4 pCi/L, 2017
- Wood County45.5% of reported tests at or above 4 pCi/L, 2017
Ohio, Cities
Cities in Ohio with their own page
Radon data is published by county, not by city. Each city page sets the figures of the counties the city lies in side by side.
Ohio, Local resources
Local resources in Ohio
Who to ask in Ohio: the state's radon program, test kits and professionals.
Radon Education and Licensing Program
Ohio Department of Health
Ohio’s radon program answers questions about testing, mitigation and the rules where you live.
- Phone
- 614-728-0272
- indoor.radon@odh.ohio.gov
- Licensing of radon professionals
This program licenses companies and persons directly involved with the radon testing and mitigation industry.
Test kits
The program says: Free radon test kits are available for Ohio homeowners.
Radon professionals
6 professionals are listed in Ohio.
Professionals in OhioOhio, Questions
Questions about radon in Ohio
Common questions9 questions, answered from the figures above
Is radon a problem in Ohio?
EPA's Map of Radon Zones places 53 of the 88 Ohio counties it classifies in Zone 1, the highest predicted potential, 35 in Zone 2 and 0 in Zone 3. An EPA radon zone describes predicted potential across a whole county. It is not intended to determine whether any individual home should be tested, and homes with elevated levels occur in all three zones. EPA recommends testing every home regardless of zone, and testing is the only way to know the radon level in a specific building.
How do I get a radon test in Ohio?
EPA says you can test your home yourself or hire a qualified radon test company, and that either approach takes only a small amount of time and effort. The Ohio radon program is the place to ask about certified testers and any test kit offer it runs.
How to test a homeFree and low-cost kits by stateOhio radon program
Who does radon mitigation in Ohio?
Radon411's Ohio directory lists 6 certified radon companies. EPA recommends having a qualified contractor fix a home with a radon problem, because lowering high radon levels takes technical knowledge and special skills, and some states require the work to be done by a licensed or certified professional.
How radon mitigation worksWhat mitigation costsRadon professionals in Ohio
Which Ohio counties are in EPA radon Zone 1?
53 counties are in Zone 1: Adams County, Allen County, Ashland County, Auglaize County, Belmont County, Butler County, Carroll County, Champaign County, and 45 more in the county table on this page. Zone 1 is EPA's class for highest predicted potential, a predicted average indoor screening level greater than 4 pCi/L. A zone is a prediction for a county, not a measurement of any home.
Radon in Adams CountyRadon in Allen CountyRadon in Ashland County
Which Ohio counties have the highest radon?
88 of Ohio's 88 counties have an EPA radon zone published here. Radon411 will not rank counties on data it does not hold, and a zone is a prediction for an area rather than a measurement of any building.
What share of radon tests in Ohio are high?
CDC has published no statewide radon testing statistics for Ohio, so we cannot give a figure. Where CDC does publish one, the percentage describes radon tests reported to CDC, not homes.
Which EPA region is Ohio in?
Ohio is in EPA Region 5: Great Lakes.
Do I need to test my home in Ohio?
Yes, wherever you live in the state. Testing is the only way to know the radon level in a specific building. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. EPA recommends considering a fix when the level is between 2 and 4 pCi/L.
Why does this page show coverage rather than one radon level for Ohio?
A statewide figure averages counties with very different geology and very different numbers of reported tests, so it hides more than it shows. The county report is the level at which the EPA zone, the geologic potential and the reported testing statistics are actually published, which is why the county table above links to every one of them.
What these figures mean if you own, buy, sell or rent
The zone counts on this page describe counties across Ohio. They are predictions for areas, and none of them measures your building.
- How to test a home
If you own your home
Test the lowest lived-in level; a short-term kit screens in days, a long-term kit reflects the year.
- Buying a house: radon guide
If you are buying
Ask for past results and any system's post-mitigation test, and test during the sale.
- Selling a house: radon guide
If you are selling
Testing before you list puts the timing in your hands; disclosure rules differ by state.
- Radon in rental homes
If you rent, or rent out a home
A tenant can test; a fix is the owner's to make, and duties differ by state.
How long a test has to run, under what conditions, and what EPA says a result means: the testing standard, in full.
Ohio, Products
Testing and mitigation products
Whatever the figures for Ohio show, only a test tells you about one home.
Testing
- Short-term test kitsPassive detectors exposed for a few days under closed-building conditions, then analyzed by a lab.
- Long-term test kitsDetectors exposed for more than 90 days, for a closer picture of the annual average.
- Continuous monitorsPowered devices that log radon on a repeating cycle, often used for transaction tests.
- Digital detectorsConsumer devices that display a running radon reading without a lab.
- Water radon testsKits for radon dissolved in well water, analyzed by a lab.
Mitigation
- Mitigation fansThe inline fan that keeps a soil depressurization system running, sized by the installer.
- System indicatorsU-tube manometers and fan alarms that show whether a mitigation system is still working.
- Sealing materialsCrack, joint and sump sealing used alongside a mitigation system, not instead of one.
Ohio / Next steps
What to do next
Learn
Know what radon is
What radon is, how it gets indoors, and why a county zone is not a reading for your home.
Learn about radonTest
Test the building you live in
Short-term or long-term, where the device goes, and closed-house conditions.
How to testFix
Bring a high level down
How a mitigation system works, and the retest that confirms it.
How mitigation worksFind a pro
Hire a certified professional
Measurement and mitigation professionals by state, with their certifications.
Find a professional
Informational. Follow EPA guidance. EPA says all radon tests should be taken for a minimum of 48 hours, with windows and doors closed from 12 hours before a short-term test.