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Ohio Radon Map and Levels by County

Ohio's counties span EPA Zones 1 and 2. Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

Predicted
53 of 88counties in Zone 1, EPA's highest radon zone
Measured
By countyCDC publishes Ohio's test figures by county: 88 of 88 counties have one.
Your home
Test to knowNo area figure here is a reading of your home.
How to test this homeFind a certified tester

The data

Ohio, At a glance

Ohio at a glance

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.

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

CDC test figures, county by county

CDC publishes Ohio's radon test figures by county: 88 of its 88 counties have one. Each one's share is in the county list.

Ohio, Counties

Ohio counties by EPA zone

Predicted

Ohio's radon map, then all 88 counties by the zone EPA predicts for each, highest reported share of tests at or above 4 pCi/L first. Each has its own report.

Ohio radon map by county: EPA radon zones. Map of Ohio's 88 counties shaded by EPA radon zone: Zone 1 in red-orange, Zone 2 in amber. 53 in Zone 1, 35 in Zone 2, 0 in Zone 3.
Ohio radon map by countyEPA radon zones for Ohio's counties: 53 counties in Zone 1, 35 counties in Zone 2, 0 counties in Zone 3.Predicted potential for each county, not a reading of any home. Homes with elevated levels of radon have been found in all three zones.

Zone 1: highest predicted potential53

Local help

Ohio, Local resources

Local resources in Ohio

Who to ask in Ohio: its radon program, test kits and professionals.

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.

Radon Action Brief

National Radon Action MonthPre-sale

The radon brief for your Ohio county, in one dated file.

  • Your area's radon record, explained.
  • Your plan to test this week.
  • Fix costs and pros near you.

Save 64%Sale price: $8.99Price after the sale: $25Ends Jan 31Then $25

Get your Ohio county's BriefSee a free sample

Area data, not a test of the building.

What it means

Ohio, Questions

Questions about radon in Ohio

Common questions

9 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.

Ohio on the radon mapRadon levels by state

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 481 radon businesses for testing, mitigation or both, each with the licensing list it was read from. 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.

If you own, buy, sell or rent

What these figures mean for each reader, with the guide that covers it

The zone counts on this page describe counties across Ohio. They are predictions for areas, and none of them measures your building.

Ohio in figures

The figures above, said in words

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

      Predicted

      EPA 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 Radon411

      60% 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

    Measured

    CDC 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 (16,142 tests over 2008 to 2017, laboratory), Cuyahoga County (10,092 tests over 2008 to 2017, laboratory) and Summit County (6,486 tests over 2008 to 2017, laboratory).

  • 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, Westerville, Akron, Parma, Canton and Lancaster.

Products

Ohio, Products

Testing and mitigation products

Whatever the figures for Ohio show, only a test tells you about one home.

Test kits and monitors42

See all products

As an Amazon Associate, Radon411 earns from qualifying purchases.

Best radon monitors for Ohio homes, compared

Testing

5

Mitigation

3

Explore

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, Next steps

What to do next

  1. LearnKnow what radon isWhat radon is, how it gets indoors, and why a county zone is not a reading for your home.Learn about radon
  2. TestTest the building you live inShort-term or long-term, where the device goes, and closed-house conditions.How to test
  3. FixBring a high level downHow a mitigation system works, and the retest that confirms it.How mitigation works
  4. Find a proHire a certified professionalMeasurement 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.