Radon levels in Ohio

Verified county-level radon indicators are available for 88 Ohio counties. Select a county for its source period and sample details.

High results are most common in Pickaway County (81%) and least common in Cuyahoga County (22%)Share of tests at or above 4 pCi/L by county · Radon test results from laboratories, 2008–2017 · 88 of 88 counties have data
Adams County: 50% of tests at or above 4 pCi/L · 18 testsAllen County: 57% of tests at or above 4 pCi/L · 238 testsAshland County: 63% of tests at or above 4 pCi/L · 340 testsAshtabula County: 34% of tests at or above 4 pCi/L · 314 testsAthens County: 38% of tests at or above 4 pCi/L · 318 testsAuglaize County: 71% of tests at or above 4 pCi/L · 139 testsBelmont County: 45% of tests at or above 4 pCi/L · 697 testsBrown County: 47% of tests at or above 4 pCi/L · 70 testsButler County: 54% of tests at or above 4 pCi/L · 1,953 testsCarroll County: 57% of tests at or above 4 pCi/L · 486 testsChampaign County: 71% of tests at or above 4 pCi/L · 596 testsClark County: 57% of tests at or above 4 pCi/L · 1,447 testsClermont County: 50% of tests at or above 4 pCi/L · 1,363 testsClinton County: 52% of tests at or above 4 pCi/L · 103 testsColumbiana County: 49% of tests at or above 4 pCi/L · 662 testsCoshocton County: 59% of tests at or above 4 pCi/L · 112 testsCrawford County: 60% of tests at or above 4 pCi/L · 210 testsCuyahoga County: 22% of tests at or above 4 pCi/L · 10,092 testsDarke County: 64% of tests at or above 4 pCi/L · 270 testsDefiance County: 49% of tests at or above 4 pCi/L · 70 testsDelaware County: 72% of tests at or above 4 pCi/L · 3,730 testsErie County: 54% of tests at or above 4 pCi/L · 1,651 testsFairfield County: 77% of tests at or above 4 pCi/L · 1,175 testsFayette County: 58% of tests at or above 4 pCi/L · 12 testsFranklin County: 72% of tests at or above 4 pCi/L · 16,142 testsFulton County: 45% of tests at or above 4 pCi/L · 62 testsGallia County: 33% of tests at or above 4 pCi/L · 21 testsGeauga County: 23% of tests at or above 4 pCi/L · 1,469 testsGreene County: 59% of tests at or above 4 pCi/L · 2,602 testsGuernsey County: 44% of tests at or above 4 pCi/L · 117 testsHamilton County: 35% of tests at or above 4 pCi/L · 3,754 testsHancock County: 46% of tests at or above 4 pCi/L · 1,382 testsHardin County: 43% of tests at or above 4 pCi/L · 67 testsHarrison County: 50% of tests at or above 4 pCi/L · 44 testsHenry County: 62% of tests at or above 4 pCi/L · 34 testsHighland County: 57% of tests at or above 4 pCi/L · 67 testsHocking County: 53% of tests at or above 4 pCi/L · 60 testsHolmes County: 64% of tests at or above 4 pCi/L · 67 testsHuron County: 59% of tests at or above 4 pCi/L · 796 testsJackson County: 42% of tests at or above 4 pCi/L · 48 testsJefferson County: 50% of tests at or above 4 pCi/L · 271 testsKnox County: 72% of tests at or above 4 pCi/L · 1,530 testsLake County: 27% of tests at or above 4 pCi/L · 2,349 testsLawrence County: 30% of tests at or above 4 pCi/L · 66 testsLicking County: 71% of tests at or above 4 pCi/L · 4,694 testsLogan County: 74% of tests at or above 4 pCi/L · 755 testsLorain County: 45% of tests at or above 4 pCi/L · 3,307 testsLucas County: 40% of tests at or above 4 pCi/L · 1,381 testsMadison County: 67% of tests at or above 4 pCi/L · 549 testsMahoning County: 23% of tests at or above 4 pCi/L · 666 testsMarion County: 65% of tests at or above 4 pCi/L · 265 testsMedina County: 43% of tests at or above 4 pCi/L · 2,139 testsMeigs County: 20% of tests at or above 4 pCi/L · 20 testsMercer County: 58% of tests at or above 4 pCi/L · 149 testsMiami County: 65% of tests at or above 4 pCi/L · 690 testsMonroe County: 58% of tests at or above 4 pCi/L · 48 testsMontgomery County: 50% of tests at or above 4 pCi/L · 2,922 testsMorgan County: 30% of tests at or above 4 pCi/L · 10 testsMorrow County: 65% of tests at or above 4 pCi/L · 177 testsMuskingum County: 56% of tests at or above 4 pCi/L · 391 testsNoble County: 31% of tests at or above 4 pCi/L · 42 testsOttawa County: 40% of tests at or above 4 pCi/L · 541 testsPaulding County: 23% of tests at or above 4 pCi/L · 13 testsPerry County: 49% of tests at or above 4 pCi/L · 90 testsPickaway County: 81% of tests at or above 4 pCi/L · 183 testsPike County: 56% of tests at or above 4 pCi/L · 57 testsPortage County: 39% of tests at or above 4 pCi/L · 1,661 testsPreble County: 63% of tests at or above 4 pCi/L · 212 testsPutnam County: 60% of tests at or above 4 pCi/L · 94 testsRichland County: 62% of tests at or above 4 pCi/L · 1,327 testsRoss County: 67% of tests at or above 4 pCi/L · 368 testsSandusky County: 59% of tests at or above 4 pCi/L · 649 testsScioto County: 37% of tests at or above 4 pCi/L · 73 testsSeneca County: 59% of tests at or above 4 pCi/L · 540 testsShelby County: 60% of tests at or above 4 pCi/L · 248 testsStark County: 60% of tests at or above 4 pCi/L · 3,317 testsSummit County: 39% of tests at or above 4 pCi/L · 6,486 testsTrumbull County: 35% of tests at or above 4 pCi/L · 425 testsTuscarawas County: 66% of tests at or above 4 pCi/L · 547 testsUnion County: 60% of tests at or above 4 pCi/L · 1,285 testsVan Wert County: 54% of tests at or above 4 pCi/L · 26 testsVinton County: 25% of tests at or above 4 pCi/L · 4 testsWarren County: 53% of tests at or above 4 pCi/L · 2,512 testsWashington County: 38% of tests at or above 4 pCi/L · 349 testsWayne County: 62% of tests at or above 4 pCi/L · 1,074 testsWilliams County: 43% of tests at or above 4 pCi/L · 28 testsWood County: 45% of tests at or above 4 pCi/L · 1,192 testsWyandot County: 46% of tests at or above 4 pCi/L · 320 tests
  • Under 10%
  • 10–20%
  • 20–30%
  • 30–40%
  • 40% or more
  • No data

Counties

CountyTests% ≥ 4 pCi/LMedian (pCi/L)EPA zone (1993)Source
Adams County1850%3.8Zone 1Radon test results from laboratories through 2017
Allen County23857%5.0Zone 1Radon test results from laboratories through 2017
Ashland County34063%5.4Zone 1Radon test results from laboratories through 2017
Ashtabula County31434%2.5Zone 2Radon test results from laboratories through 2017
Athens County31838%3.1Zone 2Radon test results from laboratories through 2017
Auglaize County13971%6.5Zone 1Radon test results from laboratories through 2017
Belmont County69745%3.6Zone 1Radon test results from laboratories through 2017
Brown County7047%3.3Zone 2Radon test results from laboratories through 2017
Butler County1,95354%4.4Zone 1Radon test results from laboratories through 2017
Carroll County48657%4.8Zone 1Radon test results from laboratories through 2017
Champaign County59671%6.8Zone 1Radon test results from laboratories through 2017
Clark County1,44757%4.9Zone 1Radon test results from laboratories through 2017
Clermont County1,36350%4.0Zone 2Radon test results from laboratories through 2017
Clinton County10352%4.2Zone 1Radon test results from laboratories through 2017
Columbiana County66249%3.8Zone 1Radon test results from laboratories through 2017
Coshocton County11259%5.1Zone 1Radon test results from laboratories through 2017
Crawford County21060%4.7Zone 1Radon test results from laboratories through 2017
Cuyahoga County10,09222%2.0Zone 2Radon test results from laboratories through 2017
Darke County27064%5.6Zone 1Radon test results from laboratories through 2017
Defiance County7049%3.8Zone 2Radon test results from laboratories through 2017
Delaware County3,73072%6.4Zone 1Radon test results from laboratories through 2017
Erie County1,65154%4.4Zone 2Radon test results from laboratories through 2017
Fairfield County1,17577%7.4Zone 1Radon test results from laboratories through 2017
Fayette County1258%5.5Zone 1Radon test results from laboratories through 2017
Franklin County16,14272%6.8Zone 1Radon test results from laboratories through 2017
Fulton County6245%3.1Zone 2Radon test results from laboratories through 2017
Gallia County2133%3.0Zone 2Radon test results from laboratories through 2017
Geauga County1,46923%2.4Zone 2Radon test results from laboratories through 2017
Greene County2,60259%4.9Zone 1Radon test results from laboratories through 2017
Guernsey County11744%3.6Zone 1Radon test results from laboratories through 2017
Hamilton County3,75435%2.8Zone 1Radon test results from laboratories through 2017
Hancock County1,38246%3.7Zone 1Radon test results from laboratories through 2017
Hardin County6743%3.4Zone 1Radon test results from laboratories through 2017
Harrison County4450%4.1Zone 1Radon test results from laboratories through 2017
Henry County3462%5.3Zone 2Radon test results from laboratories through 2017
Highland County6757%4.8Zone 2Radon test results from laboratories through 2017
Hocking County6053%4.0Zone 2Radon test results from laboratories through 2017
Holmes County6764%5.8Zone 1Radon test results from laboratories through 2017
Huron County79659%4.9Zone 1Radon test results from laboratories through 2017
Jackson County4842%3.3Zone 2Radon test results from laboratories through 2017
Jefferson County27150%3.9Zone 1Radon test results from laboratories through 2017
Knox County1,53072%8.1Zone 1Radon test results from laboratories through 2017
Lake County2,34927%2.4Zone 2Radon test results from laboratories through 2017
Lawrence County6630%2.5Zone 2Radon test results from laboratories through 2017
Licking County4,69471%7.0Zone 1Radon test results from laboratories through 2017
Logan County75574%7.9Zone 1Radon test results from laboratories through 2017
Lorain County3,30745%3.6Zone 2Radon test results from laboratories through 2017
Lucas County1,38140%3.0Zone 2Radon test results from laboratories through 2017
Madison County54967%5.7Zone 1Radon test results from laboratories through 2017
Mahoning County66623%2.5Zone 2Radon test results from laboratories through 2017
Marion County26565%6.4Zone 1Radon test results from laboratories through 2017
Medina County2,13943%3.5Zone 2Radon test results from laboratories through 2017
Meigs County2020%2.7Zone 2Radon test results from laboratories through 2017
Mercer County14958%5.1Zone 1Radon test results from laboratories through 2017
Miami County69065%6.1Zone 1Radon test results from laboratories through 2017
Monroe County4858%5.0Zone 2Radon test results from laboratories through 2017
Montgomery County2,92250%4.0Zone 1Radon test results from laboratories through 2017
Morgan County1030%3.3Zone 2Radon test results from laboratories through 2017
Morrow County17765%5.7Zone 1Radon test results from laboratories through 2017
Muskingum County39156%4.9Zone 1Radon test results from laboratories through 2017
Noble County4231%2.2Zone 2Radon test results from laboratories through 2017
Ottawa County54140%2.9Zone 2Radon test results from laboratories through 2017
Paulding County1323%3.2Zone 2Radon test results from laboratories through 2017
Perry County9049%3.8Zone 1Radon test results from laboratories through 2017
Pickaway County18381%9.5Zone 1Radon test results from laboratories through 2017
Pike County5756%4.5Zone 1Radon test results from laboratories through 2017
Portage County1,66139%3.2Zone 2Radon test results from laboratories through 2017
Preble County21263%5.5Zone 1Radon test results from laboratories through 2017
Putnam County9460%4.8Zone 2Radon test results from laboratories through 2017
Richland County1,32762%5.2Zone 1Radon test results from laboratories through 2017
Ross County36867%7.0Zone 1Radon test results from laboratories through 2017
Sandusky County64959%5.0Zone 2Radon test results from laboratories through 2017
Scioto County7337%2.7Zone 2Radon test results from laboratories through 2017
Seneca County54059%4.9Zone 1Radon test results from laboratories through 2017
Shelby County24860%5.2Zone 1Radon test results from laboratories through 2017
Stark County3,31760%4.9Zone 1Radon test results from laboratories through 2017
Summit County6,48639%3.1Zone 1Radon test results from laboratories through 2017
Trumbull County42535%2.9Zone 2Radon test results from laboratories through 2017
Tuscarawas County54766%5.6Zone 1Radon test results from laboratories through 2017
Union County1,28560%4.8Zone 1Radon test results from laboratories through 2017
Van Wert County2654%4.3Zone 1Radon test results from laboratories through 2017
Vinton County425%1.9Zone 2Radon test results from laboratories through 2017
Warren County2,51253%4.2Zone 1Radon test results from laboratories through 2017
Washington County34938%3.1Zone 2Radon test results from laboratories through 2017
Wayne County1,07462%4.9Zone 1Radon test results from laboratories through 2017
Williams County2843%3.3Zone 2Radon test results from laboratories through 2017
Wood County1,19245%3.5Zone 2Radon test results from laboratories through 2017
Wyandot County32046%3.6Zone 1Radon test results from laboratories through 2017

Test your home

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