EPA Zone Data 2026
Ohio Radon Map, Levels & Testing Guide
View EPA radon zone classifications for every county in Ohio. Open your county to compare basement test meaning, EPA action thresholds, and when mitigation pricing becomes worth checking.
53
Zone 1
High Risk
High Risk
35
Zone 2
Moderate
Moderate
0
Zone 3
Low Risk
Low Risk
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Browse Counties
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Open your county to see its EPA zone, testing meaning, and the point where mitigation becomes worth pricing.
Adams County
Zone 1
Allen County
Zone 1
Ashland County
Zone 1
Ashtabula County
Zone 2
Athens County
Zone 2
Auglaize County
Zone 1
Belmont County
Zone 1
Brown County
Zone 2
Butler County
Zone 1
Carroll County
Zone 1
Champaign County
Zone 1
Clark County
Zone 1
Clermont County
Zone 2
Clinton County
Zone 1
Columbiana County
Zone 1
Coshocton County
Zone 1
Crawford County
Zone 1
Cuyahoga County
Zone 2
Darke County
Zone 1
Defiance County
Zone 2
Delaware County
Zone 1
Erie County
Zone 2
Fairfield County
Zone 1
Fayette County
Zone 1
Franklin County
Zone 1
Fulton County
Zone 2
Gallia County
Zone 2
Geauga County
Zone 2
Greene County
Zone 1
Guernsey County
Zone 1
Hamilton County
Zone 1
Hancock County
Zone 1
Hardin County
Zone 1
Harrison County
Zone 1
Henry County
Zone 2
Highland County
Zone 2
Hocking County
Zone 2
Holmes County
Zone 1
Huron County
Zone 1
Jackson County
Zone 2
Jefferson County
Zone 1
Knox County
Zone 1
Lake County
Zone 2
Lawrence County
Zone 2
Licking County
Zone 1
Logan County
Zone 1
Lorain County
Zone 2
Lucas County
Zone 2
Madison County
Zone 1
Mahoning County
Zone 2
Marion County
Zone 1
Medina County
Zone 2
Meigs County
Zone 2
Mercer County
Zone 1
Miami County
Zone 1
Monroe County
Zone 2
Montgomery County
Zone 1
Morgan County
Zone 2
Morrow County
Zone 1
Muskingum County
Zone 1
Noble County
Zone 2
Ottawa County
Zone 2
Paulding County
Zone 2
Perry County
Zone 1
Pickaway County
Zone 1
Pike County
Zone 1
Portage County
Zone 2
Preble County
Zone 1
Putnam County
Zone 2
Richland County
Zone 1
Ross County
Zone 1
Sandusky County
Zone 2
Scioto County
Zone 2
Seneca County
Zone 1
Shelby County
Zone 1
Stark County
Zone 1
Summit County
Zone 1
Trumbull County
Zone 2
Tuscarawas County
Zone 1
Union County
Zone 1
Van Wert County
Zone 1
Vinton County
Zone 2
Warren County
Zone 1
Washington County
Zone 2
Wayne County
Zone 1
Williams County
Zone 2
Wood County
Zone 2
Wyandot County
Zone 1
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