EPA Zone Data 2026
Illinois Radon Map, Levels & Testing Guide
View EPA radon zone classifications for every county in Illinois. Open your county to compare basement test meaning, EPA action thresholds, and when mitigation pricing becomes worth checking.
56
Zone 1
High Risk
High Risk
43
Zone 2
Moderate
Moderate
3
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
Bond County
Zone 2
Boone County
Zone 1
Brown County
Zone 1
Bureau County
Zone 1
Calhoun County
Zone 1
Carroll County
Zone 1
Cass County
Zone 1
Champaign County
Zone 1
Christian County
Zone 2
Clark County
Zone 2
Clay County
Zone 2
Clinton County
Zone 2
Coles County
Zone 1
Cook County
Zone 2
Crawford County
Zone 2
Cumberland County
Zone 2
De Witt County
Zone 1
DeKalb County
Zone 1
Douglas County
Zone 1
DuPage County
Zone 2
Edgar County
Zone 1
Edwards County
Zone 2
Effingham County
Zone 2
Fayette County
Zone 2
Ford County
Zone 1
Franklin County
Zone 2
Fulton County
Zone 1
Gallatin County
Zone 2
Greene County
Zone 1
Grundy County
Zone 1
Hamilton County
Zone 2
Hancock County
Zone 1
Hardin County
Zone 2
Henderson County
Zone 1
Henry County
Zone 1
Iroquois County
Zone 1
Jackson County
Zone 2
Jasper County
Zone 2
Jefferson County
Zone 2
Jersey County
Zone 1
Jo Daviess County
Zone 1
Johnson County
Zone 2
Kane County
Zone 1
Kankakee County
Zone 2
Kendall County
Zone 1
Knox County
Zone 1
LaSalle County
Zone 1
Lake County
Zone 2
Lawrence County
Zone 2
Lee County
Zone 1
Livingston County
Zone 1
Logan County
Zone 1
Macon County
Zone 1
Macoupin County
Zone 2
Madison County
Zone 2
Marion County
Zone 2
Marshall County
Zone 1
Mason County
Zone 1
McDonough County
Zone 1
McHenry County
Zone 2
McLean County
Zone 1
Menard County
Zone 1
Mercer County
Zone 1
Monroe County
Zone 2
Montgomery County
Zone 2
Morgan County
Zone 1
Moultrie County
Zone 1
Ogle County
Zone 1
Peoria County
Zone 1
Perry County
Zone 2
Piatt County
Zone 1
Pike County
Zone 1
Pope County
Zone 2
Putnam County
Zone 1
Randolph County
Zone 2
Richland County
Zone 2
Rock Island County
Zone 1
Saline County
Zone 2
Sangamon County
Zone 1
Schuyler County
Zone 1
Scott County
Zone 1
Shelby County
Zone 2
St. Clair County
Zone 2
Stark County
Zone 1
Stephenson County
Zone 1
Tazewell County
Zone 1
Union County
Zone 2
Vermilion County
Zone 1
Wabash County
Zone 2
Warren County
Zone 1
Washington County
Zone 2
Wayne County
Zone 2
White County
Zone 2
Whiteside County
Zone 1
Will County
Zone 2
Williamson County
Zone 2
Winnebago County
Zone 1
Woodford County
Zone 1
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