Radon test results by state

Where each state publishes the radon test results it has collected, by county, ZIP code, or town. The numbers live on the state's page; this page only points to it.

Checked October 5, 2026
State	Publishes results	Format	Years covered	Updated	Source
Alabama	Yes: by ZIP code				Source: Alabama Department of Public Health
Alaska	Not confirmed
Arizona	Not confirmed
Arkansas	Not confirmed
California	Yes: by ZIP code				Source: California Geological Survey
Colorado	Yes: by county		Years covered: 2005 to 2017		Source: Colorado Department of Public Health and Environment
Connecticut	Not confirmed
Delaware	Not confirmed
District of Columbia	Not confirmed
Florida	Yes: by county	Format: PDF		Updated: 01-17-17	Source: Florida Department of Health (PDF)
Georgia	Yes: by county	Format: Map			Source: University of Georgia Extension
Hawaii	Not confirmed
Idaho	Not confirmed
Illinois	Yes: by county and ZIP code	Format: Map	Years covered: 2003 - 2019		Source: Illinois Emergency Management Agency and Office of Homeland Security
Indiana	Not confirmed
Iowa	Not confirmed
Kansas	Yes: by county	Format: Map	Years covered: through June of 2018		Source: Kansas Radon Program
Kentucky	Not confirmed
Louisiana	Not confirmed
Maine	Yes: by county and town	Format: Map			Source: Maine Center for Disease Control and Prevention
Maryland	Yes: by ZIP code	Format: Map	Years covered: 2005-2016		Source: Maryland Department of Health
Massachusetts	Not confirmed
Michigan	Yes: by county and ZIP code	Format: Map			Source: Michigan Department of Environment, Great Lakes, and Energy
Minnesota	Yes: by county	Format: Map	Years covered: 2010-2020		Source: Minnesota Department of Health
Mississippi	No				Source: Mississippi State Department of Health
Missouri	Not confirmed
Montana	Not confirmed
Nebraska	Yes: by county	Format: Map	Years covered: October 1, 2018 to September 30, 2023		Source: Nebraska Department of Health and Human Services
Nevada	Not confirmed
New Hampshire	Not confirmed
New Jersey	Not confirmed
New Mexico	Yes: by county				Source: New Mexico Environment Department
New York	Yes: by county and town		Years covered: Beginning 1987		Source: New York State Department of Health
North Carolina	Yes: by county	Format: Map			Source: North Carolina Department of Health and Human Services
North Dakota	Not confirmed
Ohio	Yes: by county and ZIP code	Format: Dashboard	Years covered: 2010-present	Updated: monthly	Source: Ohio Department of Health
Oklahoma	Not confirmed
Oregon	Not confirmed
Pennsylvania	Yes: by ZIP code				Source: Pennsylvania Department of Environmental Protection
Rhode Island	Not confirmed
South Carolina	Yes: by county	Format: Map	Years covered: through June 30, 2022		Source: South Carolina Department of Environmental Services
South Dakota	No				Source: South Dakota Department of Agriculture and Natural Resources
Tennessee	Yes: by county		Years covered: 2023		Source: Tennessee Department of Health
Texas	Not confirmed
Utah	Yes: by county and ZIP code	Format: Map	Years covered: 2006 to 2021		Source: Utah Department of Health and Human Services
Vermont	Not confirmed
Virginia	Not confirmed
Washington	Not confirmed
West Virginia	Not confirmed
Wisconsin	Yes: by ZIP code	Format: Map			Source: Wisconsin Department of Health Services
Wyoming	Not confirmed

Published results

Alabama

“Click the Alabama Radon Zones map to look up results by your zip code.”¹

“The California Department of Public Health (CDPH) Radon Program collects radon test data for buildings throughout the state and maintains a radon database, California Radon Measurements by Zip Code”²

Colorado

“The first measure is the average indoor radon value for a county. The second measure is the percent of radon test measurements over the EPA action limit, 4 pCi/L.”³

Florida

“About 99% of the radon tests performed in Florida occurred in the 25 counties highlighted in the map above.”⁴

Georgia

“Radon Levels in Georgia Counties”⁵

“Percentage of homes tested with levels 4.0 pCi/L and above”⁵

Illinois

“Measurements can be found by either County or Zip Code.”⁶

Kansas

“This map has been produced using data collected by KDHE through June of 2018.”⁷

Maine

“Data represent households tested for radon in air, summarized by geographic area (State, County, Town), and for rental and non-rental dwellings.”⁸

Maryland

“The map below shows radon levels measured in homes by ZIP code in Maryland from 2005-2016.”⁹

Michigan

“This map shows radon information for first time tests, without active radon mitigation systems, by ZIP code.”¹⁰

“Percentage of Elevated Radon Test Results by County”¹¹

Minnesota

“The 95th percentile, median, geometric average, and arithmetic average radon levels in pCi/L, by county.”¹²

Nebraska

“The map below compares the average pre-mitigation radon levels in Nebraska counties by using data from October 1, 2018 to September 30, 2023.”¹³

New Mexico

“Radon Levels by County”¹⁴

New York

“Radon Test Results By Town: Beginning 1987”¹⁵

“You can view maps, graphs and tables of radon test results in your county.”¹⁶

North Carolina

“The following map shows the highest level of radon measured in each county.”¹⁷

Ohio

“Key statistics calculated from radon levels measured in homes organized by zip code and county.”¹⁸

“Map data is from 2010-present, as reported by Ohio licensed radon professionals, and data is updated monthly.”¹⁹

Pennsylvania

“A search for radon test data by zip code can be done here:”²⁰

South Carolina

“View a map of S.C. test results by county”²¹

“This map is current through June 30, 2022.”²¹

Tennessee

“Radon Levels by County”²²

“Average Radon Level of Pre-Mitigation Tests, 2023”²³

Utah

“Radon test results (median and maximum)”²⁴

“Map of all ZIP codes”²⁴

“By county, by year”²⁴

Wisconsin

“To view more years of data and data at the zip code level, visit the Wisconsin Interactive Radon Map”²⁵

No published results

Mississippi

“The EPA has published a map characterizing all Mississippi counties. If you identify the county, we can tell you how EPA characterized that county.”²⁶

South Dakota

“The map below shows the geologic radon potential for the United States. These maps should not be used as a substitute for an actual radon test.”²⁷

Not confirmed

The page checked for each state, October 5, 2026:

Alaska: Alaska Division of Geological and Geophysical Surveys
Arizona: Arizona Department of Health Services
Arkansas: Arkansas Department of Health
Connecticut: Connecticut Department of Public Health, Radon Program
Delaware: Delaware Health and Social Services (did not load)
District of Columbia: Department of Energy and Environment, Radon Map
Hawaii: Hawaii State Department of Health, Indoor and Radiological Health Branch
Idaho: Idaho Department of Health and Welfare
Indiana: Indiana Department of Health, Radon Dashboard
Iowa: Iowa Department of Health and Human Services
Kentucky: Kentucky Board of Radon Safety
Louisiana: Louisiana Department of Environmental Quality
Massachusetts: Massachusetts Department of Public Health (did not load)
Missouri: Missouri Department of Health and Senior Services, Radon Test Results, 2 to 4 pCi/L
Montana: Montana Department of Environmental Quality, Radon Control Program
Nevada: University of Nevada, Reno Extension, Nevada Radon Education Program
New Hampshire: New Hampshire Department of Health and Human Services (did not load)
New Jersey: New Jersey Department of Environmental Protection, radon map
North Dakota: North Dakota Department of Environmental Quality
Oklahoma: Oklahoma Department of Environmental Quality
Oregon: Oregon Health Authority
Rhode Island: Rhode Island Department of Health (did not load)
Texas: Texas Tech University, Texas Radon Information
Vermont: Vermont Department of Health
Virginia: Virginia Department of Health, Indoor Radon Program
Washington: Washington State Department of Health
West Virginia: West Virginia Office of Environmental Health Services, Radiation, Toxics and Indoor Air Division
Wyoming: Wyoming Department of Health

Sources

Checked October 5, 2026.

Find a test kit near you. What your result means.

Health facts on this page come from the agencies linked here. About this directory.