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EPA Map of Radon Zones

The purpose of this map is to assist National, State, and local organizations to target their resources and to implement radon-resistant building codes. This map is not intended to be used to determine if a home in a given zone should be tested for radon. Homes with elevated levels of radon have been found in all three zones. All homes should be tested regardless of geographic location. Important points to note:

Find state-specific radon information
(state radon coordinator, state information, zone maps (including full page versions of the state maps), radon-resistant new construction, regional contact information, radon action month, and more.)

  • All homes should test for radon, regardless of geographic location or zone designation. How do I test my home?
  • There are many thousands of individual homes with elevated radon levels in Zone 2 and 3. Elevated levels can be found in Zone 2 and Zone 3 counties.
  • EPA also recommends that this map be supplemented with any available local data in order to further understand and predict the radon potential of a specific area. For more information, contact your state radon coordinator. Click Here for a US map (where you can select your state) to see if your state has more detailed information available.
  • The map should not be used in lieu of testing during real estate transactions.

Still have questions regarding radon?

Scan our Frequent Questions for more information regarding radon.

Find all of our Radon publications and resources at www.epa.gov/radon/pubs.

The Map was developed using five factors to determine radon potential:

  1. indoor radon measurements;
  2. geology;
  3. aerial radioactivity;
  4. soil permeability; and
  5. foundation type.

Radon potential assessment is based on geologic provinces. Radon Index Matrix is the quantitative assessment of radon potential. Confidence Index Matrix shows the quantity and quality of the data used to assess radon potential. Geologic Provinces were adapted to county boundaries for the Map of Radon Zones. To order the U.S. Geological Survey radon potential books, organized by region, with individual chapters for each state, see http://energy.cr.usgs.gov/radon/grpinfo.html

About the Map

Sections 307 and 309 of the Indoor Radon Abatement Act of 1988 (IRAA) directed EPA to list and identify areas of the U.S. with the potential for elevated indoor radon levels. EPA's Map of Radon Zones assigns each of the 3,141 counties in the U.S. to one of three zones based on radon potential.

What do the colors mean?

Zone 1 counties have a predicted average indoor radon screening level greater than 4 pCi/L (picocuries per liter) (red zones) Highest Potential
Zone 2 counties have a predicted average indoor radon screening level between 2 and 4 pCi/L (orange zones) Moderate Potential
Zone 3 counties have a predicted average indoor radon screening level less than 2 pCi/L (yellow zones) Low Potential

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EPA Map of Radon Zones

Click on the image for a full page printable version
EPA Map of Radon Zones (PDF) (1 page, 379 K, about PDF)

Test Your Home for Radon — It's Easy and Inexpensive

The U.S. Surgeon General and EPA recommend that all homes be tested. Read about radon health risks.

Fix your home if you have a radon level of 4 pCi/L or more.
You can test your home yourself or hire a professional. Find a radon service professional near you.

If you have further questions about Radon, please call your State Radon Contact.

Radon Hotline

1-800-SOSRADON (1-800-767-7236) | Fax: (785) 532-6952 | E-mail: Radon@ksu.edu | www.sosradon.org exiting EPA
Read more about all the services Kansas State University provides. Learn more about radon resources

Read "A Citizen's Guide To Radon: The Guide to Protecting Yourself and Your Family from Radon
Buying or Selling a Home? Read the "Home Buyer's and Seller's Guide to Radon"
Read A Consumer's Guide to Radon Reduction: How to Fix Your Home
Health Risks Hotlines & Resources Indoor airPLUS Kids, Students and Teachers Map of Radon Zones Media Campaigns National Radon Action Month Radon-Resistant New Construction Radon and Real Estate Radon in Drinking Water Radon Leaders Saving Lives State Radon Contacts State Indoor Radon Grants Test or Fix Your Home Webinars Indoor Air Quality

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