Radon is the number one cause of lung cancer among non-smokers. For children, radon and second-hand smoke are the biggest risk factors for development of lung cancer. Smokers who are exposed to radon have a much higher risk of lung cancer. Detecting radon is different from a smoke detector or carbon monoxide detector in your home. You have to test your home for radon with a radon test kit. It is a colorless, odorless, invisible gas that occurs naturally in Maryland and many other states. 

Why is this Important to You?1

  •         There is no known safe level of radon.
  •          Radon may be found in all types of homes and buildings.
  •          Exposure to radon can cause lung cancer in smokers and non-smokers alike. 

Radon and the Environment1

Radon is naturally occurring in earth and rock that seeps into buildings from the surrounding soil. The amount of radon in the soil depends on soil chemistry, which varies from one house to the next. The amount of radon that escapes from the soil to enter the house depends on the weather, soil porosity, soil moisture, and the amount the home can take up. 

Radon in Maryland

The map below shows radon levels measured in homes by ZIP code in Maryland from 2005-2016.  The U.S. Environmental Protection Agency (EPA) recommends testing all homes for radon, and fixing homes if their levels are higher than 4 picocuries per liter (pCi/L).

What Can You Do?

The most important thing you can do is to become educated about radon and have your home tested. You may purchase radon test kits online or at your local hardware store. You may also click here to Find a Radon Test Kit or Measurement and Mitigation Professional. 

Radon Testing1

The following is an excerpt from EPA's Citizen's Guide to Radon

EPA Recommends the Following Testing Steps: 

Step 1: Take a short-term test. If your result is 4 pCi/L. or higher*, take a follow-up test (Step 2) to be sure. 

Step 2: Follow up with either a long-term test or a second short-term test: 

Step 3:

  •        If you followed up with a long-term test: Fix your home if your long-term test result is 4pCi/L or more*.
  •          If you followed up with a second short-term test: The higher your short-term results, the more certain you can be that you should fix your home. 

Radon Information for Homebuyers and Sellers6

For more information on Real Estate Resources 

For more information on Home Buyer’s/Seller’s Guide to Radon 

For more information on Radon Protection: Buying a Newly Built Home 

Radon-Resistant New Construction4,6

Radon-Resistant New Construction (RRNC) use simple technology and radon reduction techniques to help keep radon from entering a home by directing the radon gas outdoors. It is more cost-effective to include radon-resistant techniques while build a home, rather than retrofitting an existing home. 

See attached for Radon Protection: Building a Home 

See attached for a Radon-Resistant New Construction checklist 

See attached for Building a New Home, Have You Considered Radon?​ 

See attached for Builders and Contractors Resources for RRNC 

See attached for Directory of Builders Using Radon-Resistant New Construction (RRNC)

Radon in Rental Properties3

  • Find out whether the building you live in has been tested for radon.
  • If your building has not been tested, ask the building owner to test, or test your own dwelling. 

For more information for Radon Guide for Tenants\

What if my Home has High Radon Levels?3

Fixing a radon problem usually involves repairs to the building. These repairs are generally authorized by the owner, not the tenant. As a tenant, take the following steps to ensure the problem is fixed. 

  • 1      Inform the building owner in writing if your radon testing shows high radon levels.
  • 2      If the owner performs additional radon testing, you can ask for the test results.
  • 3      If you live in an apartment building, you can share your radon information with other residents. 

For more information call the DHMH hotline at 1-866-703-3266 

Radon in Schools2

If you don't know your school’s radon level, you should think about discussing with your school’s officials about having your school tested for radon. 

Information on how to manage radon in schools may be found here.

More Information

The National Radon Safety Board and The National Radon Proficiency Program (NRPP) can help consumers find a certified radon professional and help professionals become certified


[1] 2016_a_citizens_guide_to_radon.pdf. (n.d.). Retrieved from https://www.epa.gov/sites/production/files/2016


[2] US EPA, O. (n.d.). Radon in Schools [Overviews and Factsheets]. Retrieved February 1, 2017, from https://www.epa.gov/radon/radon-schools

[3] U.S. EPA, O. (n.d.). “A Radon Guide for Tenants”. Retrieved 3 March, 2017, from https://www.epa.gov/sites/production/files/2014-08/documents/tenants_guide.pdf

[4] State of Connecticut. Department of Public Health. (2017). Radon – Resistant New Construction. from http://www.ct.gov/dph/cwp/view.asp?a=3140&q=387610

[5] https://www.youtube.com/watch?v=aYu71niQvJk

[6] U.S. Environmental Protection Agency. (2017). Radon from https://www.epa.gov/radon