Radon in your home significantly increases your family’s risk for developing lung cancer. Reducing this risk is easy:

  1. Test for radon in your home. Do-It-Yourself (DIY) testing is easy and inexpensive. Learn more by reading, “How can I tell if I have radon in my house?” below. 
  2. Fix high radon levels. When fixing is needed there are several things homeowners may be able to Do-It-Yourself (DIY). When professional help is needed, cost is typically comparable to other regular professional home maintenance. Learn more by reading, “What can I do if I have elevated levels?” below.  

Radon is the single largest source of radiation for almost everyone in Washington. Radon is the leading cause of lung cancer among nonsmokers, according to the U.S. Environmental Protection Agency, and the second leading cause behind smoking. It is easy to decrease your risk by conducting an inexpensive in-home radon test and, if necessary, fixing your home.

What is radon?

Radon is a naturally occurring radioactive gas that is invisible, odorless, and tasteless. It comes from the radioactive decay of radium, an element found in most rocks and soils. Radon can enter a building from the ground underneath it and concentrate to tens, or even hundreds, of times the level in outdoor air.

How does radon get in my home?

Radon gas is invisible, odorless, and tasteless. It is created by the radioactive decay of radium, a naturally found element in most rocks and soils. Radon gas emitted from the ground under a building’s foundation can seep up through small gaps and cracks in the foundation and floor, enter the building where it can concentrate to tens, or even hundreds of times the level found naturally in outdoor air.

How can radon affect me?

Radon can cause lung cancer. Longer exposure at higher levels elevates risk further. As radon radioactively decays the particles (photons) released can hit, damage, or even destroy cells. Lung cancer can form when a lung cell is damaged and the cell does not repair itself correctly. The more radon you are exposed to, the greater the opportunity for cell damage, and the greater risk of developing lung cancer. Although smoking is the leading cause of lung cancer, the risk is much higher for an individual who smokes and is exposed to radon. Learn about tobacco-related disease.

How can I tell if I have radon in my house?

Testing your home for radon is the only way to know if you and your family are being exposed to elevated levels of radon. Do-It-Yourself (DIY) test kits are easy-to-use and inexpensive. DIY radon test kits are available at your local hardware store, home improvement store, and online retailers. You may consider hiring a Radon Testing Professional. A Radon Testing Professional is often hired when radon detection is part of a real estate transaction, such as home inspection. Find lists of radon professionals from the National Radon Proficiency Program and the National Radon Safety Board

The Washington State Department of Health Radon Program has a limited supply of free radon test kits. It is important these limited resources support successful testing. When requesting a free radon test kit please commit to carefully following testing instructions and completing the testing process. Free radon test kits can be requested by filling out our online request form. To access and fill out the request form choose the language you prefer to view the form:  English, Russian, Spanish, Vietnamese

What can I do if I have elevated levels?

Test, Fix, Re-Test

If you have tested your home and found elevated radon levels there are some simple things you may be able to Do-It-Yourself (DIY) to help reduce radon levels. Whether you attempt fixes yourself or hire someone else, be sure to conduct a follow-up test when the work is done to ensure the efforts have made the needed impact and reduced radon levels.  

Three simple things help reduce radon levels in your home: 1. Make it harder for radon to get in. Caulk and seal cracks in your basement, foundation, and subfloor. 2. Install a good vapor barrier in your crawl space. The goal is to have a gas-tight barrier between the inside of your home and the ground underneath. 3. Make it easier for radon to go somewhere other than into your house. Ensure foundation vent-blocking is clear and offers unobstructed venting for your home’s crawl space. Increase air exchange with the outside. A home’s radon levels will often test higher when windows and doors are closed such as in winter when the home is being heated, or in summer when the home is being air conditioned. When temperatures are more mild and windows are open, radon gas cannot concentrate in the home like it can when the home is sealed.  

Elevated home radon levels can quickly be reduced by a radon mitigation system installed by a certified radon mitigation specialist. Like most any home feature a radon mitigation system can be installed much easier and at much less expense during a home’s construction. Radon-Resistant New Construction techniques can be used while a new house is being built to help ensure radon is kept outside of your home.

How do I know if I have been exposed to radon?

Medical tests are not available to determine whether you have been exposed to radon. If you are concerned, talk with your doctor. Conducting a simple Do-It-Yourself (DIY) radon test will tell you if there are elevated levels of radon you and your family are being exposed to in your home.  

Where can I find a radon mitigation professional?

If your home has elevated levels of radon, you can hire a certified professional to reduce the amount of radon can enter your home or increase ventilation to remove radon from your home. Find a radon mitigation professional through one of these national certifying organizations:

National Radon Proficiency Program

National Radon Safety Board

These organizations provide the needed education and training for contractors to become certified radon professionals. If you don't find a radon professional listed for your area, speak with a trusted contractor from your area about obtaining this important education, training, and certification. They can access information about training and certification from the links provided above.   

My child's school tested for radon. What should I know?

The risk of developing lung cancer from exposure to radon increases from long-term exposure to radon over a number a years. While we recommend that schools test and reduce exposure to elevated levels of radon, it is even more important to test and reduce exposure to radon where your child will spend the most time over the years, which is typically within the home.

Children's Environmental Health Network Eco-Healthy Child Care (PDF) (Spanish PDF)

I'm a contractor. How do I get certified for radon testing and mitigation?

The National Radon Proficiency Program (NRPP) and the National Radon Safety Board (NRSB) are the national organizations that provide education, training and testing for contractors to become certified for radon testing, radon mitigation system design, and radon mitigation system installation. Washington state does not have a radon training or certification program. These organizations provide the search tools to help Washingtonians find the certified radon professionals they’re looking for: 

National Radon Proficiency Program

National Radon Safety Board

Where can I learn more about radon-resistant construction and mitigation? 

Radon-Resistant Construction Basics and Techniques, EPA 

Builder, Contractor Resources for Radon-Resistant New Construction (RRNC), EPA

Radon Standards of Practice, EPA 

Publications about Radon, EPA 

A Citizen’s Guide to Radon, EPA 

National Radon Proficiency Program (NRPP) 

National Radon Safety Board (NRSB) 

Mapping Radon Exposure in Washington

Radon Maps and Data

Maps and data showing radon risk in our state can be viewed on the Washington Tracking Network.

Visit an environmental health tool to view radon test data for communities and a radon risk map. The tool shows radon and lead risk as topics; we are working to expand topics. You can read information about radon risk and how to get your home tested in the notes section of the online tool.

More Resources

For more information about radon in Washington, contact DOH's radon program at doh.radon@doh.wa.gov or 360-236-3200.

Information about where radon is most common in Washington, along with lung cancer and smoking rates for those areas, is available on the Washington Tracking Network (WTN).

Radon publications and resources, EPA

A Citizen’s Guide to Radon, EPA 

Radon in Washington (PDF)

Radon Awareness: Pacific Northwest and Alaska, EPA Video

Radon and Cancer, American Cancer Society

National Radon Safety Board

Radon-Resistant New Construction for Home Buyers, EPA