Radon and Real Estate If you are buying a home or selling your home, have it tested for radon. For a new home, ask if radon-resistant construction features were used and if the home has been tested. Fix the home if the radon level is 4 picoCuries per liter (pCi/L) or higher. Radon levels less than 4 pCi/L still pose a risk, and in many cases, may be reduced. Take steps to prevent device interference when conducting a radon test.

• The radon test was not performed correctly;
  
  
• The last test is not recent, e.g., within two years;
  
  
• You have renovated or altered your home since you tested; or
  
  
• The buyer plans to live in a lower level of the house than was tested, such as a basement suitable for occupancy but not currently lived in.
  

A buyer may also ask for a new test if your state or local government requires disclosure of radon information to buyers.

If your home has not yet been tested for radon - Have a test taken as soon as possible. If you can, test your home before putting it on the market. You should test in the lowest level of the home which is suitable for occupancy. This means testing in the lowest level that you currently live in or a lower level not currently used, but which a buyer could use for living space without renovations.

The radon test result is important information about your home's radon level. Some states require radon measurement testers to follow a specific testing protocol. If you do the test yourself, you should carefully follow the testing protocol for your area. If you hire a contractor to test your residence, protect yourself by hiring a qualified individual or company.

You can determine a service provider's qualifications to perform radon measurements or to mitigate your home in several ways. Check with your state radon office. Many states require radon professionals to be licensed, certified, or registered. Most states can provide you with a list of knowledgeable radon service providers doing business in the state. In states that don't regulate radon services, ask the contractor if they hold a professional proficiency or certification credential. Such programs usually provide members with a photo-ID card, which indicates their qualification(s) and its expiration date. If in doubt, you should check with their credentialing organization. Alternatively, ask the contractor if they've successfully completed formal training appropriate for testing or mitigation, e.g., a course in radon measurement or radon mitigation.