Radon Testing and Mitigation

Radon Testing

The amount of radon in the air is measured in “picocuries per liter of air” or pCi/L.  There are many different vendors of low-cost do it yourself radon test kits that are available in retail stores or on-line. Indoor radon usually reaches its maximum concentration during the coldest winter months.  The lowest livable level of the structure should always be tested because that is where the highest radon levels in the structure are typically found.  An area that is already finished or easily could be finished is considered livable. Crawlspaces, garages and cellars that lack utilities/ sufficient headspace or have exposed dirt/rock are not considered livable. Short term testing (2-7 days) should NOT be performed during unusually severe storms because heavy precipitation, high sustained winds and powerful low pressure systems might all cause temporary high spikes in indoor radon levels. Every section of the home that is in contact with the ground should be tested, especially different foundation types that are on different elevations. Frequently occupied rooms (like bedrooms & family rooms) should be tested. The test device should be placed at least 20 inches above the floor and well away from outside walls, fans, windows, areas of high humidity (like bathrooms & laundry rooms) or openings in the floor (like sumps and plumbing cut-outs).

All radon test devices must be approved by either the NRSB or NRPP (see below). If you prefer, and especially if you are buying or selling a home, you may hire a trained professional to perform radon testing for you.  Depending on the test device used, a professional radon test will usually cost between $100-200. Radon in real estate transactions is discussed in EPA’s “Home Buyer’s and Seller’s Guide to Radon”

 How to Order Discounted Radon Test Kits

VDH is making a limited supply of short-term, do-it-yourself radon test kits available for only a $4 shipping fee.  This offer will only be available between the dates of October 1 and April 30 each year or until the available supply of test kits runs out. You may order your test kits at: http://www.vdhradon.org

Radon Mitigation

A variety of methods are used to reduce radon in your home.  In some cases, sealing cracks in floors and walls may help to reduce radon.  In other cases, simple systems using pipes and fans may be used. The most common type of system is called “sub-slab depressurization” and does not require major changes to your home.  These systems remove radon gas from below the foundation before it can enter the home.  The right system depends on the design of your home and on other factors. Ways to reduce radon in your home are discussed in EPA’s “Consumer’s Guide to Radon Reduction”. The cost of making repairs to reduce radon depends on how your home was built and the extent of the radon problem.  A typical sub slab system may cost $800-1200 while crawl spaces or homes with multiple sections that need to be mitigated may cost $2000 or more.

Radon Testing & Mitigation Guidance Documents

Although not yet referenced in the Virginia Code, both VDH and EPA recommend that radon professionals follow the testing and mitigation standards co-written by the American National Standards Institute (ANSI) and the American Association of Radiation Scientists and Technologists (AARST). These standards cover all types of buildings and they may be viewed (but not copied) here: https://standards.aarst.org/.  These are the best available radon testing and mitigation standards and they are updated/revised every 3 years.

Radon Professional Certification 

The Virginia Code requires that all professional radon testers and radon mitigators operating in the Commonwealth be currently certified by either the National Radon Safety Board (NRSB) or the National Radon Proficiency Program (NRPP). The lists of currently certified radon professionals found on these websites may be searched by zip code to find those professionals who are located closest to you.


.   NRSB



Office of Radiological Health | 109 Governor Street, 7th Floor | Richmond, VA 23219

Telephone (804) 864-8150 | Fax: (804) 864-8155