What is Radon?
Radon is a naturally occurring radioactive gas created by the natural breakdown of uranium and radium. Radon typically enters a home or other structure by coming up through the ground into the air and then through cracks or holes in the home’s foundation. It can also enter the home through cracks in walls, construction joints, gaps around services pipes and even the water supply (especially well water). This gas can then accumulate to concentrations that can increase the risk of lung cancer. According to the US Surgeon General, radon is the second leading cause of lung cancer with the US Environmental Protection Agency estimating that it causes approximately 21,000 lung cancer deaths annually. It is especially dangerous because it can only be detected by specialized testing as it is colorless, odorless, and tasteless.

Where is Radon Found?
Radon can be found in every state although levels do vary with the EPA breaking areas down by zone with Zone 1 having the highest potential for elevated indoor radon levels and Zone 3 the lowest. The EPA map can be found here. Counties in southeastern Pennsylvania and New Castle County in Delaware have large concentrations of areas in Zone 1.

However, high radon levels can be found in any house regardless of zone ranking and therefore, zone data should not be used as a determining factor in whether a house should be tested. In fact, radon levels can vary from house to house on the same street. For this reason, the U.S. Surgeon General recommends that all homes in the US be tested for radon.

  • Note: Pennsylvania and Delaware have both published radon guides for their citizens which provide more information for each state. Visit Pennsylvania’s site here and Delaware’s here.

Measuring Radon

Testing is the only way to determine the level of radon in your home. The amount of radon in the air is measured in pCi/L (picocuries per liter of air). The EPA states that the average indoor radon level is estimated to be about 1.3 pCi/L, and about 0.4 pCi/L of radon is normally found in the outside air. It is recommended that you fix the home if the radon level is 4 pCi/L or higher. Radon levels less than 4 pCi/L still pose a risk and, in many cases, may be reduced.

Mitigating Radon
If a home tests high for radon, don’t panic – radon problems can be fixed! Radon mitigation systems can be installed to draw the radon-laden soil gas from beneath the foundation and exhaust it outside of the structure, far enough away from windows and other openings. Make sure you use a qualified contractor to install the system as there are radon mitigation standards set by the EPA. These systems are generally inexpensive to install; however costs can vary and are based on the design of the home and not the amount of radon present.

Radon and Real Estate Transactions
Radon tests are now commonly standard practice in real estate transactions and are often required for certain types of home loans. The EPA recommends:

  • If you are buying or selling a 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
  • Radon tests can be conducted at any time, however, winter is the best time to test for radon because doors and windows are typically closed and tightly sealed, producing the most accurate results

In summary, any home, regardless of when it was built, its location, or the materials used to build the home, can expose its residents to radon. As a result, radon testing may play an important role in the real-estate transaction process. If you would like to schedule a radon test for your home, please contact us today!

The EPA’s Radon Website www.epa.gov/radon is a great resource for detailed information, resources and the answers to frequently asked questions.


Our experienced team of inspectors proudly serves the following areas:

Chester County, PA

  • West Chester
  • Exton
  • Malvern
  • Downingtown
  • Kennett Square
  • Oxford

Delaware County, PA

  • Newtown Square
  • Media
  • Haverford
  • Radnor
  • Aston
  • Concordville

Montgomery County, PA

  • Limerick
  • Pottstown
  • Merion
  • Norristown
  • Abington
  • Horsham

New Castle County, DE

  • Wilmington
  • Hockessin
  • Newark
  • Bear
  • Middletown
  • Smyrna

Also serving portions of the following counties: Lancaster (PA), Berks (PA), Bucks (PA) and Kent (DE).

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