Why Radon Testing Should be done in Multiple Locations

May 31, 2019

The real estate market is moving along in the Chicagoland area and it is the prime season for radon testing.  We have covered in prior blogs the importance of knowing the radon levels. We have also reviewed why it is so important to test.  But occasionally, I get questions regarding why I test in multiple locations in the property (typically in four areas). Don’t most radon companies typically leave one device for 48 hours and call it a day?  What’s the point in testing a number of locations?

Multiple foundations – Multiple pathways for radon

One reason for testing multiple locations would be if there were multiple foundations. Testing should be performed in each lowest area suitable for occupancy regardless of what devices you use https://www2.illinois.gov/iema/NRS/Radon/documents/radontestguidelineforrealestate.pdf .  For instance, if you have a partial basement and a crawlspace, the measurement devices should be placed in the basement and in the living area above the crawl. Or maybe the property has a basement but the addition is on a slab foundation. In that case, the basement and addition need to be tested separately.

Results can vary from place to place

Second, radon will not be evenly distributed in the property. Testing in multiple locations may reveal a radon problem in a single area where the other devices show acceptable levels.  I performed a radon test last year where one device exceeded the 4.0 Picocurie level in a large wine cellar but radon levels were much lower throughout the rest of the basement. The client reported that he liked to spend his free time in this cellar and smoke.  As an aside, when smoking is combined with elevated levels of radon, it significantly increases your chances of getting lung cancer https://www.epa.gov/radon/health-risk-radon#riskcharts . In his case, the radon problem would never have been discovered had we just performed a single test in the middle of the basement.  Testing multiple locations can catch these issues limited to one corner of the property.

Fixing the problem near the source

Another reason for performing multiple radon tests is to aid in the placement of a radon mitigation system.  Again, if there are elevated levels of radon found in just one section of the home, it greatly helps to know where the mitigation system should be placed to aid in more efficiently removing the gas.  

And finally, since it is well established that radon is the second leading cause of lung cancer https://www.epa.gov/radon/health-risk-radon , four tests are better than one!  Multiple testing can give a homeowner a greater sense of confidence that their home is safe from this dangerous gas.

Peace of mind

Whether purchasing a new home or just wanting the peace of mind knowing that your property is safe from elevated levels of radon, we generally recommend testing in a number of locations.  If a basement is very small, one location is probably acceptable. However, we would recommend testing in multiple locations if the home is particularly large, especially if it is older in age.  Cracks in the foundation of an older home can more easily allow radon gas to make its way into your living space. Since radon is an odorless, colorless gas, the only way to know for certain is to test.  Be sure to ask your radon professional if testing in multiple locations is a possible option.