How often should I test for radon?

radon, mitigation

In conversations that I have with clients, I find that there is some surprise when I advise them that they should consider testing again in the future, regardless of whether the property fails the radon guideline or not.   

Why do we need to retest our property again for radon if the property was below the EPA action level of 4.0 pCi/L?   And if this is the case, when do we need to do the retest? First, we need to recognize that there is no “safe” level of radon.  The picocurie levels of radon gas are constantly fluctuating and can easily exceed 4.0 pCi/L if the conditions are right. Short-term testing only gives us a snapshot view of what the levels were during the test period (a minimum period of 48 hours is allowed for real estate transactions).  Usually the longer the test period goes, the more accurate the results.

We recommend doing radon testing during the following times:

Change of seasons

The change of seasons can drastically change radon levels.  The ground can harden during the winter season and can elevate the radon levels inside a home.  Remember that radon gas is naturally occurring and comes from the ground underneath buildings. The winter can typically have higher radon levels, but heat and humidity can also have an effect, so it is important to test in alternating seasons to get a better understanding of what the levels can be throughout the year.  

When you purchase or sell a home

This is becoming more and more of an accepted practice, and for some, it’s ranked right up there with the building inspection.  The EPA reports that any type of house could be susceptible to radon 1.  New houses can be airtight and trap radon gas.  Older houses can have several cracks in the foundation and allow radon gas to enter. Homes can have elevated levels even if there is no basement or crawl space.  Because radon is odorless, the only way to tell for certain is to have a test. Performing this test can provide peace of mind in making one of the largest purchases in our life.

In many cases, a buyer may want to see if a test was performed within the last two years.  If not, we recommend testing anyway. 

Radon level increases when you do remodeling

I had a client inform me that he didn’t think that the testing would be a big deal because he was going to perform a gut rehab of the property.  That would stop the radon gas anyway, right? Wrong! Doing substantive changes to a building can have a great impact on increasing levels because it can make the property more airtight.  Thinking of remodeling the basement? Replacing the windows? Replacing the roof? Seriously consider testing both before and after the remodeling. If you find the problem before remodeling, you will not have to go through the added expense of tearing out the walls and floors to install a new mitigation system.

When living arrangements change

If your place is like mine, you may find that your basement is primarily used for storage.  But with the advent of children, we have started spending more time in the basement where the kids spend time playing or watching TV.  As children get older or when parents move in, people may spend more time in the basement as a new living arrangement. When this happens, we would advise performing testing again to ensure that the new bedrooms/living areas are safe.

It doesn’t matter if you previously had a lower level.  In fact, the EPA encourages testing lower levels again even if an earlier test was below the 4.0 pCi/L if you are going to have anyone spend extensive time in this area2 

After a mitigation system has been installed.  

If you had a mitigation system installed, does that mean that you no longer have to worry about retesting?  Again, our answer would be “NO!”. Fans can fail or they may be running at too low a rate enough to lower the levels below 4.0 pCi/L.  What good is a mitigation system when the average level is 4.5 pCi/L? Testing is the only way to ensure that you are at an acceptable level after a mitigation.  

Commercial properties

When many people consider the effect of radon in their lives, they primarily consider their homes.  But what about their places of work? The dangers are still there and just as dangerous. Consider testing the workplace to ensure that radon gas is at an acceptable level.  

In fact, laws in many states require that daycares and nursing homes are tested on a regular basis.  In Illinois, the IEMA requires that radon testing occur at least once every three years3. 

How often should I test?

Although there are guidelines for daycares, there are no set guidelines for residential properties.  I personally believe that the above guideline of every two to three years in alternating seasons is a good one if your initial test was below 4.0 pCi/L.  But I would also suggest that it would be a good idea to do radon testing when any of the above-mentioned life changes occur. In radon testing, there is no such thing as “one and done”.

If you want more information or testing on testing for radon, please feel free to check out our website.

  1. https://www.epa.gov/sites/production/files/2015-05/documents/hmbuygud.pdf
  2. https://iaq.zendesk.com/hc/en-us/articles/212104437-How-often-should-I-test-retest-my-home-for-radon-
  3. http://dph.illinois.gov/topics-services/environmental-health-protection/toxicology/radon-testing
Scott Wieringa

Scott Wieringa

Scott Wieringa is a Senior Project Manager that performs indoor air quality assessments with a specialty in radon and odors. Mr. Wieringa holds a Bachelors of Arts degree from Calvin College. He is an ACAC Council-Certified Indoor Environmentalist (CIE) and Illinois Licensed Radon Professional with residential and commercial building endorsements. Prior to working at Indoor Science, Scott was a residential real estate appraiser with over 23 years of experience inspecting properties in varying capacities. In his words… “I have a special interest in helping clients track down how their homes or businesses might be making them sick. In my spare time, I’m involved in song writing, sketching and spending time with my family.”

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