Should I Test for Radon in My Crawl Space?

When testing for radon, should I test in the crawl space, living space or both? At what levels is radon considered bad? We hear these questions constantly. Because of the confusion surrounding radon and crawl spaces I decided to reach out to a radon professional.

I wanted someone who studies radon and teaches others how to address it. In my search I met Bruce Snead of Kansas State University. He was kind enough to be a guest on our YouTube Channel. I have placed the full interview below.

Is Testing the Crawl Space for Radon Recommended?

I asked Bruce this question. I was shocked at his answer. He said that he always told people that testing in a crawl space was unnecessary until his trip to San Francisco, CA. While there, he saw an advertisement listing a crawl space for rent. Since seeing that, this is what he says:

“I used to say you never test the crawl space for radon. Now I say, If the owner doesn’t live in the crawl space, you don’t test in the crawl space. I changed my answer after seeing a crawl space for rent in San Francisco.”

If you are concerned about radon, you can perform a DIY Radon Test Kit for home (affiliate link). They are simple to use and accurate plus shipping and lab fees are included.

What is the Best Radon Level?

Many understand that having a radon level under 4 pCi/L (picocuries per liter) is recommended. Under 2 pCi/L is optimal but in order to pass a radon test, under 4 is the standard most follow. Outside radon levels average around 0.4 pCi/L. So, that would typically be the best inside level one could expect to achieve. That being said, the lower the radon level in the home the better. Also, keep in mind radon levels inside your home can fluctuate. Fluctuations can occur due to: