No radon next door? That doesn’t mean you’re in the clear.

December 23, 2019

Current radon level map from the CDC's website.

One the most ear grabbing topics for my clients is extreme radon levels. I’ve heard stories from all around the country, but Pennsylvania has some of the highest recorded levels in the world, ranging from 2000 pCi/L to the highest recorded in Pennsylvania: 6176 pCi/L — IN A RESIDENTIAL HOME! For comparison, the highest I’ve ever mitigated here in Minnesota is 65pCi/L (we got it down to 0.3!), and the highest I’ve heard of in Minnesota is 750pCi/L. Now, I’m glad we don’t see such high levels in Minnesota, but according to the EPA, no level is safe. They recommend installing a system in the 2-4 pCi/L range, and most buyers won’t go through with a sale if the house tests above 4.0 pCi/L.

So what can you even do if your house tests in the thousands? Well, Bill Brodhead had the “pleasure” (ha!) of working on the record-breaking 6,176 pCi/L house. He first installed a passive system, meaning a radon system without the fan, and it brought the levels down to somewhere in the 2,000s. A good start, and it goes to show that passive systems (when installed correctly) can really make a difference. When he added the fan, it reduced the levels from 2,000 down to around 50pCi/L, but nothing else seemed to make a difference. He had just installed the Cadillac of radon systems, creating negative pressure everywhere under and around the foundation, but the levels wouldn’t budge.

That’s when he decided to test the ambient outside air. He put a radon detector in the mailbox outside, and at night, the still outside air was averaging 50pCi/L. When Bill was presenting this at the New Orleans symposium, I was shocked to see the person who I consider “The Radon Guru” scratching his head, and turn to the crowd for suggestions. After his talk I caught up with him and said, “maybe a fresh air intake from above the house?” He'd already tried that, with a fresh air intake 36 feet in the air, pumping fresh clean air in the basement. That didn’t even work.

The interesting thing is, in a different new development in Pennsylvania were homes throughout the neighborhood had levels in the 2000 pCi/L range, right next door the neighboring home would test at 200 pCi/L, which is still extremely high, but radon levels were 10x less?! Sometimes when we’re working on homes here in the Twin Cities, neighbors will come over to see what we’re up to, and will ask us to test their home. One house we recently worked on tested around 6.0 pCi/L, and right next door the neighbors home was at 0.7 pCi/L, almost clean outdoor air.

The only way you can know if you have a radon problem is testing, your neighbors levels are no indication of your homes radon levels. It’s very easy and affordable to test your home, check out to get a simple, DIY test. Or give us a call, and we’ll provide professional testing and mitigation services.