We recently had a radon mitigation system installed in our sump pump pit. Our house was built in 2005 with a poured full basement. When the mitigation system was installed back in December, the sump pit was dry and really doesn’t run that much until spring.

Now with the spring thaw and rains, our sump pump runs a lot. A month ago, I noticed that the sump pump seemed to run continuously, even without any water to pump. It was almost as though the float was stuck in the down position. We replaced that sump. About 10 days ago, I noticed that I wasn’t hearing the pump run. The sump pit was full of swirling water. The new sump pump wasn’t working. So with a little bit of experimenting, turning power off to the radon mitigation system, the sump pump works.

I’ve called the installation company for the mitigation system and they say they have never heard of this issue. We just got back from vacation and now have 4 inches of water in the basement. What is it about that system in our sump pump pit causing our sump pumps to fail? The installation company is supposed to come out and fix this issue by going through the slab which scares me as that seems it can be a source for water to get in to the basement if not well sealed.

  • definately something wrong. but it's unclear what you actually did. probably more details needed unless someone can guess.
    – Jasen
    Commented Apr 17 at 2:37
  • 2
    Thing being, thousands if not millions of radon systems are installed with sump pumps - and huge suction for a radon system is maybe 6" of water, while sump pumps happily pump it up 120inches or more. Meaning the radon suction is irrelevant to the sump pump, normally. So something highly unusual is going on if "turning the radon system off makes the sump pump work." What that might be is unclear from the details so far, as there really are not many. What do the pressure monitors (manometers) on the radon system show for the basement suction?
    – Ecnerwal
    Commented Apr 17 at 2:45
  • What details can I add? When the sump pump isn’t working, both sides of manometer are equal level. Hubby said that when he turned the system off, he hit the sump pump and it started working. I can also add that the engineer’s report when the house was built stated “seasonally severe high water table”. I don’t know the manometer reading when he went to the basement and discovered the water when we got home. I do have two Radon eyes, one on basement level and one on first floor, and can see the spike in radon when the system/sump pump must have malfunctioned after we left.
    – KAD
    Commented Apr 17 at 3:45
  • "When the sump pump isn’t working, both sides of manometer are equal level." Well, that means the radon system isn't on, or isn't working, anyway, at that point, as there's no suction. So at least from a suction point of view, there would be no difference if it was on or off then. Are they sharing a power circuit? You could edit your question to add pictures, there might be something visibly peculiar about this setup.
    – Ecnerwal
    Commented Apr 17 at 11:03

1 Answer 1


From your comments: "Hubby said that when he turned the system off, he hit the sump pump and it started working."

Hitting the pump to fix it is a classic fix for a stuck rotor. This means you have a defective sump pump.

The radon system is unrelated to your sump pump problem. You're looking for a connection when this is simply a coincidence. You put in a replacement pump that failed early. It happens. Replace it and move on.

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