04-24-2020, 05:02 AM
We had the same problem and the culprit was toilet flapper. We didn't notice it during the day because the suspect toilet was getting flushed regularly during the day and set off the pump when we would expect it and didn't drain down enough in between normal for the mystery pump run. But it was a toilet that rarely got used at night so that is when it drained enough water to cause the pump to run.
Because it wasn't a flush the toilet would almost be done filling by the time the pump started so we never "caught" the toilet running when the pump was.
Try turning the water supply off to the toilets at night and check them in the morning. The one with the empty tank is the culprit.
Because it wasn't a flush the toilet would almost be done filling by the time the pump started so we never "caught" the toilet running when the pump was.
Try turning the water supply off to the toilets at night and check them in the morning. The one with the empty tank is the culprit.