history: I moved into a new house and in the middle of the night heard this horrible screeching sound from the basement. It was so scary! Turns out it was just the sump pump kicking in. I moved into this new house and was woken up with this horrible screeching noise in the middle of the night. Terrifying! What was it?
current: It turned out to be the sump pump, I guess it was old. But yes, it scared the daylights out of me!
next: Oh good. I bet!  I wouldn't have been able to go back to sleep after that!  Do you have to replace the pump?