I have noticed that there is a relationship with when the pump starts and stops. I can here the click of the relay. I'm not sure if it occurs when the pumping begins or ends though.
The plumbing in the house goes:
line from pump -> check valve -> pressure tank -> house.
Is this just a problem with the check valve? The tank holds pressure fine, but maybe 10 years has cought up with something?
Just to clarify, I have in in-well pump.
I've also read that similar noises may occur due to a leaky flap valve in my toilet (whic his lekaing slightly).
I can not isolate where the noise is coming from.
The noise starts quiet, gets loud then quiets down again. Maybe a 5 second duration.