Recently I started noticing a quite annoying sound when any 2nd story toilets flush or kitchen faucet on the main floor is closed. There are three toilets on the second floor of my 2-story house. Each of these three toilets operate fine. After each of the toilets is flushed, the water tank fills without any unusual noises. Just after the tank is filled and the valve is shutoff, there is a short burst of sound. I guess the best way to describe is that it sounds like a short burst of foghorn based on how I have read other people describe it. The same sound occurs when kitchen sink faucet is shut off and during wash cycle in clothes washer. Just now as I am writing this question, I just heard the same sound when 2nd story bathroom faucet is closed. The difference between the various posts I have read on the web about this type of sound and the problem I am hearing is that the sound that I am hearing is just a short burst of sound as a valve (i.e. toilet valve, kitchen faucet, or washer water intake valve) is closed.

I tried one suggestion I found on the web to try to isolate the sound. I shut-off water intake on toilet water intake valves, kitchen faucet,etc. to try to isolate the problem. No luck.

Any suggestions would be greatly appreciated.