In article , Rod Hewitt
writes
Well good ol' neighbours. They have a problem with their water supply.
Several times a day it makes an awful noise - trying to describe it I
came up with foghorn - but a bit higher pitched.

This happens in our industrial unit at work. It happens (only sometimes)
when the hot water header tank is filling. It appears to be caused by a
long length of unsupported pipework resonating.

I think changing the ballcock valve in the hot water header tank to a
torbeck type thing (or maybe just a new ballcock valve) would fix it.
--
Tim Mitchell