I have just moved into a new house and there is an annoying droning sound (like a fog horn in the distance) that comes from the laundry area. I can feel a slight vibration through the cold tap in the laundry basin.
Sometimes it makes the sound for no reason, other times it occurs after you turn any tap off (hot or cold). It stops whenever you turn a tap on but starts again when you turn it off. It can last for several minutes. Any ideas what this is?