When either upstairs shower is used, there is a tapping sound every few seconds (not in the shower itself, but you hear it in other rooms like it's behind a wall. Turn the shower off, you might hear it once or twice then no more. The water heater is in the basement. My first thought was a loose pipe, but there is no expansion tank on the water heater and it is a closed system, so now I'm thinking that's the likely culprit. Though I understand it may be a loose pipe or even a bad shower valve. The water pressure is pretty poor compared to my own home. I'm going to check the pressure with a gauge and add an expansion tank as it should have one anyway.
Have any of you folks ever experienced anything like this? What was the resolution? Thanks!