I need some plumbing advice. I have a problem that I am trying to figure out. I have a gas water heater that's never been drained or service in the 11 years that I have owned it. Last month I tried to drain it but it was clogged with what I think is hard water and sediment. I also have galvanized pipes that were installed in 1964. This my problem I am starting to hear a bellowing noise from either the pipes or the water heater. I am not sure from where of the two its coming from/ Would the water heater cause that noise or could that be from the pipes being old? I seen inside some pipes and they also have sediment in them too.