To diagnose noisy plumbing, it is important to determine first whether the unwanted sounds occur on the system’s inlet side-in other words, when water is turned on-or on the drain side. Noises on the inlet side have varied causes: excessive water pressure, worn valve and faucet parts, improperly connected pumps or other appliances, incorrectly placed pipe fasteners, and plumbing runs containing too many tight bends or other restrictions. Noises on the drain side usually stem from poor location or, as with some inlet side noise, a layout containing tight bends.
Hissing noise that occurs when a faucet is opened slightly generally signals excessive water pressure. Consult your local water company if you suspect this problem; it will be able to tell you the water pressure in your area and can install a pressurereducing valve on the incoming water supply pipe if necessary.
Thudding noise, often accompanied by shuddering pipes, when a faucet or appliance valve is turned off is a condition called water hammer. The noise and vibration are caused by the reverberating wave of pressure in the water, which suddenly has no place to go....