Noisy water pipes can be as irritating to live with as they are frustrating to diagnose. Yet taking the time to stop the problem at its source can head off expensive plumbing damage later. Different sounds indicate different underlying problems.
A single sharp bang, sometimes followed by a shuddering vibration, may occur when a suddenly closed valve forces flowing water to stop abruptly--for instance, when a dishwasher finishes its run cycle. To combat this "water hammer" effect, most modern plumbing includes air chambers or water hammer arresters. However, air chambers can become waterlogged and arresters can wear out over time.
Thumping or Rattling
Within the walls, pipes that are not well strapped down can move during use, thumping, rattling or even squeaking.
A series of rapid-fire percussive sounds suggests that a dishwasher or washing machine solenoid fill valve is worn out.
Low- or High-Pitched Tones
Humming, moaning, mooing, whistling and shrieking all can result from excessively high water pressure, which causes harmonic vibrations in the pipes. Water rushing past loose or worn-out washers---notably those in faucets and toilet valves---can also emit various tones.
Intermittent Running Water
A toilet with a leaking flush valve can produce a recurring intermittent sound of running water.