Pounding noises from pipes usually indicate a problem with water flow or pressure. Two of the most common causes are water hammer and trapped air bubbles. A water hammer, also known as a hydraulic shock, occurs when moving fluid suddenly stops when a faucet or valve is turned off. Gurgling sounds usually come from drain pipes, which can be caused by blockages in the water pipes due to hair, grease, soap scum, or objects falling down the drain.
When the water is running and then suddenly shuts off, the flowing liquid has nowhere to go and hits the shut-off valve, resulting in a loud, dull sound known as a water hammer. This can damage the joints and connections of the water pipe. Copper pipes tend to expand as hot water passes and transfers some of its heat to them. Lowering the temperature of the water heater can help address this issue.
A whistle indicates that a water valve somewhere in the pipeline is partially closed. Buildup in pipes reduces space for water, which can cause squeaking when water tries to pass through pipes. Washers, toilet components, and the like can wear out or break, resulting in noisy pipes at the site where they are used. Water hammer is the loud knocking or “pipe rattling” sound heard when you turn on a faucet, run water, and quickly turn off the faucet.
Re-securing pipes can reduce rattling noise and prevent damage to water pipe joints. It could also be a damaged or blocked P-trap, emitting a foul odor and requiring the help of a professional plumber to repair it.