Water flowing in pipes can cause all kinds of weird noises. The sound of water running through a pipe itself isn't too bad, but what about some of those other plumbing sounds—creaks or cracking, rattling, whistling, and the most annoying or scary of them all -- that loud banging noise. Let's look at what causes those sounds and how you can fix them to make your home a quieter place.
Creaks or a Cracking Sound
These are usually caused by the expansion and contraction of the water pipes themselves. As hot water runs through a pipe, it naturally heats the pipe itself, causing it to expand slightly. Once the water stops flowing, the pipe cools and the metal contracts, resulting in the creaking or cracking sound. The easiest way to fix this is to put some insulation around the pipe, or if the pipe is running through a tight fitting hole in the wood framing, cut a notch in the framing so the pipe can expand and then contract without that sound.
The cause and remedy for this noise is similar to the cracking sound. The rattling comes from the pressure of water running through a loosely attached pipe which causes it to vibrate slightly. When a loose pipe vibrates against something solid, like framing or the strapping designed to hold it, you hear the rattling sound. Stopping the pipe from vibrating will fix the rattle, so put some cushioning around the pipe or fasten the strapping more securely so the pipe won't vibrate.
This is usually caused by water flowing through a restricted section of the plumbing. The restriction can be sediment in the pipe or a defective washer or valve. If the whistling only occurs when a particular faucet is turned on, that's likely where the problem is, and replacing the washer or repairing the valve seat there should fix it. However, if the whistling sound occurs when any faucet is turned on, the problem is more likely in the main water supply valve itself. Adjusting the water pressure at the main water valve may dislodge the impediment, or the change in water pressure itself could get rid of the whistling sound. If that doesn't eliminate the problem, you may have to get the water valve replaced.
The loud banging sound when you shut off the water flow is actually called "water hammer" and is a fairly common complaint in older homes. The flow of water through the pipes contains energy, and when the flow is abruptly stopped, this energy causes the loud banging sound. Initially, a home's plumbing system was built with short pieces of pipe that filled with air and acted as air cushions to absorb the water's energy when the flow was stopped abruptly. However, over time the air has leaked out, meaning there is no air cushion left to absorb the water energy.
You can put that air cushion back into your plumbing system by turning off the main water supply and opening all the faucets in the house to drain the system. Next, turn the water supply back on and work your way up through the house, turning off the faucets as water flows through them. This should trap some air in the air chamber so it will once again provide the cushioning effect. If this doesn't work, you can buy a "water hammer arrester" that attaches directly to the water supply pipe where the water hammer originates.
If your plumbing is making any of these sounds, you should be listening because it's telling you it needs some maintenance. The sound is caused by something not working properly in your system and if you ignore it, over time, that small sound could lead to larger problems.
Murray Anderson is an experienced freelance writer with articles published in both the United States and Canada. He has written on a wide range of topics, but specializes in home maintenance and how to's.