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What Is Water Hammer?

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It's not uncommon for metal pipes to make a loud banging sound when the water is shut off. Water hammer is technically called “hydraulic shock.” It’s what happens when water makes a sharp stop or change in direction very quickly. This momentum causes a shock wave that travels through the pipes, forcing them to move, shake and bang together. So what’s that loud hammer-like banging sound that you hear when you turn off your water intakes? Yep, it’s just the sound of shock waves when the water suddenly stops. While it isn’t as loud, you can also experience water hammer with plastic pipes.

How will water hammer affect my plumbing?

Annoyance is not the only negative result of water hammering. It can wear out your pipes, causing them to start leaking or even burst. Plumbing issues can get messy and expensive. Water hammer can also be a physical risk if it’s caused from high water pressure that may be too hot or too forceful for people washing their hands or taking a shower. So if you hear water hammer, don’t just ignore it.

How to fix water hammer by installing or cleaning out air chambers

Modern plumbing that is properly installed has air chambers that help cushion the blow when the shock wave hits. The air chambers are vertical pipes that regulate pressure and stop water from making waves in your supply pipes. Over time, these air chambers can fill up with too much water, making them no longer effective. You can fix water hammer by turning off the water supply lines and then opening the faucets and allowing them to drain completely. Once water drains from the chamber, it will fill back up with air and reset the cushion. Depending on where your air chambers are located, you may have to drain the main supply lines to enable the air chambers to fill with air again.

Air chambers should always be a little larger than the main water supply line to help prevent clogging. However, on rare occasions the air chambers do get clogged with debris like scale, minerals, or residue from chemicals that have built up over time. This prevents the chambers from draining properly. If this happens, the chambers need to be cleaned by removing the caps and scouring them. While most plumbing systems have these built in, that’s not always the case, especially if you have an older home with outdated plumbing. If you need to get air chambers installed or cleaned, call a professional plumber.

Strange noises coming from your plumbing system are not always easy to identify or fix. Our plumbers can locate the source of the noise whether it’s non-existent air chambers, clogged air chambers, or high water pressure causing the problem. If you have problems with water hammer noise, don’t risk major plumbing damage and/or flooding. Contact our pros at A#1 Air Plumbing today.


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