How to stop pipes making banging sounds?

[AussiePossum]

My pipes sometimes make a banging/shaking sound, e.g., when I use my washing machine; I understand this is being caused by "water hammer." I'm concerned about the potential damage that this could be doing to my pipes. Please could you advise if installing a pressure-limiting valve at the main water meter would help? Or maybe the installation of a water hammer arrestor? Thanking you.

[MitchellMc]

Welcome to the Bunnings Workshop community @AussiePossum. It's sensational to have you join us, and many thanks for your question about water hammer.

What you're hearing is very likely water hammer, which is a pressure surge that happens when water flow is suddenly forced to stop or change direction, like when a washing machine valve closes quickly. That sudden jolt causes the pipes to bang or shudder, and over time, it can stress joints and fittings.

A pressure-limiting valve at the main water meter can definitely help if your overall water pressure is high, and it often is in newer estates or areas close to mains infrastructure. Lowering the pressure can reduce the severity of the hammer, but it doesn’t directly fix the hammering itself.

For that, water hammer arrestors are the most effective solution. These are small devices that get installed near the source of the noise — usually near appliances like washing machines, dishwashers, or taps that close quickly. Inside the arrestor is a chamber with either air or a piston that absorbs the shock when the water flow stops suddenly, acting a bit like a cushion. That takes the stress off your pipes and stops the banging sound.

In many cases, combining both approaches works best: install a pressure-limiting valve at the meter if your pressure is up above 500–600kPa, and then add arrestors close to the noisy fixtures. You can get arrestors that screw directly into the washing machine hose tap, so installation can be pretty straightforward for a plumber.

Please let me know if you have any questions.

Mitchell
 

[AussiePossum]

Hi Mitchell, thank-you so much for your help, we really appreciate you taking the time to explain about the pressure-limiting valves and water-hammer arrestors. We will explain the issue to our plumber, and if he doesn't already have those items in his van, we will call into our nearest Bunnings to get one of each. 😊