That sudden (and alarming) bang or knock you hear through the walls when a tap shuts off isn’t your imagination, and it isn’t your pipes falling apart either – at least not yet. It’s called water hammer, and it’s one of those plumbing noises that can go from mildly annoying to extremely worrying if it happens often enough. How to stop water hammer? Let’s take a deep dive into that banging.
If you’re here to find out how to stop water hammer before it becomes a bigger and more expensive problem, you’re in the right place. Some of what follows you can check or try yourself, and some is worth getting a plumber to install properly – but either way it helps to understand what’s actually going on first.
What’s actually causing that noise?
Water hammer happens when water flowing through your pipes gets stopped suddenly – usually because a tap or valve closes quickly. All that moving water has nowhere to go in an instant, so it slams into the closed valve and sends a shockwave back through the pipework, which is where that knocking sound comes from. It’s a lot more common than people realise, and while an occasional bang isn’t usually a big deal, frequent or loud water hammer can seriously stress your pipes and fittings over time.
Simple ways to fix it yourself
A few of these you can genuinely check or adjust yourself, while others are simple, inexpensive jobs best left to a licensed plumber to install properly. Let’s dive into how to stop a water hammer before it knocks your pipes to bits:
1. Check your water pressure
High water pressure is one of the most common causes of water hammer, and it’s also one of the easiest things to check. If your home’s pressure is running higher than it should be, that extra force makes the shockwave from a closing valve much stronger.
A simple pressure gauge from the hardware store, attached to an outdoor tap, will tell you where you’re sitting. Most homes are comfortable somewhere between 350 and 500 kilopascals, and anything noticeably higher is worth addressing.
2. Install a pressure limiting valve
If your pressure test comes back high, a pressure limiting valve fitted to your main water line is often the fix. It regulates the pressure coming into your home, which reduces the force behind every water hammer event.
It’s a relatively simple, one-time fix that solves the root cause rather than just masking the symptom.
3. Secure loose pipes
Sometimes the banging isn’t really water hammer at all in the strict sense, it’s just a pipe that’s come loose from its bracket and is knocking against a wall stud or joist every time water moves through it.
So, take a walk through accessible areas, like:
- Under sinks
- In the roof space
- Under the house.
Look for any opportunities to do some tightening or adding pipe clamps where things feel loose – it can make a surprising difference on its own.
4. Add air chambers or water hammer arrestors
Older homes were often built with air chambers – small vertical sections of pipe with trapped air. They were designed specifically to cushion the shock when a valve closes. Over time, that trapped air can dissolve into the water, and the chambers stop doing their job.
If that’s the case, a licensed plumber can install modern water hammer arrestors, which do the same job more reliably and don’t need topping up over time.
5. Turn taps & valves more slowly
This one’s free and couldn’t be easier! It’s also worth trying immediately if you’ve noticed the banging happens right after you or someone in the house shuts off a tap quickly. Simply getting into the habit of closing taps a little more gently reduces the abruptness of the water flow stopping, which in turn reduces the force of the shockwave.
Sure, it won’t fix an underlying pressure issue, but it can noticeably reduce how often you hear it and the damage it does.
6. Check tap washers & fittings
How to stop water hammer in taps? It might just be very easy in this case. Check the tap washers and internal fittings, since worn components can make the shut-off action faster and harsher than it should be.
7. Investigate the washing machine
If you’ve made the connection between water hammer and your washing machine, you’re not imagining it. Trying to work out how to stop water hammer from a washing machine could lead you to the machine’s own solenoid valves, which snap shut extremely quickly at the end of each fill cycle. That makes them one of the most common single sources of the noise in an entire house.
Installing a water hammer arrestor directly on the washing machine’s supply lines is usually the most effective fix, since it absorbs the shock right at the source rather than relying on the rest of your plumbing to handle it.
When it’s time to call a plumber
Hopefully, you’ve now discovered how to stop water hammer in a house and resolved it at your place. But if the noise is still there, or it’s particularly loud, sudden and new, it’s worth getting a professional opinion rather than continuing to guess.
A plumber diagnosing how to stop hammer noise in water pipes might:
- Test your static water pressure properly
- Use listening equipment to trace exactly where the shockwave is originating from
- Recommend either a pressure limiting valve, properly installed arrestors at key fixtures, or in older homes, a look at whether ageing pipework itself needs attention.
Getting this diagnosed properly matters – because persistent, ignored water hammer can loosen joints and shorten the life of your pipes and fittings over time, turning a noisy nuisance into a genuine and hefty repair bill.
Still hearing the bang?
If you’ve tried to understand how to stop water hammer in pipes with our blog and you’re still stuck, get it looked at properly rather than living with it. Our licensed plumbers right here at Static Plumbing can diagnose exactly what’s causing your water pipe hammer and fix it properly the first time.
Call our friendly team or book online today.
