If you’ve ever wondered what causes hammering in water pipes, you’ve no doubt already heard the problem! That loud, sudden banging that makes you jump – and wince about the damage it may be causing behind the scenes. Water hammer happens when you turn off a tap or when an appliance like a dishwasher or washing machine stops drawing water – and the noise itself is bad enough.
But, as you suspect, the real concern is the damage it really can cause to your plumbing system if left unaddressed. At Sunshine Coast Plumbing and Hot Water, we regularly attend Sunshine Coast homes where water hammer has been ignored until it’s caused:
- Leaking joints
- Split pipes
- Even damage to water-using appliances.
In this guide, we’ll explain why water hammer happens, what it can do to your plumbing, and how to prevent costly repairs. So let’s get straight into it:
What is water hammer?
It’s the shockwave that travels through your plumbing when moving water is forced to stop or change direction very suddenly. It’s not just a random or ‘normal’ quirk of old houses and plumbing systems – it’s a physical reaction inside your pipes. When water is flowing, it has mass and momentum – and if a valve closes quickly, all that moving water hits the closed valve like a hammer hitting a wall.
That shockwave can:
- Make a loud water hammer noise (bang, thud, or clunk) that echoes through the pipes.
- Send vibration through your plumbing system.
- Loosen pipe fittings over time.
What causes water hammering in pipes?
Several situations can cause water hammer to develop in a home or commercial plumbing system:
Fast-closing valves
Modern mixer taps, solenoid valves in dishwashers, and washing machines often close instantly. That rapid shut-off doesn’t give water time to slow down gradually, so it slams into the valve.
High water pressure
Excessive pressure makes water hammer more forceful because the water is moving faster when the valve shuts. Sunshine Coast homes connected to mains supply can sometimes exceed recommended residential pressure if a regulator is missing or faulty.
Lack of cushioning
Older systems may have once had air chambers or arrestors to absorb shock. Over time, these can fill with water or fail, removing the cushioning effect.
Loose or poorly secured pipes
Pipes that aren’t clipped or strapped securely can move when the shockwave hits, amplifying the sound and stress.
Long straight pipe runs
Longer lengths of pipe give water more room to build momentum before stopping, which makes the hammer effect worse.
The risks of ignoring water hammer
While you might be tempted to live with the occasional bang in your pipes, there are solid reasons to fix the issue sooner rather than later.
Water hammer can lead to:
- Burst or damaged pipes, with repeated shock splitting copper pipes, cracking PVC joints, or loosening threaded connections.
- Leaks inside walls or under floors, caused by even a small leak from a loosened joint resulting in hidden water damage and mould growth.
- Damage to expensive appliances like your washing machines, dishwashers, and ice makers, all given a rough ride by repeated pressure spikes.
- Faster wearing of tap washers, cartridges, and valve seals.
How to stop water hammer
Just wondering how to stop water hammer ASAP? Well, the right solution depends on the cause:
1. Check & regulate water pressure
Have a licensed plumber test your water pressure. If it’s too high, installing or adjusting a pressure reducing valve can significantly reduce hammering.
2. Install water hammer arrestors
These are small devices fitted near quick-closing valves that absorb the shockwave before it travels through the pipes. They’re especially effective for appliances like washing machines and dishwashers.
3. Add or restore air chambers
In some older homes, vertical capped sections of pipe were used as shock absorbers. If they’ve filled with water, they can sometimes be drained and refilled with air to restore their function.
4. Secure loose pipes
Strapping and clipping pipes firmly to framing can reduce movement and noise. This is particularly important in accessible areas like under floors or in roof cavities.
5. Replace worn valves & fixtures
Valves that don’t close smoothly or are partially obstructed can make hammer worse. Replacing them with modern, quality fixtures can help.
Can you fix it yourself?
Some minor issues – like slightly loose pipe clips in a visible location – can be tightened by a homeowner. But most water hammer fixes require specialist tools, correct diagnosis, and compliance with plumbing regulations.
For example:
- Fitting an arrestor incorrectly can trap debris or create new leaks.
- Adjusting water pressure incorrectly can cause other plumbing problems.
- Accessing pipes in walls, floors, or ceilings can involve cutting building materials and resealing them.
That’s why it’s best to have a licensed plumber inspect the problem, identify the exact cause, and apply the right solution for your system.
Preventing water hammer in new installations
If you’re renovating or building, water hammer prevention can be built into the design:
- Fit arrestors at appliances with quick-closing valves from the start.
- Use flexible hoses or pipe runs with slight bends to absorb shock.
- Keep water pressure within the recommended range.
- Ensure all pipes are clipped securely during installation.
By thinking ahead, you can avoid both the noise and the long-term damage risk.
When to call Sunshine Coast Plumbing and Hot Water
You should call us promptly if:
- The banging is getting louder or more frequent.
- You notice any signs of leaks – damp patches, mould, or musty smells.
- You’ve just installed a new appliance and the problem has started.
- You can feel pipes moving or rattling when taps are turned off.
We’ll carry out a thorough inspection, check your pressure, look for loose fittings, and recommend targeted solutions to protect your plumbing.
Need help with water hammer in Sunshine Coast?
Water hammer is more than just a noisy inconvenience – it’s a warning sign that your plumbing is under stress. Understanding what causes water hammering in pipes and acting quickly to fix it will save you from expensive repairs and keep your water system running smoothly.
Reach out to Sunshine Coast Plumbing and Hot Water today for fast, professional service anywhere in the city and beyond. From Buderim to Buddina, Caloundra to Cooroy – we’ll find the cause, fix the problem, and protect your plumbing from future damage. Give us a shout!
