If you hear a loud bang, thud or vibration in your pipes when you turn a tap off or a valve closes, that's almost certainly water hammer. It's one of the most common plumbing complaints we come across — and while it can sound alarming, it's usually fixable.
What Is Water Hammer?
Water hammer is caused by the sudden stopping of water flow in a pipe. When you turn a tap off quickly, the water that was flowing has momentum — and when it stops abruptly, that energy has to go somewhere. It travels back along the pipe as a pressure wave, creating that characteristic bang or series of bangs.
Modern taps with ceramic disc cartridges are particularly prone to this, because they close much more quickly than older tap designs.
Is It Harmful?
In the short term, water hammer is more annoying than dangerous. But if it's left unchecked over a long period, the repeated pressure shocks can cause real damage:
- Loosening of pipe joints and fittings
- Damage to washing machine and dishwasher valves
- Wear on boiler components
- In extreme cases, burst pipes
It's worth getting it sorted properly rather than just putting up with the noise.
What Are the Common Causes?
Beyond fast-closing taps, water hammer can also be caused by:
- High water pressure — if your incoming mains pressure is very high, any sudden valve closure will produce a larger pressure spike
- Poorly secured pipes — pipes that aren't properly clipped can vibrate and bang against joists or walls
- Faulty or worn pressure reducing valves
- Air in the system — sometimes what sounds like water hammer is actually air-related noise
How Is It Fixed?
The right fix depends on the cause. We'll diagnose what's actually happening before recommending anything. Common solutions include:
- Fitting a water hammer arrestor on the affected line
- Adjusting or replacing the pressure reducing valve
- Re-securing loose pipework
- Fitting a different tap cartridge that closes more gradually
If you're hearing banging pipes and aren't sure what's causing it, give us a call. We can usually diagnose the issue on the first visit and carry out a repair the same day.