What Causes Banging Pipes? Water Hammer and How to Fix It
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If your pipes bang or thump right after you turn off a tap, or when the washing machine finishes filling, you’re dealing with water hammer. It’s a common cause of banging and noisy pipes in Melbourne homes. It can sound alarming, but it’s usually fixable without major work.
What Is Water Hammer?
Water hammer happens when fast-moving water in a pipe is suddenly stopped, usually by a tap or valve closing quickly. That sudden stop sends a pressure shockwave back through the pipe, which knocks the pipe against the framing or its fittings. That knock is the banging you hear.
Common Causes of Water Hammer
Loose Pipe Fittings
If a pipe isn’t properly secured to the wall or frame, it can move slightly under pressure. Even a small pressure change will then make the banging louder.
Missing or Failed Water Hammer Arrestors
A water hammer arrestor is a small device made to absorb the shockwave. Many older homes never had them fitted. Newer homes often do, but an arrestor can wear out over time and need replacing.
High Water Pressure
The higher your household water pressure, the harder the shockwave hits when a valve closes suddenly. If your pressure is too high, you’ll hear water hammer more often and more loudly.
Fast-Closing Valves and Appliances
Modern washing machines, dishwashers and other appliances with solenoid valves shut off water much faster than a normal tap. That’s why banging pipes are often most noticeable right as a wash cycle ends.
Is Water Hammer Dangerous?
An occasional bang is more of a nuisance than a danger. If it happens regularly, though, the repeated pressure shocks can loosen joints, wear down valves and shorten the life of your pipes and appliances. It’s worth fixing.
How to Fix Water Hammer
The right fix depends on the cause. The most common ones are securing loose pipes, fitting or replacing water hammer arrestors near the fixtures that bang, and installing a pressure reducing valve if your water pressure is too high. A plumber can test your water pressure and check your pipework to work out which of these your home needs.
If the banging happens every time you turn off a tap or the washing machine finishes, get it looked at properly. When you search for a plumber near me, choose one who mentions water pressure or water hammer work specifically. They’ll bring a pressure gauge and know what they’re testing for, which makes them a better bet than a general call-out.
Plumb Construct diagnoses and fixes water hammer for homes and businesses across Melbourne, whether the job needs an arrestor, a pressure reducing valve or just a loose pipe secured.
Frequently Asked Questions
Why does my washing machine cause banging pipes?
Washing machines use solenoid valves that shut off the water almost instantly. When the machine finishes filling, the water in the pipe stops suddenly, and that’s one of the most common triggers for banging pipes at home.
Will a water hammer arrestor definitely fix the banging noise?
In most cases, yes, as long as the arrestor is the right size and is installed close to the fast-closing valve. If your pipes are also loose or your water pressure is very high, those problems need fixing too before the banging stops completely.
Can water hammer damage my pipes over time?
Yes. If it’s left for a long time, the repeated pressure shocks can loosen joints, put stress on fittings and shorten the life of your pipes and the appliances connected to them.
Is water hammer more common in older homes?
It can be, especially in homes without water hammer arrestors or where the pipes weren’t secured well when the house was built. It can still happen in a home of any age, though.
How do I know if my water pressure is too high?
A plumber can test your water pressure with a gauge in a few minutes. As a general guide, residential water pressure above 500kPa is considered high and increases the risk of water hammer and other issues.
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