Noisy pipes aren’t just annoying. They’re often an early warning sign of a problem that’s putting real stress on your plumbing system, and in Melbourne, one specific cause shows up more than any other.
Water Hammer: The Most Common Cause
That loud bang you hear when a tap shuts off or the washing machine finishes filling is called “Water Hammer”. Moving water carries momentum, and when a valve closes suddenly, that momentum has nowhere to go. It slams into the pipe wall and sends a shockwave through your plumbing, which is exactly the noise you’re hearing.
In Australia, water pressure at any outlet is legally capped at 500 kPa under AS/NZS 3500.1, enforced by the Victorian Building Authority. Homes built before this rule was introduced, or properties on higher-pressure sections of the mains network, are far more likely to experience noticeable water hammering. We’ve covered exactly how this rule works and why it matters in our article on the 500kPa water pressure rule.
Other Common Causes of Noisy Pipes
Loose or Unclipped Pipework
Pipes that weren’t clipped securely during installation can vibrate or knock against timber framing or wall cavities every time water flows through them. This tends to produce a rattling or knocking sound rather than a single sharp bang, and it often gets worse over time as fixings loosen further.
Worn Tap Washers
A high-pitched whistling or screeching sound, particularly when a tap is partially open, is usually a sign of a worn washer inside the tap. As the washer degrades, it vibrates against the valve seat and creates that distinctive noise. It’s a simple fix, but it’s worth having leaking or noisy taps looked at before the washer fails completely and starts leaking as well.
Thermal Expansion
A ticking or creaking sound, especially from pipes near your hot water system, is often just pipes expanding and contracting as hot water moves through them. It’s usually harmless on its own, but persistent creaking can point to pipes rubbing against timber or brackets that need adjusting.
Trapped Air in the System
Gurgling or intermittent banging that doesn’t line up with any obvious tap use can be caused by air trapped in the pipework, often after work has been done on the water supply or following a mains interruption. This sometimes clears itself after running taps for a while, but persistent air pockets usually need a professional flush of the system.
Appliance Solenoid Valves
Washing machines and dishwashers use solenoid valves that snap shut almost instantly at the end of a fill cycle. If the banging only happens when one of these appliances finishes filling, the appliance connection itself is almost certainly the trigger, particularly in a home with borderline high pressure.
Pipes banging every time a tap shuts off? Call Ezy-Plumb and we’ll track down the cause.
Why You Shouldn’t Just Ignore the Noise
A single bang now and then might seem harmless, but repeated water hammer gradually loosens pipe joints, stresses solder connections and can crack older fittings over time. What starts as an annoying noise can eventually turn into a genuine leak or a burst pipe, often in a spot you can’t see until the damage is done.
This is particularly worth taking seriously in older Melbourne homes with copper pipework, where hidden damage from years of water hammer sometimes only shows up once a pipe finally gives way. If you’ve had persistent noise for a while, it’s worth having a water leak detection check to rule out any damage that’s already happened out of sight.
Practical Tips Before You Call a Plumber
- Note exactly when the noise happens; after a tap shuts, during appliance cycles, or seemingly at random
- Check whether the noise is a single bang, a rattle, a whistle or a persistent tick
- Test your water pressure with a simple gauge on an outside tap if you have one
- Check whether the noise started after any recent plumbing or appliance work
- Don’t ignore whistling taps; a worn washer is a simple fix that prevents a bigger leak later
Common Mistakes to Avoid
The biggest mistake is assuming banging pipes are just a quirky feature of an older house. In most cases there’s a specific, fixable cause, and the noise itself is an early warning sign rather than something to live with indefinitely.
Another mistake is installing a water hammer arrestor on a single appliance without addressing high pressure across the whole property, if that’s the actual root cause. It might quiet the immediate noise, but the rest of your plumbing is still under the same excess strain.
Not sure if it’s water pressure or something else? Call Ezy-Plumb for a proper diagnosis.
When to Call a Professional
Testing and adjusting water pressure and fitting a pressure limiting valve if needed, is licensed plumbing work in Victoria. If your home is on high mains pressure, was built before 2003, or you’ve noticed banging alongside leaking taps, running toilets or appliances failing earlier than expected, it’s worth getting your pressure properly tested rather than guessing.
Final Thoughts
Noisy pipes are almost always trying to tell you something. Most of the time it’s excess water pressure, occasionally it’s a loose fitting or a simple worn washer, but either way, it’s worth working out before the noise turns into a genuine leak or burst pipe.
If you’ve got a plumbing emergency right now, call Ezy-Plumb and get it sorted fast. Our team also handles emergency plumbing across Melbourne’s Bayside suburbs, day or night.
FAQs
Q: Why do my pipes bang when I turn off a tap?
Ans: This is usually a water hammer, caused by moving water suddenly stopping and sending a shockwave through the pipes, often linked to high water pressure.
Q: Is banging in the pipes dangerous?
Ans: It’s not an immediate danger, but repeated water hammer can loosen joints and fittings over time, increasing the risk of leaks or a burst pipe.
Q: What is the legal water pressure limit in Australia?
Ans: Under AS/NZS 3500.1, static water pressure at any outlet must not exceed 500 kPa. See Victorian Building Authority for the full requirements.
Q: Can I fix the water hammer myself?
Ans: Minor cases sometimes improve by draining the system to clear trapped air, but persistent water hammer linked to high pressure requires a licensed plumber to test pressure and fit a pressure limiting valve.
Q: Why does my toilet or washing machine make a banging noise specifically?
Ans: These fixtures use valves that shut off very quickly at the end of a cycle, which makes them common trigger points for water hammer, especially on higher-pressure systems.
Q: Is a burst pipe caused by a water hammer covered under a rental urgent repair?
Ans: Yes. A burst water service is classified as an urgent repair under Victorian tenancy law. See Consumer Affairs Victoria for the current rules.
Q: How much does it cost to fix noisy pipes?
Ans: Costs vary depending on the cause, from a simple washer replacement through to fitting a pressure limiting valve, so it’s best assessed on site by a licensed plumber.
