You turn on the kitchen tap and it screeches like a kettle. Or the basin whistles every time someone runs a hand under it. Maybe it’s a low hum you only notice at night. A noisy tap is one of those faults that gets under your skin fast, and the good news is that most of them trace back to a handful of common causes you can narrow down in a few minutes.
TL;DR
- A squealing or whistling tap is nearly always a worn washer or a clogged aerator. Both are cheap and common.
- A banging or hammering sound when you shut the tap off is usually water hammer, which is a pressure issue, not a tap issue.
- Start by listening: note whether it happens on hot, cold, or both, and whether the noise comes from the tap itself or the pipes under the sink.
- Cleaning the aerator and checking the shut-off valve are safe DIY jobs. Pulling a tap apart or touching mains pressure is where most people should stop and call a licensed plumber.
First, listen to the noise. It tells you almost everything
Different noises point to different causes, so a bit of listening saves you guessing (and buying the wrong parts). The type of noise your tap is making can often help identify the likely cause.
Run through these quick checks before you touch a spanner:
- Hot, cold, or both? Does the noise occur when you turn on both hot and cold water, or just one side? This helps narrow down the problem. A noise on one side usually points to that tap or valve; noise on both often points to pressure.
- Tap or pipes? Listen carefully to see whether the noise is coming from the tap itself or from the pipework underneath the sink.
- When does it happen? A noise while water runs is different from a bang the moment you shut it off. The bang is water hammer, which is a separate problem covered below.
Squealing or whistling: usually a worn washer
This is the most common cause of a noisy tap, especially in older St George homes with traditional two-handle taps. As washers or valve components wear, they can begin to vibrate as water passes through them, leading to a squealing, screeching or whistling sound.
The mechanism is simple. As water is forced past a worn or perished washer, the rubber flutters against the seat and sets up a high-pitched vibration. On a mixer tap the same job is done by a ceramic cartridge, which can also wear or fill with grit over time.
Replacing a washer or cartridge is a genuine fix, but it means shutting off the water, dismantling the tap, and reassembling it correctly without over-tightening or cross-threading anything. Visible fittings can be checked carefully, but avoid overtightening components as this can damage the tap or surrounding fittings. If you’re not confident taking a tap apart, this is a fast, low-cost job for a plumber who carries the parts.
Whistling only when water runs: check the aerator
Before you pull anything apart, check the aerator. That’s the little screen on the very tip of the spout, and it’s the easiest fix on this list. A clogged aerator can cause whistling or squealing noises. In Sydney’s water, mineral deposits and grit slowly build up in the mesh and restrict the flow, which sets off the whistle.
To clean it:
- Unscrew the aerator from the faucet tip and rinse it thoroughly under running water to remove any debris.
- Soak the aerator in vinegar for a few hours if mineral deposits are present.
- Give it a gentle scrub with a soft brush, then screw it back on and test.
If the whistle is gone, you’re done. If it comes straight back, the noise is coming from inside the tap or the valve, and it’s washer or cartridge territory.
Half-open valve: the sneaky cause people miss
Under most sinks there’s an isolation valve for each tap. If one has been knocked or left partly closed, the water squeezes through a smaller gap and vibrates on the way past. All that water has to pass through a tiny opening, and as it does, it leaves the washer the chance to vibrate. Shut-off valves should always be left fully open to prevent this issue.
So before you assume the worst, check the under-sink valves are turned fully open. It’s a thirty-second check that occasionally saves a whole repair.
Banging when you turn the tap off: that’s water hammer
A bang or knock the instant you shut a tap is a different beast entirely, and it’s not really the tap’s fault. If you turn off a tap and hear a loud banging noise from your pipes, you’re experiencing water hammer, a common issue caused by sudden pressure changes. Water flows through your pipes under pressure, and when you turn off a tap quickly, the water has nowhere to go, so the momentum creates a shockwave inside the pipes.
A quick short-term reduction is to close taps a little more slowly, especially quarter-turn ones. But a persistent bang usually means loose pipes that need re-securing, or a system that needs a properly fitted water hammer arrestor. Both jobs mean getting behind walls or into the pipework, so they’re best left to a plumber rather than a DIY guess.
If your whole house rattles, hums, or bangs rather than just one tap, the cause is often system-wide. Our guide on why your plumbing makes noise walks through pipe-related sounds in more detail.
Humming or a low vibration: often high pressure
A steady hum while water runs frequently points to pressure that’s too high for the fittings. High water pressure can cause pipes to vibrate, resulting in noises from humming to banging, and it’s particularly common in older plumbing systems or areas with high municipal pressure.
Homes in the St George area can sit on higher-pressure mains, and that pressure can slowly wear washers and stress fittings on top of making noise. If you suspect pressure is the issue, don’t start adjusting a pressure-reducing valve blind. Getting the pressure measured and set correctly is regulated work in NSW and worth having a licensed plumber handle so it’s both safe and compliant.
What’s safe to try yourself, and what to leave alone
A few checks are genuinely fine for a confident homeowner:
- Cleaning the aerator.
- Confirming the under-sink isolation valves are fully open.
- Working out which side (hot, cold, or both) makes the noise so you can describe it clearly.
Leave these to a licensed plumber:
- Pulling the tap apart to replace washers or cartridges if you’re unsure, since it’s easy to damage the seat or cross-thread the reassembly.
- Anything involving mains water pressure or a pressure-reducing valve.
- Securing loose pipes inside walls or fitting a water hammer arrestor.
- A hot tap noise you suspect is coming from the hot water unit rather than the tap. That needs proper diagnosis, not guesswork near a heated system.
As a general rule, if the tap is old, leaking or repeatedly causing problems, it may be more practical to replace the tap or ask a qualified plumber to investigate rather than chase one fix after another.
A quick noise-to-cause guide
- Squeal or whistle while running: worn washer or cartridge, or a clogged aerator.
- Whistle that stops after cleaning the aerator: it was the aerator.
- Bang or knock when you shut the tap off: water hammer.
- Steady hum or vibration: often high water pressure.
- Noise on both hot and cold at every tap: likely a pressure or system-wide issue, not one tap.
When it’s time to call a plumber
If you’ve cleaned the aerator and checked the valves and the noise is still there, the tap likely needs a washer, cartridge or a proper look at the pressure. That’s routine work. Jasco keeps common washers, O-rings, cartridges and ceramic disc kits on the van, so most tap repairs are sorted in a single visit without a second trip. You can see how we handle it on our tap repair service page.
Next step: try the aerator clean and the valve check first. If the tap’s still whining after that, book a plumber to replace the worn parts before a squealing washer turns into a dripping one.