Why Is My Tap Making a Banging or Hammering Noise?

A banging or hammering noise when you turn a tap on or off can be surprisingly loud and more than a little alarming. It might sound like someone knocking inside the walls, or a sudden thud that happens the moment the water stops. Many homeowners first notice it at night when the house is quiet, or when using the washing machine or a mixer tap in the kitchen.

The good news is this kind of noise is common and usually linked to how water moves through your pipes, not an immediate plumbing disaster. In most cases, it is a sign of pressure changes or pipe movement rather than something about to burst. That said, it is still worth understanding what is causing it, because ongoing banging can place extra stress on your plumbing over time.

What Is Water Hammer?

Water hammer is a common plumbing issue that happens when flowing water is forced to stop or change direction suddenly inside your pipes. When this occurs, the momentum of the moving water creates a pressure surge that travels through the plumbing system. That surge is what causes the loud banging, knocking or hammering noise you hear.



It is most noticeable when a tap, mixer or appliance valve shuts off quickly. Instead of the water slowing down gradually, it slams to a stop, sending a shockwave through the pipes. The pipes can move or vibrate slightly in response, which is why the noise often seems to come from inside walls or ceilings.

When the Noise Is Most Noticeable

Banging or hammering taps tend to stand out at certain times, even if the underlying issue is present all day. The timing and situation often make the noise feel more dramatic than it actually is.

During quick tap shut-off, the noise is usually at its loudest. Turning a tap off sharply or flicking a mixer handle down can cause water to stop suddenly, triggering the pressure shock that leads to banging. This is why the sound often happens at the exact moment the tap is closed rather than while water is flowing.

When using appliances like washing machines or dishwashers, the noise can seem random or harder to trace. These appliances use internal valves that open and close very quickly during cycles. Each rapid shut-off can send pressure back through the pipes, causing knocking sounds even if no taps are being used at the time.

At night, the noise often feels more noticeable simply because the house is quieter. With less background sound, even a mild bang inside the walls can sound loud and unsettling. Reduced water use across the household can also change pressure behaviour, making plumbing noises more obvious during evening or early morning hours.

Is a Banging Tap Dangerous?

The short answer is usually no. A banging or hammering tap is rarely an immediate danger, and it does not mean a pipe is about to burst. In many homes, the noise has been happening for years without any sudden failure. However, that does not mean it should be ignored completely.

If the underlying cause is left untreated, repeated pressure shocks can place ongoing stress on your plumbing system. Over time, this stress can loosen pipe joints, wear down tap components and weaken fittings. What starts as an occasional noise can eventually lead to leaks, dripping taps or reduced water control.

Repeated pressure surges also cause pipes to move and vibrate more than they should. This constant movement can rub against framing or other pipes, increasing wear and raising the risk of hidden damage inside walls or ceilings. Addressing the cause early helps protect the long-term reliability of your plumbing and reduces the chance of bigger problems developing later.

Simple Checks Homeowners Can Do

There are a few simple observations homeowners can make to better understand where the noise may be coming from, without pulling anything apart or attempting repairs.

One way to check if the noise is pressure-related is to notice when it happens. If the bang occurs mainly when taps are turned off quickly, or when appliances finish filling with water, pressure shock is a likely cause. A very sharp, sudden noise usually points to water stopping too fast rather than a slow mechanical fault.

Listening carefully can also help narrow down the source. Try turning taps on and off one at a time and note where the sound seems loudest. Even though the noise may echo through the house, it often originates near the fixture or appliance that triggered it. Pay attention to whether the sound feels like a single thud, repeated knocking or ongoing vibration, as this can hint at different causes.



It is important to understand that temporary fixes rarely solve the underlying issue. Turning taps off more gently or avoiding certain fixtures may reduce the noise, but it does not address pressure levels, pipe movement or worn components. Without proper assessment, the stress on the plumbing system remains and the problem can slowly worsen over time.

Why the Noise Can Come and Go

Banging or hammering noises are not always constant, which can make them confusing and easy to dismiss. In many cases, the sound appears and disappears depending on conditions inside and outside the home.

Changes in water usage play a big role. When multiple taps or appliances are used at the same time, water flow and pressure behave differently. The noise may show up during busy periods, then disappear when usage drops, even though the underlying cause has not changed.

Seasonal pressure fluctuations can also affect how noticeable the problem is. Water supply pressure can vary throughout the year due to demand, maintenance work or environmental factors. These subtle shifts can be enough to trigger or silence banging noises without any changes being made inside the home.

Even if the noise is intermittent, it still matters. Plumbing issues linked to pressure shock or pipe movement do not fix themselves. A problem that only happens occasionally can still cause gradual wear on pipes and fittings, making it worth paying attention to before it becomes more frequent or severe.

When a Professional Plumber Needs to Be Involved



While occasional noise can seem harmless, there are situations where a professional assessment is the safest next step. If the banging or hammering becomes louder, more frequent or starts happening across multiple taps and appliances, it usually indicates a system-wide issue rather than a single faulty fixture.

A plumber should also be involved if the noise is accompanied by other warning signs, such as visible leaks, vibrating pipes, fluctuating water pressure or taps that are difficult to control. These symptoms suggest the plumbing system is under ongoing stress and may be at risk of damage if left unchecked.

A plumber can also identify pressure problems, secure loose pipework and assess internal components properly, helping prevent long-term wear and unexpected failures. Best Plumbers Adelaide service Greater Adelaide, including Northern Suburbs, Port Adelaide, and Barossa Valley region.