Why Your Tap Drips: Washer, O-Ring or Spindle Wear Explained
You know the sound, and you know the sight: a tap that keeps dripping even after you have turned it off as hard as you dare, or a damp patch that keeps reappearing under the handle. It is one of those small household annoyances that feels like it should be simple, and the good news is that it usually is simple to understand. A drip is almost always one small sealing component inside the tap that has worn out, not a broken tap, and where the water actually appears tells you which component it is. By the end of this article you will be able to describe your fault accurately, which is half the battle when it comes to getting it sorted properly.
A dripping tap almost always means a worn sealing part, not a broken tap. Water from the spout usually points to a perished washer or ceramic disc. Water seeping around the handle points to a failed O-ring or spindle seal. Where the water appears tells you which component has worn and needs attention.
What Actually Stops the Water Inside a Tap
The thing to understand first is that a tap does not squeeze the pipe shut to stop the water. Instead, it presses a seal firmly against a fixed surface called a seat, and as long as that seal and seat meet cleanly, no water gets past. A drip means that meeting is no longer perfect.
In a conventional compression tap, the kind with a handle you wind down, the parts work like this. You turn the handle, which drives the spindle down into the tap. Around the spindle sits a gland or O-ring that stops water escaping up around the moving shaft. At the bottom of the spindle is the jumper valve, which carries a soft rubber washer. As you wind the tap closed, that washer is pressed down onto the brass seat moulded into the tap body, sealing off the flow.
A quarter-turn ceramic disc tap works on a different principle. Rather than a rubber washer pressing onto a seat, it has two polished ceramic discs stacked together, one fixed and one that rotates with the handle. A quarter turn lines up or offsets the holes in the discs to open or close the flow, and the seal is the two smooth ceramic faces meeting precisely. There is no rubber washer in this type at all, which is why it fails differently.
Dripping From the Spout: Washer and Seat Wear
If the water is coming out of the spout, the downstream seal, the one that is meant to close off the flow completely, is not doing its job. There are three usual culprits.
The most common is the rubber washer itself. Over time it hardens, splits, or compresses out of its original shape, so it no longer presses evenly onto the seat and a thin trickle gets past. Second, the jumper valve that carries the washer can sit crooked, or lose its washer entirely, so the seal is never squarely made. Third, and this is the one people miss, the brass seat can become scored or pitted. Once the seat surface is damaged, even a brand new washer cannot seal against it, because the washer is now being pressed onto an uneven surface.
This last point explains a frustration a lot of people hit: they fit a new washer, and the drip comes straight back within days. That is almost always a damaged seat. Fixing it needs a reseating tool to re-cut the seat smooth, or the seat replaced, rather than just another washer. It is worth knowing that overtightening a tap is a common cause of both washer and seat damage, since cranking the handle hard crushes the washer and hammers the seat over time. If a new washer has not held, proper tap washer replacement in Sydney includes checking and restoring the seat so the repair actually lasts.
Water Around the Handle or Base: O-Rings and Spindles
This is a different fault, and it is worth telling apart from a spout drip clearly, because it points to a different part and carries a different risk. If water is appearing at the handle, seeping out under the flange, or running down the body of the tap, the problem is not the washer. It is one of the seals on the moving shaft: a perished O-ring, worn gland packing, or a spindle whose thread has worn so the handle no longer sits square and the seal around it is broken.
Here is why this matters more than it looks. A spout drip falls neatly into the sink and down the drain, where you can see it. A handle leak often does the opposite: the water runs backward and downward, behind the tap, into the vanity, the cabinet, or worse, into the wall cavity. So a leak that looks smaller than a spout drip can actually be doing far more damage, quietly, where you cannot see it. Water tracking into a wall or cabinet this way is exactly the kind of hidden moisture that leak detection is used to trace, because by the time it shows up as a stain or a swollen cabinet base, it has usually been going for a while.
Mixer Taps and Cartridge Taps Fail Differently
A single-lever mixer tap, the kind you push up and swing side to side for temperature, has no washer to change. The entire sealing job is done by one component, the cartridge, so when a mixer fails, you are looking at the cartridge rather than any individual seal. A failing mixer usually shows itself in one of a few ways: a drip that keeps going no matter where you set the lever, a lever that feels gritty or stiff to move, or a temperature that will not hold steady and keeps drifting hot or cold.
Grit and fine debris carried in the water line are a common enemy here, because they can scratch the polished ceramic faces inside the cartridge, and once those faces are scored they no longer seal. The important practical point is that cartridges are brand and model specific. There is no universal mixer cartridge, so identifying the exact make and model is the necessary first step before the right part can be sourced.
Outdoor and laundry taps deserve a quick mention too. They tend to wear faster than indoor taps, because constant exposure to sun and frost hardens their rubber washers more quickly than the sheltered life of a kitchen or bathroom tap.
A Simple Checklist to Describe Your Fault Accurately
You do not need any tools to work out a surprising amount about your fault. Run through these five questions and you will be able to describe it precisely:
- Where is the water coming from, the spout, the handle, or the base? Spout points to the washer or seat; handle or base points to the O-ring or spindle seal.
- Does it drip constantly, or only after use? A constant drip is a failed shut-off seal; water only after use can point to a seal on the moving parts.
- Is it the hot side, the cold side, or both? This tells a plumber which tap or cartridge is at fault, and whether hot water temperature is involved.
- Is it a two-handle tap, a quarter-turn tap, or a single-lever mixer? This decides whether you are dealing with a washer, ceramic discs, or a cartridge.
- Does the handle feel loose, gritty, or hard to turn? This flags spindle or cartridge wear beyond a simple seal.
Working through those narrows the fault right down before anyone even looks at it. One clear limit, though: isolating the tap and having a look under the sink is as far as safe self-inspection goes. This checklist is for describing the fault accurately, not for dismantling the tap.
When a Drip Needs a Licenced Plumber
Some drips are past the point of a simple seal renewal, and it is worth knowing which. The job steps up when there is a scored seat that needs re-cutting, a seized spindle that will not move, a tap body that moves or rocks in the bench, a mixer cartridge that cannot be identified, no working isolation valve to shut the water off, or any drip on a tap connected to a hot water system where temperature control is part of the picture. Any of those is beyond a washer change.
It is also worth knowing the regulatory side. In NSW, most plumbing work must be carried out by a licenced plumber, and the work is certified, with NSW Fair Trading setting the licence requirements. Taps and mixers sold and installed in Australia are also covered by the WaterMark Certification Scheme, which is what ensures a replacement part or tap meets the required standard. So beyond the practical reasons, there is a compliance reason the repair is not open-ended DIY territory once it goes past the basics.
Frequently Asked Questions
Does a dripping tap mean the whole tap needs replacing?
Usually not. Most dripping taps are repaired by renewing the worn internal seal, whether that is a washer, an O-ring or a cartridge. Full replacement is generally only considered when the tap body is corroded, the seat is beyond reseating, or the parts for that model are no longer available.
Why does my tap still drip after a new washer was fitted?
Almost always because the brass seat it presses onto is scored or pitted, so a new washer cannot seal against the uneven surface. The seat needs reseating or replacing. A crooked jumper valve or the wrong washer size gives exactly the same result, so those are worth checking too.
Why is water leaking from the handle instead of the spout?
A handle leak comes from the O-ring, gland or spindle seal rather than the washer that closes the spout. This water often tracks backward into the cabinet or the wall rather than into the basin, which is why a handle leak should be looked at promptly even when it seems minor.
Can I change the washer on a mixer tap?
A mixer tap does not have a washer to change. It has a cartridge, which is the whole sealing unit, and cartridges are specific to each brand and model. So identifying the correct replacement part for your exact mixer is the first step, rather than reaching for a standard washer that will not fit.
Describing the drip is half the fix
The diagnostic rule is worth holding onto: water from the spout points to the washer or the seat, water around the handle points to the O-ring or spindle, and a dripping mixer points to the cartridge. Being able to describe which one you have, and answer those five checklist questions, genuinely saves time when the tap is looked at. If the drip has not stopped, our licenced Sydney plumbers can diagnose the fault and carry out leaking tap repairs across your home or commercial property. Get in touch with Apex Plumbing Services to arrange leaking tap repairs.
