A tap drips because a seal inside it no longer closes off the water. Which seal it is, and how you fix it, depends on the kind of tap. A twist tap with a washer is a small job most people can do. A quarter-turn tap or a mixer has a cartridge that has to match, and a tap that keeps dripping after a new washer has a different problem altogether.
This guide covers how to tell your tap type, how to fix each one, why some keep dripping, and where the water is really coming from.
What kind of tap do you have?
Turn the handle from off to fully on. If it turns more than half a turn, it’s a washer tap. If it stops after a quarter or half turn, it has a ceramic disc cartridge. If one lever sets both flow and temperature, it’s a single-lever mixer, which also uses a cartridge. Each fails in its own way.
| Tap | How to tell | What wears out | The usual fix |
|---|---|---|---|
| Washer tap (older pillar, bench and wall taps, most outside taps) | The handle turns well past a half turn | The rubber washer, the brass seat it presses on, and the O-ring on the spindle | A new washer; reseating if it keeps dripping |
| Quarter-turn tap | The handle stops after a quarter or half turn | The ceramic disc cartridge and its seals | Clean or replace the cartridge with a matching one |
| Single-lever mixer | One lever controls flow and temperature | The cartridge and its seals; O-rings at a swivel spout | Clean or replace the cartridge; new spout O-rings |
A ceramic disc cartridge has two discs, one fixed and one that moves with the handle. Water flows when the openings in them line up. The discs don’t wear the way rubber does, but they won’t last forever.
How do you fix a dripping washer tap?
Turn the water off, take the handle and the headwork off, and replace the washer on the jumper valve with a new one the same size. Replace the spindle O-ring while you’re in there, then reassemble and turn the water back on. A tap repair kit has the washer, jumper valve and O-rings together.
- Turn off the water. Use the isolation valve under the basin or sink if there is one. If not, turn it off at the meter, which Bunnings notes is usually in the meter box at the front of the property. Open the tap to let the last of the water out.
- Put the plug in. Small screws and washers go down a waste easily.
- Take off the handle. Prise off the hot or cold indicator cap or button, then undo the screw underneath. Some handles have a small grub screw on the side instead. Lay the parts out in the order they came off.
- Undo the headwork. Turn the bonnet anti-clockwise with a tap spanner to expose the spindle and the jumper valve, the small part that carries the washer.
- Replace the worn parts. Fit the new washer, or a new jumper valve with its washer. Bunnings’ method replaces the O-ring and body washer at the same time and lubricates the O-ring and spindle with tap grease.
- Reassemble and test. Put it back together in reverse, turn the water on, and open the tap fully to push the air out.
Don’t overtighten the headwork or the handle to stop a drip. A washer that’s crushed out of shape leaves a path for water past it. Outside taps work the same way, although a spindle that has seized after years in the weather is best left to a plumber.
Why is my tap still dripping after a new washer?
Usually because the brass seat the washer closes against is worn or pitted. A new washer can’t seal on a rough seat, however hard you turn the handle. The fix is to reseat the tap, which grinds the seat flat again, or to fit a new seat insert if it’s too worn to grind.
With the headwork off, look into the tap body at the seat. Worn seats show small channels cut into the brass where water has been forcing its way past. Run a fingernail around the rim: if it catches, the seat needs attention.
A reseating tool screws into the tap body and cuts the seat back to a flat, smooth face. Each pass removes some brass, so a seat can only be reseated so many times. Past that point, a stainless steel seat insert or a new tap is the answer.
Two other causes are worth checking first:
- The wrong washer. A washer that doesn’t match the seat, or isn’t sitting flat on the jumper valve, won’t seal even on a good seat.
- A damaged jumper valve. One that’s bent or corroded holds the washer at an angle. Replace the jumper valve and washer together.
Why does a quarter-turn tap or mixer drip?
The cartridge isn’t sealing. Most often, grit has lodged between the discs or a seal on the cartridge has worn or split. Taking the cartridge out, cleaning it and checking its seals sometimes fixes it. If the discs are scratched or the drip comes back, the cartridge needs replacing.
To get at it, turn the water off, remove the handle (usually a cap and screw, or a grub screw), then unscrew the cover or retaining nut and lift the cartridge out. Check for grit on the discs, and for O-rings with nicks or tears. A New Zealand tapware supplier recommends an inline filter on the supply to the tap to keep grit out of the cartridge.
Replacement cartridges are the hard part. They come in many sizes and patterns, and ceramic quarter-turn valves are made left-handed or right-handed. Take the old one with you to a plumbing supplier so you get an exact match. If the tap is still under warranty, ask the supplier about a replacement cartridge before you buy one.
A mixer that drips only after the hot has been on usually has a worn hot-side seal, or a cartridge that has hardened with the heat. That’s still a repair, not a new tap, unless the tap body itself is damaged.
Shower mixers use the same kind of cartridge, with the body set into the wall. Our shower repairs page covers that work.
Where is the water actually coming from?
Watch the tap while it’s off, then while it’s running. A drip from the spout when it’s off is the washer and seat, or the cartridge. Water around the handle while it’s on, at the base of the spout, or under the bench is a different seal, and a new washer won’t touch it.
- Around the handle while the tap runs: the O-ring on the spindle, which hardens and stops sealing, or the seals on a mixer cartridge.
- At the base of a mixer’s swivel spout: the O-rings at the bottom of the spout.
- At the base of a washer tap: the body washer where the headwork screws into the tap.
- Under the bench or vanity: a connection or the flexible hoses that feed the tap. In 2017, insurer IAG said its research showed flexible hoses “only last around 10 years”. Kinks, bulges and rust on the braid are signs one is near the end.
A leak under the bench does more harm than a drip into the basin, because it can run for months before anyone notices. If you find one, turn off the isolation valve or the water at the meter and have it looked at.
How much water does a dripping tap waste?
More than it looks. Watercare says a dripping tap can waste up to 33 litres of water a day. A constant drip also stains the basin or sink under it. It won’t flood the house, but it doesn’t fix itself.
A meter that keeps turning with every tap off points to a leak you can’t see. Our guide to water leaks and who pays explains how to do a meter test, and where your side of the supply starts.
Can you fix a dripping tap yourself?
Often, yes. The Plumbers, Gasfitters and Drainlayers Board (PGDB) says that for plumbing work, you should make sure the person doing it is licensed, but it also lists jobs a homeowner can do, and that list includes “replace or repair taps, ball cocks and plugs”.
The same PGDB page lists what a homeowner may not do, including “any work involved in fixing or unfixing any pipe, plumbing fixture or appliance”, and any pipe that supplies water. If you’re not sure which side of that line a job falls on, the board’s advice for consumers sets it out, or ask a licensed plumber before you start.
Some taps are better left to a plumber anyway: specialised designs with parts that are hard to find, or wall-mounted mixers with the body behind the tiles.
Should you repair the tap or replace it?
Repair a good-quality tap: a new washer, a reseat or a new cartridge gives it years more life. Replace it if the body is damaged, if the right cartridge can’t be found, if it’s a mixer that has already failed once, or if you’re tired of the look and want tapware that suits the room.
If you’re replacing it, the new tap needs to suit the bench or basin and the water pressure at your place. Low pressure hot water is more common in older homes, and some tapware is made only for mains pressure: one New Zealand maker warns that fitting its taps to a low pressure system can compromise both performance and warranty. Your cylinder’s label says which you have. Check the tap’s specifications, or send the model to your plumber before the visit.
What we do when you call us about a dripping tap
We find which seal has failed and tell you whether it’s a repair or a new tap, with the options and the price, before we touch anything. We carry common cartridges, washers and O-rings, so a lot of tap repairs are finished on the first visit.
If the tap needs replacing, we can supply new tapware or fit one you’ve bought; send us the model first so we can check it suits the bench and your water pressure. Tapware we supply comes with the manufacturer’s warranty and ours. Under the bench, we replace tired flexible hoses and connectors, and fit isolation valves where there are none.
Every connection is checked under pressure, and we leave the area dry and tidy. Our leaking taps page covers the work in more detail.