Standard household tap washer sizes in Australia are 13mm (1/2 inch) and 15mm (5/8 inch), with 20mm and 25mm used on garden and larger taps. To fix a dripping tap, turn off the water, unscrew the tap, swap the worn washer for a matching one, and reassemble. Most jobs take 15 to 30 minutes with a shifting spanner and a screwdriver.
How do I know which tap washer size I need?
Tap washer size refers to the diameter of the washer that seats against the tap base. The two you will meet most often indoors are 13mm and 15mm. Kitchen and bathroom taps are almost always one of these.
Outdoor garden taps, hose bibs and older laundry taps often step up to 20mm or 25mm. If you are unsure, the surest method is to remove the old washer and measure it, or take it to the store and match it against a new one.
An assorted kit takes the guesswork out entirely. A mixed pack of PVC, rubber and fibre washers covers every common indoor size in one box, so you are not caught short mid-job. You will find these alongside repair kits in our plumbing range.
What are the different types of tap washers?
Not all washers are made the same, and using the right material matters for how long the repair lasts.
- Rubber washers are the classic flat washer, cheap and easy, and fine for cold-water taps that are not used constantly.
- Fibre washers handle heat better, so they suit hot taps and combined hot/cold service.
- Nylon and acetal washers resist wear and hard-water build-up, giving a longer life on high-use taps.
- Jumper valve washers combine the washer and the metal jumper into one part, common in modern tapware.
Match the material to the job and you will not be back under the sink in six months.
What you'll need
Gather your tools before you start so the water stays off for the shortest time possible.
- A shifting (adjustable) spanner
- A flat and Phillips screwdriver
- Replacement washers in the correct size and material
- Plumbers grease or petroleum jelly for the thread
- A cloth to protect chrome and catch drips
Keep a spare hardware and fasteners kit nearby too, as tap spindles sometimes hide a small circlip or O-ring that also needs replacing. A rag or old towel under the tap saves you mopping up later.
How to replace a tap washer step by step
1. Turn off the water
Shut off the isolation valve under the sink, or turn off the main tap at the meter if there is no isolator. Open the tap fully to drain any pressure and confirm the flow has stopped.
2. Remove the tap handle and body
Prise off the button on top of the handle to reach the retaining screw, then lift the handle away. Unscrew the chrome cover (the skirt) by hand, then use the spanner on the flats of the bonnet or headgear underneath. Wrap the cloth around the chrome first to avoid scratches.
3. Lift out the spindle and old washer
Wind the spindle out and turn it over. The old washer sits in a recess at the bottom, held by a small brass screw or a push-fit jumper. Note the size and shape before you remove it.
4. Fit the new washer
Undo the screw, replace the perished washer with your matching one, and do the screw back up snugly without over-tightening. If it is a jumper type, just swap the whole jumper. Smear a little grease on the spindle thread while you are there.
5. Reassemble and test
Wind the spindle back in, hand-tighten the bonnet then nip it with the spanner, and refit the cover and handle. Turn the water back on slowly and check for leaks around the base and at the spout.
Common mistakes to avoid
The most common error is over-tightening the tap when you close it, which crushes the new washer and brings the drip straight back. Turn taps off gently.
The second is fitting the wrong material, such as a plain rubber washer on a hot tap, where it hardens and fails fast. Also check the tap seat inside the body; if it is scored and pitted, a new washer alone will still drip and the seat needs re-grinding.
Finally, do not forget to open a tap somewhere before you shut the main, or you can trap pressure that sprays when you loosen the bonnet.
When should you call a plumber?
A single dripping tap is a genuine DIY job for most people. Call a licensed plumber if the tap body itself is corroded, if the isolation valve will not seal, or if you find the tap seat is badly worn and you do not have a reseating tool.
Persistent leaks after a fresh washer usually point to a seat or spindle problem rather than the washer. In some states, work beyond simple washer replacement legally requires a licensed plumber, so know your limits.
Beyond the washer: other quick tap upgrades
While the tap is apart, it is a good moment to think about water quality and comfort. A worn tap is often a sign of an older kitchen that could use a refresh.
If your drinking water tastes off, a replacement cartridge such as the BRITA On Tap Pro V-MF filter refill keeps an existing on-tap filter working like new. For benchtop and under-sink systems, the Aquaport 600L replacement filter cartridge restores flow and cuts sediment. Small parts like a 15mm chrome oval centre pillar also come in handy when you are tidying up rails and fittings around the same wet area.
Frequently asked questions
What size tap washer is most common in Australian homes?
The 13mm (1/2 inch) washer is the most common for indoor kitchen and bathroom taps, closely followed by 15mm (5/8 inch). Garden and laundry taps often use larger 20mm or 25mm washers. If unsure, remove the old washer and match it, or use an assorted kit that covers every common indoor size.
Why does my tap still drip after replacing the washer?
A drip after a new washer usually means the tap seat inside the body is worn, scored or pitted, so the fresh washer cannot seal against it. The fix is to re-grind (reseat) the tap seat with a reseating tool. Over-tightening the tap or fitting the wrong washer material can also cause it.
Can I replace a tap washer without turning off the mains?
Yes, if your tap has its own isolation valve under the sink, just close that one valve and leave the rest of the house with water. If there is no isolator, you must shut off the main tap at the meter. Always open the tap afterwards to drain pressure before you undo the bonnet.
How long does a tap washer last?
A quality washer in the right material typically lasts several years. Rubber washers on hot or high-use taps wear fastest, while nylon, acetal and fibre washers last considerably longer. Hard water, grit in the supply and over-tightening the tap all shorten a washer's life, so turn taps off gently.
