How to Replace a Leaking Tap Washer
By Tomo — IDIY’s licensed plumber writing safe-DIY content, based in Brisbane.
Quick legal note up front: in Australia, most plumbing work must be done by a licensed plumber. The exception is replacing washers and tap handles on traditional flick-style or hot/cold compression taps, which all states allow home owners to do. Replacing cartridges, ceramic discs, mixers, anything inside a wall, anything involving the cold or hot water service line — that’s a licensed job. Stick to washers and you’re fine.
A leaking tap is the most common plumbing job in any Aussie home, and the fix is genuinely a 15-minute task with $5 in parts. Our team does these constantly when we’re called for “plumbing problems” — and most of them are washers the home owner could have done themselves. Here’s the method.
What you’ll need
- A multi-grip plier (Channellock-style) or a basin spanner for restricted spaces
- A flat-blade screwdriver and Phillips screwdriver
- A pack of assorted tap washers (any hardware shop, $3-5)
- A pack of tap O-rings (often sold together with washers)
- A clean rag and an old toothbrush
- A tea towel to cover the basin (stops dropped screws disappearing down the drain)
Step 1: Identify which tap is leaking and which way it leaks
Two leak patterns. Drip from spout = washer at the bottom of the tap stem is worn. Leak around the handle/body when running = O-ring on the spindle is worn. Often it’s both. Replacing the washer is the same job in both cases — you’ll be in there anyway, so do both at once.
Step 2: Turn off the water at the isolation valve
Most modern Aussie homes have an isolation tap under the sink or basin — a small lever or screw-style valve on the supply line. Turn it 90 degrees clockwise (lever) or wind it clockwise until it stops (screw). If you don’t have an isolation tap under the basin (older houses), you’ll need to turn off the mains at the meter box. Open the tap fully after turning off — confirms the water is actually off and drains the line.
Step 3: Cover the drain
Tea towel over the basin and into the plug hole. Small parts will fall during this job. Catching them now beats a $300 plumber callout to retrieve a screw from the trap.
Step 4: Pop the cap off the handle
Most tap handles have a small plastic cap on top with the hot/cold logo. Pry it off carefully with a flat-blade screwdriver — there’s a notch you can hook into. Underneath you’ll see a single Phillips screw.
Step 5: Unscrew and lift the handle off
Phillips screw out, lift the handle straight up. If it’s stuck (corrosion), gently rock side-to-side as you pull. Don’t lever with the screwdriver — you’ll crack the handle.
Step 6: Unscrew the bonnet and pull out the spindle
Below the handle is a brass hex bonnet. Use the multi-grip pliers or basin spanner — anti-clockwise to undo. Wrap the jaws of the pliers in a rag if the bonnet is chrome and you don’t want scratches. Once unthreaded, pull the whole spindle assembly out of the tap body.
Step 7: Replace the washer at the bottom of the spindle
At the bottom of the spindle you’ll see the rubber washer held in place with a small brass screw or jam-nut. Unscrew, pop the old washer off, fit the new one (same diameter — that’s why you bought a multi-pack), screw the retainer back. New washer should sit flat, not tilted.
Step 8: Replace the O-ring on the spindle
Look up the spindle — there’s usually one O-ring sitting in a groove on the upper section. Slide the old one off (a fingernail under the edge will lift it), wipe the groove clean with the toothbrush, slide the new O-ring on.
Step 9: Reassemble in reverse
Spindle back into the tap body, hand-tight. Bonnet back on, tighten with pliers — firm but not gorilla-tight. Handle back on, screw in, cap back on.
Step 10: Slowly turn the water back on and test
Open the isolation valve slowly — full pressure on a freshly assembled tap can blow a seal that wasn’t quite right. Run the tap for 30 seconds, then close it firmly (firm, not slammed) and watch for drips. If still dripping, the washer might be slightly the wrong size — go back and try the next size up. If leaking around the handle, the bonnet wasn’t tight enough — half a turn more.
The Tomo rule
If the tap is older than the house — or if it’s a quarter-turn ceramic-disc tap, or a mixer tap, or anything with branded cartridges — skip the DIY and call a licensed plumber. The standard washered taps that came in 80s and 90s Aussie homes are home-owner work. Anything else is a plumber job.
Got a leak you can’t figure out — under-sink, in-wall, or a tap that’s not standard? Send us a photo — we’ll diagnose and tell you whether it’s DIY or a licensed call.
