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Leaking Tap: How to Fix It Yourself (Australian Guide)
Leaking Tap: How to Fix It Yourself (Australian Guide) — a Prime Plumbing & Gasfitting plain-English guide to leaking tap how to fix for Melbourne homeowners. Below we cover what works, what doesn't, and when to call a licensed plumber.
Quick answer: A dripping tap is almost always one of two things — a worn rubber washer in a traditional compression tap (the old-style ones with separate hot/cold handles), or a worn cartridge in a modern mixer tap (single lever for hot/cold). Washer replacement on a compression tap takes 20 minutes and costs about $5 in parts. Cartridge replacement on a mixer takes 30–40 minutes and costs $35–$120 depending on brand. The big DIY barriers are: (1) shutting off the water properly, (2) getting the right size washer or correct-brand cartridge, (3) handling stuck spindle nuts on older taps. If your tap is more than 20 years old or you're dealing with a wall-mounted bath spout, sometimes it's faster to call a licensed plumber — typical callout for a tap repair is $130–$220.
First, identify what kind of tap you have
The fix is completely different depending on tap style:
Compression / quarter-turn tap (older style, two handles)
Two separate handles — one for hot, one for cold. You turn each one a half-turn or full-turn to open. The handle screws down onto a rubber washer that seals against a brass seat. When the washer wears out, water leaks past it.
You see these on:
- Garden taps (the screw-handle kind)
- Older laundry tubs
- Some older bathroom basin sets and bath sets
- Most pre-1990s wall mixers (if they're separate hot/cold)
Mixer tap (modern style, single lever)
Single handle that moves up/down for flow and side-to-side for temperature. Inside is a cartridge — usually ceramic disc — that controls both flow and mix. When the cartridge wears, water leaks past the discs even when the handle is fully closed.
You see these on:
- Most modern bathroom basin taps
- Most modern kitchen taps
- Modern shower mixers
- Modern bath spout mixers
Quarter-turn ceramic tap (in-between, older mid-older homes)
Looks like a compression tap (separate hot/cold handles) but turns a quarter-turn only. Inside is a ceramic disc cartridge instead of a rubber washer. Repair is similar to compression but you replace the whole spindle/cartridge instead of just a washer.
Compression tap repair (rubber washer replacement)
Tools and parts you'll need
- Adjustable wrench or shifter (10" or 12")
- Multi-tip screwdriver (Phillips and slotted)
- Allen keys (some handles use grub screws)
- Replacement washers — buy a mixed pack at Bunnings ($4–$8). Common sizes: 1/2" (12mm), 3/4" (20mm)
- Optional but useful: tap reseating tool ($25 at Bunnings), used if the brass seat is rough
Step-by-step
1. Shut off the water supply
- For a basin/bath/laundry tap: look under the basin or in the cabinet. There's usually an isolation valve on each hot/cold supply line. Turn quarter or half-turn clockwise until firm.
- If there's no isolation valve, you'll need to turn off the water at your property's main shutoff (front of property near the meter). This affects the whole house.
2. Open the tap to drain pressure
Open the tap fully so any remaining water drains out and the line depressurises. Confirm it's actually off — water should stop flowing within a few seconds.
3. Remove the handle
- Pop off the small decorative cover/cap on top of the handle (usually a button labelled "H" or "C" for hot/cold)
- Underneath you'll see a screw — remove it (Phillips or slotted)
- Lift the handle off
If the handle is stuck (mineral build-up), wiggle gently while pulling. Don't pry hard or you'll snap something. Vinegar overnight on the spindle helps loosen calcium build-up.
4. Remove the spindle
- The spindle nut is the hex nut that the spindle threads through, holding it to the tap body
- Use the adjustable wrench to unscrew it counter-clockwise
- Older taps where the nut hasn't been moved in 20+ years can be very stuck — apply penetrating oil (WD-40 specialist), wait 30 minutes, try again
- Once the nut is free, lift the spindle out
5. Inspect the washer
At the bottom of the spindle is the rubber washer, held in place by a brass screw. The washer should be flat, smooth, and round. If it's dished, cracked, hardened, or has a "groove" worn into one face — that's your leak.
6. Replace the washer
- Unscrew the brass washer screw
- Lift the old washer off
- Press the new washer (matching size) onto the brass disc
- Tighten the brass screw firmly but don't crush the rubber
7. Check the brass seat (the surface inside the tap body that the washer presses against)
Run your finger over the seat. If it's rough, pitted, or uneven, that's why the new washer will leak too. You need to reseat it — use a reseating tool to gently grind the seat smooth. This is the part where many DIY repairs fail. If the seat is badly damaged, the whole tap body needs replacement (plumber call).
8. Reassemble
- Spindle back into the tap body
- Spindle nut on, tightened firmly (not over-tight or you'll strip the threads)
- Handle back on, screw in
- Decorative cap back on
9. Restore water and test
- Open the isolation valve slowly
- Watch for leaks at the spindle nut
- Test that the tap shuts off completely
Mixer tap cartridge replacement
Tools and parts you'll need
- Adjustable wrench
- Allen key set (most mixer handle grub screws are 2.5mm or 3mm)
- Replacement cartridge — brand-specific. Bring photos of your tap to a plumbing supplier (Reece, Tradelink) or measure carefully. Methven, Caroma, Phoenix, Mizu, Linsol, Dorf, GareTH, GROHE — they all have proprietary cartridges
- Plumber's grease (silicone-based, not petroleum) — $8 small tube
- Patience — first-time mixer cartridge replacements take longer than expected
Step-by-step
1. Identify the brand and model of your mixer
Look on the underside of the spout or the flange around the base. Sometimes it's etched lightly. If you can't find branding, take detailed photos to a plumbing supplier — they often recognise common models.
2. Shut off water at the isolation valves (same as compression — usually under the basin)
3. Remove the handle
- Most mixer handles have a tiny grub screw on the underside or back, accessed with an Allen key
- Loosen the grub screw (don't remove it fully)
- Lift the handle off
4. Remove the decorative trim/skirt
- Usually unscrews counter-clockwise by hand
- Or has a small screw underneath if it's a complex skirt
- Remove to expose the cartridge retaining nut
5. Remove the cartridge retaining nut
- This is the large hex or knurled nut holding the cartridge in place
- Use the adjustable wrench, counter-clockwise
- Lift the cartridge straight up and out
6. Install the new cartridge
- Match orientation — most cartridges have a notch or slot on the body that aligns with a matching feature in the tap body
- Apply a thin film of plumber's grease to O-rings
- Press the new cartridge straight down into the seat
- Tighten the retaining nut firmly but don't over-tighten (you'll crack ceramic discs)
7. Reassemble — skirt, handle, grub screw
8. Restore water and test — check for leaks at the base of the spout, around the handle, and from the tap itself when fully closed
What to do if the spindle nut won't budge
This is the most common reason a DIY tap repair stalls. Options:
- Penetrating oil + 30-minute wait + try again (works 70% of the time)
- Heat (hair dryer, not direct flame) on the brass nut for 60 seconds, then try while warm
- Box-end socket instead of adjustable wrench — gives a square-on grip and won't slip
- Tap pinch wrench (specialist tool, $40 at Bunnings) — purpose-built for stuck spindle nuts
If after all this it still won't move, the spindle has likely fused into the tap body via mineral deposits. Stop here and call a plumber — pushing harder risks snapping the spindle off inside the tap body, which turns a $130 repair into a $400 replacement.
When the fix doesn't hold
You replaced the washer or cartridge and the tap is still leaking. Common causes:
- Brass seat damaged — needs reseating or tap replacement
- Hairline crack in tap body — visible only under pressure, requires replacement
- Cartridge supplied wasn't the exact correct part — different cartridges look identical but have different seal heights
- High mains pressure (above 500 kPa) wearing washers/cartridges quickly — pressure-limiting valve fixes this
- Spindle worn — common on 25+ year old taps; replace the spindle, not just the washer
When to call a plumber
DIY-safe scope: shutting off isolation valves, replacing washers and cartridges, basic spindle work.
Call a licensed plumber when:
Tap repair callouts in Melbourne are typically $130–$220 including parts. Tap replacement is $200–$450 depending on style.
Frequently asked questions
Bring the old washer to the hardware store. Most household taps use 12mm or 20mm washers. The mixed packs at Bunnings cover all common sizes for $4–$8 — cheaper to buy a pack than guess.
Almost always the washer (compression tap) or cartridge (mixer). Both fail in this exact pattern — water leaks past the closed seal.
Spout O-ring or aerator issue. Leaks during use usually mean water is escaping from a joint that's only stressed under flow. O-rings around the spout where it meets the body, or aerator threads, are the usual culprits. Cheap and easy to replace.
Try the gentle wiggle-and-pull first. If that fails, vinegar soaking overnight (saturate a cloth, drape over the handle base) loosens calcium. If still stuck, a handle puller (Bunnings, $20) gives leverage without prying. Never use a hammer.
Depends on the tap. Quality brass compression taps (Roca, GareTH older style) are worth fixing — they're often better quality than budget mixers. Cheap chrome compression taps are typically not worth multiple repairs — at $25 in washers across 5 years, you're better off upgrading to a quality mixer.
Either the cartridge is over-tightened (loosen the retaining nut a quarter-turn), or you didn't apply plumber's grease to the O-rings (apply now), or it's a slightly wrong-spec cartridge that's binding. Compare carefully against the old one.
5–10 years on average for a compression tap on a regularly-used basin. High-pressure systems wear them faster. Garden taps with sandy water can wear them in 2–3 years. Mixer cartridges last 8–15 years typically.
Hot water is harder on rubber and ceramic seals. Both wear faster on the hot side, so you'll usually replace hot-side washers/cartridges twice as often.
Before You Book
A quick checklist to share with your plumber when you book:
- When did the issue start?
- Is it isolated to one fixture or multiple areas?
- Are there any visible leaks, smells or unusual sounds?
- Have you turned off the relevant isolation valve?
For tap repairs that have outgrown DIY scope, see our Leaking Tap Repairs Melbourne page. For toilet issues that often pair with tap problems in older bathrooms, see our Toilet Repairs Melbourne page. For a property-wide plumbing inspection — useful if you're seeing multiple worn taps as a sign of aging plumbing — contact us.
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