The $8 cartridge swap that stops a dripping mixer tap

You will need

• Replacement ceramic cartridge (matching your tap brand/size) · Bunnings stocks Methven, Caroma and generic cartridges $8–$25 — photo your tap brand before going in
• Flathead screwdriver · Already at home or $5 at Bunnings
• Phillips head screwdriver · Already at home or $5 at Bunnings
• Shifting spanner or adjustable wrench · Bunnings ~$15 if you don't own one
• Plumber's grease (silicone-based) · Bunnings plumbing aisle, small tube ~$6 — do NOT use petroleum jelly, it degrades rubber
• Small bowl or towel · To catch residual water in the line

Step 1

Turn off the water supply

Find the isolation valve under the sink — it's a small slot-headed valve on the hot and cold pipes. Turn both a quarter-turn so the slot runs across the pipe. If there's no isolation valve under the sink, turn off the mains stopcock (usually in the meter box outside or under the kitchen sink).

Step 2

Pop the handle cap and remove the handle

Use a flathead screwdriver to gently pry off the decorative cap on top of the handle — it's usually just snapped on. Underneath you'll find a Phillips or hex screw; remove it and lift the handle straight off. Place the cap and screw somewhere safe like a small bowl so they don't disappear.

Step 3

Unscrew the cartridge retaining nut

You'll see a large hexagonal collar holding the cartridge in place. Use your shifting spanner to unscrew it anticlockwise — lefty loosey. Lift it off and set it aside. A little water may dribble out, so your towel is handy here.

Step 4

Pull out the old cartridge and note its orientation

Grip the cartridge and pull it straight up — it should slide out with gentle wiggling. Take a clear photo of which way the cartridge faces before removing it fully, as the new one must go back in the same orientation. Take the old cartridge to Bunnings to match it if you haven't already bought the replacement.

Step 5

Grease and seat the new cartridge

Apply a thin smear of silicone plumber's grease around the rubber seals on the new cartridge — this helps it seat properly and extends its life. Press the new cartridge in firmly, matching the orientation from your photo. It should click or sit flush with no rocking.

Step 6

Reassemble, turn water on slowly and test

Replace the retaining nut and hand-tighten, then give it a quarter-turn with the spanner — don't over-tighten or you'll crack the cartridge. Reopen the isolation valves slowly, replace the handle and cap, then run the tap and check for drips. A slow drip that settles within a minute is fine; ongoing dripping means the cartridge isn't seated — re-seat before calling anyone.

The stop point

If the tap body itself is cracked, if water is leaking from the pipe fittings under the sink, or if you cannot locate an isolation valve or mains stopcock → stop, turn off the mains if safe to do so, and call a licensed plumber.

If that is where you are: public cost guides put a leaking tap / minor leak job at $120 to $280 (sources: ServiceSeeking 2026 price guides; The Quote Yard tradie rates (Mar 2026); Airtasker cost guides (2024, handyman tier); captured 2026-07-12). See the full cost guide.

Mendy calls tradies for you. Your first booking is free, then $3.50 a booking.

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