What tools do I need for replace a ceramic disc tap cartridge?

This guide includes a comprehensive tools list. Key plumbing tools are detailed in the Tools Required section.

What size ceramic disc cartridge do I need for my Australian mixer tap?

Most Australian domestic flick mixers use either a 35 mm or 40 mm diameter ceramic disc cartridge. To ensure the correct replacement, isolate the water, remove the handle, and measure the cartridge barrel width using vernier calipers. Note whether the base features raised locating lugs or a flat profile, compliant with AS/NZS 3718 specifications.

What is the Australian standard for domestic tapware and cartridges?

The primary Australian standard governing tapware is AS/NZS 3718 (Water supply — Tap sets), enforced through the Plumbing Code of Australia. All replacement cartridges and integral rubber seals must also satisfy AS/NZS 4020, ensuring materials do not leach harmful compounds or alter the taste, odour, or safety of drinking water supplies.

Can I replace a ceramic tap cartridge myself in Australia?

In most Australian states and territories, replacing a tap washer or drop-in ceramic cartridge on an existing fixture is considered basic maintenance permitted for homeowners. However, any modification to underlying pipework or replacement of concealed wall breeching requires a licensed plumber under AS/NZS 3500 and state licensing frameworks such as the Victorian Building Authority or NSW Fair Trading.

Why is my mixer tap still dripping after installing a new cartridge?

A mixer tap that continues dripping after cartridge replacement typically indicates an unseated base O-ring, residual debris in the brass body, or incorrect retaining nut torque. Debris prevents the ceramic plates from sealing under line pressure. Remove the cartridge, clean the brass seat using household vinegar, ensure old seals are removed, and retighten to 8 to 12 Nm.

How to replace a ceramic disc tap cartridge

Quick answer

To replace a ceramic disc tap cartridge, isolate the hot and cold water supplies, lever off the indicator button, loosen the hex grub screw, and remove the handle. Unscrew the dome dress ring and brass locknut to swap the worn 35 mm or 40 mm cartridge, ensuring compliance with AS/NZS 3718.

Skill level: Beginner
Time: 30 to 45 minutes
Trade: Plumbing
Updated: 6 November 2026

Tools you will need

Hex key set
Small flathead screwdriver or precision pick
Shifting spanner / adjustable wrench
Multi
Microfibre cleaning cloth
Old toothbrush or small nylon wire brush
Flashlight or headlamp

🔧 Replacing a Ceramic Disc Mixer Tap Cartridge: Complete Australian Trade Guide

Why is your mixer tap leaking from the handle or spout?

A dripping flick mixer or stiff tap handle in a modern Australian home is almost always caused by a worn or calcified ceramic disc cartridge rather than a traditional rubber jumper valve. Replacing the cartridge restores smooth operation, stops leaks, and protects water efficiency without requiring a complete fixture replacement. This guide outlines how to safely disassemble the mixer, source the correct replacement cartridge, and reinstall it to manufacturer standards.

Skill Level

Beginner — Estimated time: 30 to 45 minutes

What tools do you need to replace a ceramic disc tap cartridge?

🔧 Tools Required

Hex key set (specifically 2.5 mm or 3 mm metric Allen keys) Small flathead screwdriver or precision pick (for removing the decorative indicator cap) Shifting spanner / adjustable wrench (minimum jaw opening to fit up to 36 mm brass locking nuts) Multi-grip pliers (plumber's grips with rubber/soft jaws preferred to prevent scratching tapware) Microfibre cleaning cloth Old toothbrush or small nylon wire brush Flashlight or headlamp

What materials and cartridge sizes are required under Australian standards?

🪵 Materials
Replacement ceramic disc cartridge (most common Australian domestic sizes are 35 mm or 40 mm diameter; flat-bottomed or raised-leg profiles complying with AS/NZS 3718) Food-grade silicone plumbing lubricant / grease (approved to AS/NZS 4020 for contact with drinking water) Clean household vinegar or descaling solution (to remove limescale from the mixer body cavity) Clean rag or paper towels

How do you safely isolate water pressure before disassembling a mixer tap?

⚠️ Safety
Scald Hazard: Domestic hot water can be stored at 60°C or higher and delivered via tempering valves at 50°C under AS/NZS 3500.4. Ensure the hot water supply is fully isolated and pressure is bled completely before disassembly. Eye Protection: Wear safety glasses when cleaning calcified brass cavities to prevent mineral chips or cleaning agents splashing into the eyes. Drain Blockage: Always insert the basin or sink plug before removing tiny grub screws; loose fasteners easily fall down the 40 mm or 50 mm fixture trap.

🔒 Licensing

Plumbing work in Australia must be performed by a licensed plumber. This guide explains the process and helps you select the right tools and materials. In many Australian jurisdictions, replacing serviceable tap components (like washers and cartridges) is considered minor maintenance, but any work altering pipework, replacing rough-ins, or adjusting tempering valves requires a licensed professional regulated under state bodies such as NSW Fair Trading, VIC VBA, QLD QBCC, or the WA Building Commission in compliance with the Plumbing Code of Australia (PCA) and AS/NZS 3500.

Step-by-Step Guide

Step 1: 1️⃣ Isolate the Water Supply and Relieve Pressure

Locate the mini cistern cocks / isolating stop valves directly under the sink or basin (typically connected to 15 mm flexible braided hoses). Turn both the hot and cold isolation taps clockwise until completely closed. If under-sink mini stops are not installed, shut off the mains water control valve at your water meter outside. Lift the flick mixer handle to the fully open, central position to drain any residual water and relieve standing pressure from the line. Fit the sink waste plug to catch dropped parts.

Step 2: 2️⃣ Remove the Hot/Cold Indicator and Handle

Use a fine-tipped flathead screwdriver or utility pick to gently pry out the small round plastic Hot/Cold indicator plug located on the front or underside of the tap lever. Look into the exposed cavity using a torch to locate the grub screw. Insert the correct size metric hex key (commonly 2.5 mm or 3 mm) and loosen the screw by turning counter-clockwise 2 to 3 full turns (do not remove it completely, as it is easy to lose). Firmly pull the tap handle upwards and off the cartridge stem.

Step 3: 3️⃣ Remove the Decorative Dress Ring and Locking Nut

Unscrew the smooth, dome-shaped decorative dress flange directly below the handle by hand. If it is stuck with limescale, wrap a microfibre cloth around it and use soft-jaw multi-grips with very light pressure to avoid denting the thin brass casing. Once the dome is removed, you will expose the heavy brass cartridge retaining nut. Adjust a wide-jaw shifting spanner to fit the flat edges of the nut firmly and rotate counter-clockwise to loosen and remove it.

Step 4: 4️⃣ Extract the Old Cartridge and Inspect the Mixer Body

Pull the ceramic disc cartridge straight up out of the tap body. If it resists, gently wiggle the plastic spindle while pulling upwards. Inspect the base of the brass tap chamber with a torch. Ensure the old rubber seals came out attached to the old cartridge and are not stuck to the bottom of the housing. Clean any grit, mineral deposits, or corrosion out of the internal cavity using an old toothbrush dipped in vinegar, then wipe the chamber dry with a clean cloth.

Step 5: 5️⃣ Source and Prepare the Correct Replacement Cartridge

Take the old cartridge to your local plumbing supplier to ensure a precise match. Modern mixers in Australia typically use either a 35 mm or 40 mm diameter cartridge, available in standard flat-base or raised locating-lug styles. Check that the locating pins on the base match the alignment holes inside your tap casting. Lightly coat the new rubber base O-rings with a thin smear of AS/NZS 4020 approved food-grade silicone grease to prevent pinching during installation.

Step 6: 6️⃣ Install the New Cartridge and Reassemble

Insert the new cartridge into the mixer body, rotating it slightly until the locating pins drop cleanly into the corresponding alignment holes at the base of the tap casting; the cartridge should sit completely flat without rocking. Thread the brass retaining nut on by hand to avoid cross-threading, then tighten with your shifting spanner. Do not overtighten—firm hand-tight pressure with a quarter-turn past snug is sufficient to compress the rubber seals without binding the internal ceramic discs. Thread the decorative dome cover back on by hand.

Step 7: 7️⃣ Reinstall Handle, Restore Water, and Test

Slide the handle back onto the square cartridge stem. Tighten the internal grub screw using your hex key until secure, then push the plastic indicator plug back into place. Slowly turn the isolating valves under the sink (or mains meter) back on counter-clockwise to prevent hydraulic shock (water hammer). Test the flick mixer across both full hot and full cold positions, verifying smooth handle resistance and checking around the dress ring and under the sink for leaks.

Common Mistakes to Avoid

1.Overtightening the Brass Retaining Nut: Applying excessive torque crushes the ceramic discs inside the cartridge housing, resulting in a stiff, difficult-to-move handle and premature failure of the internal mechanism.

2.Leaving Old Seals Inside the Chamber: The base O-rings can detach from the old cartridge and remain wedged in the bottom of the tap body. Installing a new cartridge on top of old seals causes poor alignment, thread damage, and severe leaks.

3.Using Petroleum-Based Lubricants: Applying petroleum jelly (Vaseline) or automotive grease degrades EPDM rubber seals and contaminates the potable water supply. Only use lubricants certified to AS/NZS 4020.

4.Cross-Threading the Retaining Ring: The fine brass threads on the mixer body and locknut strip easily if forced. Always start the thread by hand counter-clockwise until you feel the thread click, then spin clockwise.

Pro Tips

💡 Check Your WELS Rating: Replacing an older leaking mixer with a modern unit rated at 4-star, 5-star, or 6-star WELS (Water Efficiency Labelling and Standards) can reduce tap flow from 15 L/min down to as low as 4.5 to 7.5 L/min, saving substantial water and energy. 💡 Take the Old Part to the Trade Counter: Australian tapware uses dozens of subtly different cartridge profiles (e.g., standard, high-flow, raised base, short stem from brands like Caroma, Dorf, Methven, and Phoenix). Take the old cartridge to the plumbing trade counter to guarantee a match. 💡 Inspect Flexible Hoses: While under the sink, inspect your 15 mm stainless steel braided flexi connectors. If they show any signs of bulging, fraying, or rust spots, or are over 5–10 years old, have them replaced by a licensed plumber to prevent catastrophic burst pipe flooding. 💡 Flush the Line Before Final Tightening: If sediment was present in your pipework, you can temporarily pop the cartridge out and briefly crack open the isolation valves to flush out debris that could otherwise score the new ceramic plates.

Recommended Tools

Bahco 9031 Wide Jaw Adjustable Wrench (200 mm): Slim jaws with a massive 38 mm opening, ideal for accessing recessed mixer locknuts without chewing soft brass. Bondhus Metric Ball-End Hex Key Set: Ball ends allow angled access into cramped grub screw pockets beneath curved tap levers.

Knipex Cobra Soft-Jaw Plumber's Pliers: Specially fitted plastic jaw inserts that grip polished chrome and matte black tap dress rings without scratching decorative finishes.

Frequently asked questions

What is involved in replace a ceramic disc tap cartridge?: A dripping flick mixer or stiff tap handle in a modern Australian home is almost always caused by a worn or calcified ceramic disc cartridge rather than a traditional rubber jumper valve. Replacing the cartridge restores smooth operation, stops leaks, and protects water efficiency without requiring
What skill level do I need for replace a ceramic disc tap cartridge?: Beginner — Estimated time: 30 to 45 minutes
What are common mistakes when replace a ceramic disc tap cartridge?: 1. Overtightening the Brass Retaining Nut: Applying excessive torque crushes the ceramic discs inside the cartridge housing, resulting in a stiff, difficult-to-move handle and premature failure of the internal mechanism. 2. Leaving Old Seals Inside the Chamber: The base O-rings can detach from the old cartridge and remain wedged in the bottom of the tap body. Installing a new cartridge on
What tools do I need for replace a ceramic disc tap cartridge?: This guide includes a comprehensive tools list. Key plumbing tools are detailed in the Tools Required section.
What size ceramic disc cartridge do I need for my Australian mixer tap?: Most Australian domestic flick mixers use either a 35 mm or 40 mm diameter ceramic disc cartridge. To ensure the correct replacement, isolate the water, remove the handle, and measure the cartridge barrel width using vernier calipers. Note whether the base features raised locating lugs or a flat profile, compliant with AS/NZS 3718 specifications.
What is the Australian standard for domestic tapware and cartridges?: The primary Australian standard governing tapware is AS/NZS 3718 (Water supply — Tap sets), enforced through the Plumbing Code of Australia. All replacement cartridges and integral rubber seals must also satisfy AS/NZS 4020, ensuring materials do not leach harmful compounds or alter the taste, odour, or safety of drinking water supplies.
Can I replace a ceramic tap cartridge myself in Australia?: In most Australian states and territories, replacing a tap washer or drop-in ceramic cartridge on an existing fixture is considered basic maintenance permitted for homeowners. However, any modification to underlying pipework or replacement of concealed wall breeching requires a licensed plumber under AS/NZS 3500 and state licensing frameworks such as the Victorian Building Authority or NSW Fair Trading.
Why is my mixer tap still dripping after installing a new cartridge?: A mixer tap that continues dripping after cartridge replacement typically indicates an unseated base O-ring, residual debris in the brass body, or incorrect retaining nut torque. Debris prevents the ceramic plates from sealing under line pressure. Remove the cartridge, clean the brass seat using household vinegar, ensure old seals are removed, and retighten to 8 to 12 Nm.

Written by Pipey, the Plumbing specialist at VIC.Tools.