How to replace a basin mixer tap

🔧 Basin mixer tap replacement guide for Australian plumbing work

What is involved in replacing a basin mixer tap in Australia?

Replacing a basin mixer tap is a routine plumbing task that typically involves isolating the water supply, removing the existing mixer, preparing the basin seating surface, installing the new mixer, reconnecting flexible tap connectors, and commissioning the fixture for leaks and correct operation. 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.

This work should be completed in accordance with the PCA, AS/NZS 3500 requirements for water services, and manufacturer installation instructions. Where isolation valves, mini stops, tempering arrangements, or deteriorated flexible connectors are non-compliant or unserviceable, they should be rectified as part of the job.

What skill level is required for basin mixer tap replacement?

Intermediate — Estimated time: 1 to 2 hours

What tools are required for basin mixer tap replacement?

What materials are needed for a basin mixer tap replacement?

Safety Requirements

Step-by-Step Guide

Step 1: Assess the existing installation

Inspect the basin mixer configuration, vanity access, and connection type before starting. Confirm whether the existing mixer uses flexible braided hoses, copper tails, or integrated PEX-style tails, and identify the condition of the existing 15 mm isolation valves.

Check for:

💡 Where the existing mini stops are seized or weeping, quote to replace them during the same visit rather than reconnecting to suspect valves.

Step 2: Isolate and drain the water services

Close the local isolation valves under the basin. If local valves are not fitted or are inoperative, isolate at the nearest branch line or main water supply as required.

Open the mixer to release pressure from both hot and cold supplies. Move the lever through full hot and cold positions to ensure both lines are depressurised. Place a bucket and towels beneath the work area before disconnecting any hoses.

Step 3: Disconnect the existing mixer connections

Using an adjustable spanner or suitable tool, disconnect the hot and cold flexible connectors from the isolation valves. Retain or replace washers according to the connector type and manufacturer requirements.

If a pop-up waste linkage is present and obstructing removal, disconnect the trap linkage or waste rod components as needed. Keep all removed components organised, particularly if reusing the waste assembly.

Step 4: Remove the old basin mixer

Access the underside of the basin or vanity top and undo the mixer retaining nut, horseshoe bracket, or proprietary fixing assembly using a basin spanner, box spanner, or deep socket. Once the fixing is released, withdraw the mixer body from above.

Remove any old putty, silicone residue, or degraded foam seals from the basin surface. Clean the seating area thoroughly so the new base seal can sit flat and watertight.

💡 On stone tops and fine ceramic, use only plastic scrapers and non-abrasive cleaner to avoid scratching finished surfaces.

Step 5: Inspect and prepare the mounting area

Check the basin tap hole for chips, cracking, out-of-round wear, or distortion that may prevent correct sealing. Confirm the basin or vanity top is structurally sound and that the mixer base will fully cover the existing footprint.

Test fit the new mixer and ensure:

Step 6: Install the new basin mixer

Feed the inlet tails and threaded fixing stud through the basin tap hole. Position the mixer square to the basin and align the spout centrally.

From below, install the gasket, stabilising plate, horseshoe washer, and backnut as supplied. Tighten progressively while maintaining alignment from above. Do not overtighten, especially on vitreous china basins, as excessive load can crack the fixture or distort the mixer base.

If the manufacturer specifies silicone under the base, apply a neat minimal bead of neutral cure sanitary silicone. Most modern mixers use a supplied base seal rather than relying on silicone alone.

Step 7: Reconnect hot and cold water services

Connect the mixer tails to the isolation valves, ensuring hot connects to the left and cold to the right unless the product specifies otherwise. Hand-start all threads to avoid cross-threading.

Tighten connectors to manufacturer specification. Braided flexible connectors must not be:

If replacing isolation valves, install approved valves suitable for DN15 / 15 mm connections and test before final reconnection. Use thread sealing only on approved male threaded joints, not on face-seal or washer-seal unions unless specified.

Step 8: Reinstate supply and pressure test

Slowly reopen the isolation valves or main supply and monitor the mixer tails, valve connections, and mixer base for immediate leakage. Keep the mixer in the open position initially to purge air from the lines, then cycle the lever through hot and cold.

Run water for several minutes and inspect:

Use dry tissue around each connection to identify fine weeps that may not be visible.

Step 9: Commission the fixture and complete handover

Check flow performance, handle operation, spout alignment, splash control, and temperature orientation. Confirm the mixer returns smoothly to the off position and there is no cartridge chatter or water hammer-related noise.

If the mixer includes or was supplied with a waste, test the pop-up operation and trap seal after reassembly. Clean the fixture, remove packaging, record model/WELS details where required, and hand over operation and maintenance information to the client or builder.

Common Mistakes to Avoid

Pro Tips

Recommended Tools

🔒 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. Compliance obligations vary by state and territory, with licensing administered by NSW Fair Trading, VIC VBA, QLD QBCC, and WA Building Commission.