How to Install an Under-Sink Water Filter in Australia: A Complete Guide

Installing an under-sink water filter is one of the best upgrades you can make to your kitchen’s drinking water. Here’s a complete guide — including what requires a licensed plumber in Australia and what you can do yourself.

See our Under Sink Water Filters Guide or browse our under-sink filter range.

Step 1: Choose the Right System

Consider these factors when selecting your under-sink filter:

• Filtration type: Standard inline carbon filter (removes chlorine, sediment), multi-stage filter (broader contaminant removal), or reverse osmosis (highest level including fluoride). See our RO Guide if fluoride removal is a priority.
• Dedicated tap or existing tap: Some systems use a diverter on your existing tap; others require a dedicated filtered water tap drilled through the sink or benchtop.
• Flow rate: Ensure the system’s rated flow rate suits your household’s usage.
• Cartridge availability: Check that replacement cartridges are readily available. Browse our replacement cartridge range.

Step 2: What Requires a Licensed Plumber (Important)

In most Australian states, any work involving cutting into or connecting to a pressurised cold water supply line must be done by a licensed plumber. This is a legal requirement — not just a recommendation. DIY plumbing on pressurised lines can void your home insurance and is illegal in some states.

A licensed plumber will: shut off the cold water supply, install a T-fitting or saddle valve on the cold water line, connect the filter inlet line, and install a dedicated filtered water tap if required. This is typically a 1–2 hour job.

Step 3: What You Can Do Yourself (Before the Plumber)

• Choose the installation location under the sink — ensure there’s enough space for the filter housing and easy access for cartridge changes
• Install the mounting bracket on the cabinet wall (drill pilot holes, attach with provided screws)
• Assemble the filter housing: seat the O-ring, apply a small amount of silicone grease, install the cartridge
• If a dedicated tap is required, drill the tap hole through the sink or benchtop before the plumber arrives

Step 4: After the Plumber Connects the Water Lines

Once the plumber has made the water line connections:

1. Flush the system: Turn on the filtered water tap and run water for 5–10 minutes to flush any residual carbon dust or manufacturing debris from the new cartridge. The water may appear grey or cloudy initially — this is normal.
2. Check all connections for leaks: Inspect every connection point. If you see any dripping, turn off the water supply and tighten the connection.
3. Set a cartridge replacement reminder: Note the installation date and set a calendar reminder for 6–12 months’ time.

Step 5: Ongoing Maintenance (DIY-Friendly)

Cartridge replacement does not require a plumber — use the shut-off valve on the filter inlet line to isolate the filter, unscrew the housing, swap the cartridge, and restore flow. Replace every 6–12 months. Browse our replacement cartridge range.

Frequently Asked Questions