A dripping tap might not seem urgent at first. Then the water bill arrives, or you open the cupboard under the sink and find everything damp. Fixing a leaking mixer tap promptly can help prevent wasted water and lower your water bill over time.
Unlike old-style taps that rely on a rubber washer, most modern mixer taps use a ceramic cartridge with internal seals and O-rings to control flow and temperature through a single handle. That difference changes how the repair works.
Wondering what happens during a leaking mixer tap repair? Here’s what to expect.
Why Mixer Taps Start Leaking
Mixer taps have several moving parts packed into a compact fitting, and daily use eventually wears them out. Often, the culprit is a worn ceramic cartridge. It allows water to pass through even after the tap has been turned off.
Other leaks come from ageing O-rings, hardened seals, or mineral deposits stopping parts from sealing properly. Apart from the tap itself, common causes include a loose fitting, cracked tap body, or worn flexible hose under the sink.
Spout Drips, Base Leaks, and Under-Sink Leaks
A drip from the spout after the tap is off usually points to the cartridge or another internal seal. Water around the base often comes from worn O-rings in the swivel section, though it can also be travelling down from a leak higher up.
If the cupboard under the sink is wet, the tap body may not be the issue at all. The plumber will then check flexible hoses, compression fittings, isolation valves, and supply connections. When asked, it’s important that you describe where you first noticed the water, so your leaking tap plumber can narrow the possibilities before the inspection even begins.
Why Mixer Taps Aren’t Repaired Like Old Washer Taps
Years ago, a dripping tap often meant replacing a rubber washer. It was a familiar repair and, in many homes, a regular weekend job.
Mixer taps are built differently. Instead of separate hot and cold tap assemblies with washers pressing against valve seats, most mixer taps use a ceramic cartridge that controls temperature and water flow through one handle.
Because of that design, replacing the wrong component may do little more than empty your wallet. Even cartridges that look almost identical can have different dimensions, locating tabs, or flow characteristics depending on the manufacturer.
What a Licensed Plumber Checks First
Before dismantling the tap, the plumber identifies the make and model so the correct replacement parts can be sourced if needed. Then, they pinpoint the leak: Is it from the spout, the base, or under the sink? Constant or only while running?
Handles are checked for excess movement. The mixer tap cartridge is assessed, and seals, hoses, and fittings are also examined for wear or corrosion. If the leak is long-standing, nearby cabinetry and benchtops are checked for water damage.
Just as crucial is water pressure. Excessively high pressure won’t cause every leaking mixer tap, but it can shorten the life of cartridges, seals, and flexible hoses. If similar plumbing fittings have failed more than once, pressure testing may also be needed.
Testing the Water Supply and Isolation Valves
Before any repair starts, the water must be isolated safely. Many homes have mini stop taps under the sink that let repairs proceed without cutting water to the whole house.
Older valves don’t always cooperate. Some seize with age, while others begin leaking as soon as they’re turned. If that happens, the plumber may need to isolate the property’s main water supply before continuing. This is one of the reasons DIY repairs don’t always go to plan. If an ageing isolation valve reaches its end of life, a simple cartridge replacement can get complicated.
Checking for Water Damage Around the Tap
Water can run behind the sink, track along the underside of a benchtop, or slowly soak into cabinetry without being obvious from above. Over time, laminate may swell, silicone joints can deteriorate, and moisture may spread into surrounding materials.
Before finishing the inspection, a plumber will usually dry the affected area, trace any signs of moisture, and then retest the tap to confirm exactly where fresh water appears.
How the Tap Is Disassembled Safely
Once the cause of the leak has been narrowed down, it’s time to take the tap apart. While the exact process varies between brands and models, licensed plumbers generally follow a careful sequence to avoid damaging the tap or surrounding surfaces.
- Remove the handle – This usually involves loosening a small grub screw hidden beneath a decorative cap. Once the handle is off, the internal components become accessible.
- Access the cartridge – The retaining nut and other fittings are removed carefully. Because every manufacturer designs mixer taps a little differently, there’s no universal method that suits every tap.
- Protect the tap’s finish – Chrome and brushed metal surfaces can scratch more easily than many people expect. A plumber uses suitable tools and avoids forcing seized parts, reducing the risk of damaging the tap body.
- Inspect each component – As the tap is dismantled, every part is checked for wear. O-rings are inspected for splits or flattening, while the ceramic cartridge is examined for wear, mineral build-up and other signs that it has reached the end of its service life.
- Identify the correct replacement parts – The components removed are used to match the right cartridge, seals or O-rings. Many mixer taps look almost identical from the outside but use different internal parts, so choosing the correct replacement is an important part of a lasting repair.
Replacing the Mixer Tap Cartridge, Seals, or O-Rings
Many leaking mixer taps don’t need replacing. Quite often, fitting a new ceramic cartridge, seal, or O-ring restores the tap to normal operation.
The replacement part has to suit the tap exactly. Locator pins need to line up correctly, sealing surfaces must sit flush, and the cartridge has to match the original design. Be careful, because even a slight variation can prevent the tap from sealing properly.
Where recommended by the manufacturer, seals are lubricated with an appropriate plumbing grease before the tap is reassembled. This helps the components seat correctly and allows the handle to move smoothly without placing unnecessary strain on the seals.
Many plumbers carry a selection of common cartridges and seals in their vehicles. If the tap uses an uncommon brand or an older design, the correct part may need to be ordered before the repair can be completed.
When a Cartridge Replacement Solves the Leak
Certain symptoms often point towards a worn cartridge. While only an inspection can confirm the exact cause, plumbers commonly suspect the cartridge when they notice one or more of the following:
- A steady drip from the spout after the tap has been turned off
- A handle that feels stiff or no longer moves as smoothly as it once did
- Water flow or temperature that’s inconsistent or difficult to control
- A mixer tap that doesn’t shut off completely, even when the handle is fully closed
Even then, replacing the cartridge only works if the correct replacement is used. Many cartridges look almost identical but differ slightly in size, locating pins, or internal design. Installing the wrong one can leave the tap leaking, create a loose handle or lead to another repair sooner than expected.
When the Issue Is the Tap Body or Flexible Hoses
If the tap body is cracked or corroded in several places, replacing individual parts may not be the most practical solution. Fitting a new mixer tap may provide better long-term value. Expect the plumber to also check under the sink for worn flexible hoses, loose connections, or failing washers, since an unnoticed slow leak can damage cabinetry.
Why Water Pressure Can Cause Repeat Leaks
If cartridges, hoses, and valves keep failing, high water pressure could be a factor. It stresses fittings every time water is used. Not every leak is pressure-related; normal wear is often the only cause. But if problems keep recurring across the property, it’s worth checking the water pressure. A licensed plumber can advise whether pressure control equipment would help protect your fixtures.
Should You Repair or Replace the Mixer Tap?
Many leaking taps can be repaired successfully if the body is still in good condition and the issue is limited to a worn cartridge, seal, or O-ring. This is especially true if the parts are readily available. Other times, replacement may be the answer. The plumber weighs the tap’s condition, part availability, and likely lifespan of a repair before recommending either option.
| Tap repair is usually worth trying when: | Tap replacement is often the better option when: |
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If parts and labour start approaching the cost of a new tap, replacement may save money over time. Ask your plumber to explain their recommendation and provide a clear quote.
Can You Fix a Leaking Mixer Tap Yourself?
If you can safely isolate the water and confidently identify the correct replacement part, replacing the cartridge may be within your capabilities. But even so, DIY isn’t always the best option. It’s often safer to call a plumber, especially if:
- The leak is under the sink.
- The isolation valve won’t shut off properly.
- Fittings have seized.
- The tap is installed through stone or tile.
- There’s visible water damage already.
- The tap still leaks after you’ve replaced the cartridge or attempted a basic repair.
So, What Happens After the Repair?
Once the faulty part is replaced, the plumber runs final checks. These may involve:
- Turning the water supply back on gradually.
- Testing both hot and cold water.
- Checking the spout for drips.
- Inspecting around the base.
- Looking under the sink for leaks.
- Drying the area and retesting shortly after.
The plumber should explain what was replaced and flag any other components showing early signs of wear, so you know what to watch for going forward.
Stop the Leak Before It Spreads With Drain Defenders
A leaking mixer tap can start small but gradually waste water, raise your bills, and let moisture spread into cupboards and benchtops. If you notice a dripping mixer tap, it might be time to seek professional help.
Drain Defenders provides leaking tap repairs across Logan, Brisbane Southside, and surrounding Queensland suburbs. Contact us today, and let our licensed plumbers pinpoint the source and fix your leaking tap properly.