How to Fix a Leaking Bathroom Tap — What You Can Do, What Requires a Plumber, and What Happens If You Leave It
That drip is costing you more than it sounds. A tap dripping once per second wastes roughly 20,000 litres a year — enough to fill a small swimming pool, or add a noticeable line item to every quarterly water bill until someone actually does something about it. The sound is the small part. The water going into the cabinet underneath is the part worth worrying about.
Most tap repairs in Australia require a licensed plumber. Not as a conservative interpretation of the rules — as the legal position under plumbing licensing legislation in NSW, ACT, QLD, VIC, and NT. There is a narrow concession for replacing a tap washer on a compression tap. Outside that, unlicensed repair work is a licensing issue, and potentially an insurance issue if something goes wrong.
This page covers what type of tap you have, what is actually causing the drip, the one repair you can legally do yourself, when to call a plumber, and what it typically costs. In that order.
Identify the Tap Before You Diagnose the Fault
The repair pathway is determined entirely by the tap mechanism — and the four common types in Australian bathrooms fail differently, get diagnosed differently, and have different rules about who is permitted to fix them. Getting this wrong before you start, or before you call a plumber, wastes time and call-out fees.
The traditional type — multiple turns to fully open or close. Inside the headgear sits a rubber jumper valve that presses against a machined seat. When the rubber wears it can no longer form a seal. The most common tap type in older Australian homes.
✓ Washer replacement generally permitted in most states — with conditions
Quarter-turn operation. Two ceramic discs control flow by rotating across each other. Fails when a disc is chipped, cracked, or has debris scored across the sealing face. Requires the exact matched disc pair for that specific tap model — not an approximate match.
✗ Not DIY-repairable in most practical or legal circumstances
Single or dual lever. A cartridge controls both temperature and flow volume through one assembly. When it wears or internal seals fail, the tap drips or loses temperature control. Replacement requires the correct cartridge for the specific manufacturer and model.
✗ Licensed plumber work in most states
Single-handle mixer that rotates in multiple directions. Multiple internal components — ball, springs, seat inserts, O-rings. Failure modes vary depending on which component has gone. Not a DIY repair in any practical sense.
✗ Licensed plumber work
The Drip Has a Cause — and the Cause Determines the Fix
Not every drip is a worn washer. There are five distinct failure causes in bathroom taps, each requiring a different repair and different parts. Misdiagnose it and you are paying the plumber to come back. The second call-out fee is the most avoidable cost in this whole exercise.
Worn jumper valve / washer — compression taps only. The rubber jumper valve deteriorates with use — heat, water minerals, and age all degrade it over time. The drip comes from the spout when the tap is fully closed. The most common cause in taps over ten years old, and the one repair that falls within homeowner rights in most states.
O-ring failure — the seals around the spindle or cartridge body wear independently of the washer. When they go, the leak shows up at the base of the tap or around the handle — not at the spout. A different part, a different repair, and in most cases a different licensing position to a simple washer replacement.
Damaged tap seat — the machined surface inside the tap body that the washer presses against. If it is worn, corroded, or pitted, a new washer will not stop the drip — there is nothing for it to seal against. Rectifying the seat requires a tap seat grinder and the experience to use it correctly. In many cases, the tap body needs replacing rather than reseating.
Ceramic disc damage or debris — ceramic disc taps fail when the disc is chipped, cracked, or has fine debris scored across the sealing face. The disc pair must match exactly for that model. Fitting an incorrect replacement disc does not just risk failing to seal — it can crack the opposing disc, converting what was a repair job into a full tap replacement.
Cartridge wear — in mixer taps, the cartridge controls both temperature and volume. When the internal seals wear, the tap drips or temperature regulation becomes unreliable. The cartridge is a model-specific part. Some older or imported brands no longer have cartridges available in Australia, which makes replacement the only viable outcome.
Related: A leaking tap that has been repaired incorrectly often costs more to fix than one that has not been touched. See our full bathroom renovation cost guide ›
What Australian Law Actually Allows You to Do Yourself
Most tap repair work in Australia requires a licensed plumber. Not as a precaution. As a legal requirement under state plumbing licensing legislation. The scope of what a homeowner can do without a licence is narrow, and it is worth being precise about what it actually covers before picking up a spanner.
What is permissible in most states: replacing a tap washer — the rubber jumper valve — on an existing compression tap fitting, where the stop valve isolates correctly and no supply pipework is disconnected or disturbed. That is, in most Australian states, the full scope of the concession. It does not extend to the O-ring, the spindle, the tap body, or anything downstream of the tap itself.
State-by-state position: NSW — under the Home Building Act and NSW plumbing licensing requirements, any work beyond washer replacement requires a licensed plumber. ACT — Access Canberra’s framework permits washer replacement as a homeowner concession; all other tap work requires a licensed plumber. QLD — the QBCC framework includes a washer replacement concession for owner-occupiers. VIC — the VBA position mirrors the national pattern. NT — the NT Building Practitioners Board framework applies the same principle. See our contractor licensing guide ›
What is not permissible regardless of state: replacing a tap body or tapware fitting; connecting or disconnecting supply lines; any work on the isolating valve or pipework upstream of the tap; installing a tap where none previously existed. All of this is licensed plumbing work, regardless of how straightforward it appears, how many instructional videos cover it, or how confident you are in the outcome.
Important: Unlicensed plumbing work that causes or contributes to water damage may void your home and contents insurance. HBCF cover does not apply to DIY work. If there is any doubt about whether the work falls within the washer replacement concession, call a plumber. The call-out fee is considerably less than a declined insurance claim. See our contractor licensing guide ›
Replacing a Tap Washer on a Compression Tap
This section covers the one repair that is generally within homeowner rights in most Australian states — replacing the jumper valve on a compression tap. If the tap is ceramic disc, cartridge, or ball valve, this section does not apply. Stop here and call a plumber.
Tools required
- Adjustable spanner (wrap jaws with cloth to protect chrome)
- Flathead and Phillips screwdrivers
- Replacement jumper valve or washer — 12mm and 15mm are common sizes; remove the old one first to confirm before purchasing
- Torch (for inspecting the tap seat in Step 5)
Isolate the water supply
Turn off the isolating valve under the basin or at the wall. If there is no isolating valve, turn off at the mains. Turn the tap to fully open to release line pressure and confirm the supply is off.
Stop here if: the stop valve does not fully isolate — the drip continues with the valve fully closed. A failed isolating valve is a separate repair requiring a licensed plumber.
Remove the tap handle
Find the decorative button or cap on top of the handle — it prises off with a flathead screwdriver. Remove the retaining screw underneath. Pull the handle straight off, using a gentle rocking motion if it has not been removed before.
Remove the tap bonnet
The bonnet is the collar around the headgear, just below the handle. Use the adjustable spanner to unscrew it anticlockwise. A cloth between the spanner jaws protects the chrome finish.
Remove the headgear assembly
Lift the headgear out of the tap body. The jumper valve sits at the bottom — it may be held by a small brass nut or sit freely. Note how it is seated before removing it.
Inspect the tap seat
Before fitting the new washer, look into the tap body with the torch. Run a fingertip across the seat — the machined ring the washer presses against. It should be smooth.
Stop here if: the seat is pitted, grooved, or feels rough. A new washer will not fix the drip. The seat needs grinding or the tap needs replacing — both require a licensed plumber.
Fit the new jumper valve
Match the size exactly to the original. Seat it in the headgear the same way the old one sat. If it is retained by a small brass nut, hand-tighten only — no tools on the washer nut.
Reassemble
Refit the headgear into the tap body. Screw the bonnet back down firmly but without forcing it. Refit the handle, retaining screw, and decorative cap.
Restore water supply and test
Turn the isolating valve back on slowly. Check for drips at the bonnet and around the handle before opening fully. Run the tap through a full open and close cycle.
Stop here if: the tap still drips after reassembly. The seat is damaged or the tap body is worn. Do not repeat the repair. A seat regrind or full tap replacement is what is needed — both require a licensed plumber.
Have a question about what comes next? If the washer replacement did not resolve it, we can connect you with a vetted licensed plumber. Connect with a specialist ›
When Repair Is the Wrong Answer
Age, parts availability, and the condition of the tap body all affect whether repair is worth attempting. A 25-year-old tap with a scored seat, corroded internals, and a cracked spindle is not a washer replacement job. Replacing the washer extends the life of a tap that is in reasonable condition. It does not restore one that is not.
Repairing ceramic disc and cartridge taps requires the exact replacement disc set or cartridge for that specific manufacturer and model. Many older taps — and most imported taps popular in Australian renovations through the 1990s and 2000s — no longer have parts available locally. Attempting a repair with an approximate match risks cracking the opposing disc or damaging the cartridge seat, converting a repair job into a full tap replacement.
A tap that has been weeping slowly for months has had mineral-laden water sitting against the seat and body threads throughout that period. The body may have softened, the seat become pitted, and the bonnet thread compromised. Replacing the washer might buy another six months. Or it might strip the bonnet thread on reassembly. A realistic assessment of the tap’s overall condition is worth making before committing to repair.
If the tap is over 15 to 20 years old, if the correct parts are no longer available, or if a plumber has assessed the seat as beyond grinding — replacement is the right outcome. Not a failure. Just the honest call at the right stage of the tap’s working life.
Note: Replacing tapware is licensed plumber work in all Australian states. See what bathroom tap replacement typically costs ›
Not Sure What’s Causing the Leak?
Tell us what is happening — the tap type, where the drip is coming from, and how long it has been going. We’ll connect you with a vetted licensed plumber or bathroom renovation specialist in your area.
Lifestyle Bathrooms is a referral and connector service, not a licenced contractor.
What a Licensed Plumber Does — and What It Costs
The figures below are directional industry estimates, not quotes. Scope, the age and type of tap, whether an isolating valve needs replacing at the same time, and whether the call is during business hours all move these numbers significantly.
Some plumbers charge a flat call-out fee plus hourly labour. Others quote a fixed rate per job. Confirm the billing model before work starts — particularly for after-hours calls where the call-out component can exceed the repair cost on a straightforward job.
What a Dripping Tap Actually Costs When You Leave It
Water bill. A tap dripping once per second loses roughly 20,000 litres a year. At current residential water rates across NSW and ACT, that is a material addition to every quarterly bill. Not theoretical. Not a worst-case scenario. It accumulates quietly in the background until someone does the arithmetic or opens the bill.
Cabinet and subfloor damage. A drip at the base of a tap body or from the supply connection under the basin runs directly into the vanity cabinet. Most vanity cabinets are particleboard or MDF — both absorb moisture and do not recover. Once the cabinet floor softens, the subfloor underneath becomes the next surface in the water’s path. By the time swelling or discolouration is visible from outside the cabinet, the structural damage is already well established.
Mould. A persistently damp enclosed cabinet space is a mould-growth environment. Remediation cost for mould in a bathroom cabinet and subfloor is considerably higher than a plumber’s call-out fee would have been at the time the drip was first noticed.
Insurance. Home and contents policies typically require the policyholder to take reasonable action to prevent foreseeable damage. A tap left dripping for weeks or months that has caused water damage to cabinetry or structure is not a sudden and accidental event from an insurer’s perspective. The foreseeable damage argument is one insurers apply regularly, and successfully.
Unlicensed repair and HBCF. If unlicensed work caused or contributed to the water damage — even as a contributing factor — HBCF cover does not apply, and home and contents insurers may use it as grounds to decline the claim. See our insurance protection guide ›
Important: Water damage from a leak that could have been repaired — particularly where unlicensed work was involved — is not reliably covered by insurance. See our insurance protection guide ›
Related: Sustained water ingress at a wall or floor junction can have waterproofing compliance implications under AS 3740. See our waterproofing compliance guide ›
Before You Call — Eight Things Worth Knowing First
A plumber will diagnose on site. But arriving at the call with this information ready shortens the inspection time, helps you assess the quote against what is actually needed, and avoids the situation where the scope being discussed is a surprise.
Tap type identified
Compression, ceramic disc, cartridge, or ball valve. If you cannot tell, photograph the tap and handle — a plumber can often identify the type from a photo before arriving.
Age of the tap
Approximate install date, or whether it is original to the house. Affects the parts availability question and whether repair or replacement is the more sensible call.
Where the drip is coming from
Spout, base of the tap body, around the handle, or under the basin at the supply connection. Each location points to a different cause.
Whether the isolating valve works
Test it: turn the valve under the basin fully clockwise. If the drip stops, it is isolating. If it does not stop, or the valve is seized, mention it when you call — that is additional scope.
Photos taken
Under-basin shots of the supply connection, the tap body from above, and any visible cabinet damage. Speeds up on-site diagnosis.
Whether the tap is under warranty
Standard Australian tapware warranties run five to ten years. If the tap is recent, check the purchase receipt or manufacturer website before agreeing to a chargeable repair.
Whether the drip has recently worsened
A slow drip that has accelerated indicates a component in active deterioration — relevant context for the plumber’s prioritisation.
Whether there is visible cabinet damage
Soft spots, swelling, or discolouration in the vanity cabinet floor indicate the leak has been running longer than the visible drip suggests. This affects the scope of the repair.
Common Questions
Replacing a tap washer on a compression tap is generally within a homeowner’s rights under NSW plumbing licensing law — provided the stop valve isolates correctly and no supply pipework is disturbed. That is the full scope of what the concession covers.
Everything else falls outside it. Replacing the tap body. Connecting or disconnecting supply lines. Working on the isolating valve. Any of those — regardless of how straightforward they appear — requires a licensed plumber in NSW.
The counter-intuitive part: it is not about whether you are capable. The licensing law does not distinguish between competent DIY and incompetent DIY. Unlicensed work on plumbing beyond the washer concession is unlicensed work regardless of the outcome. The consequence is not just regulatory — it is the insurance position if something subsequently goes wrong and a claim is made.
Where the drip is coming from matters as much as the fact that it is dripping.
A drip from the spout when the tap is fully closed is almost always a seal problem — worn washer in a compression tap, or a damaged disc or cartridge in a ceramic or mixer tap. The residual water pressure in the supply line is pushing past a seal that can no longer hold it.
A drip or leak around the base of the tap or around the handle is a different problem — O-ring failure or a loose packing nut. Not the same repair, not the same part, and not the same licensed-plumber-or-not calculation.
A drip from the supply connection under the basin — the flexi hose or the isolating valve — is a third category entirely, and the one most likely to cause cabinet damage because it runs somewhere the homeowner rarely looks.
Knowing which of the three you are dealing with makes the diagnosis faster and the bill lower.
Directional ranges: washer replacement typically runs $120 to $250 including call-out. Cartridge or O-ring replacement $150 to $320. Full tap replacement, supply and install with standard tapware, $350 to $700. After-hours call-out fees run $250 to $500 on top of the labour component.
These are industry estimates, not quotes. The billing model matters — confirm before the plumber starts whether it is a flat job rate or a call-out fee plus hourly. For a straightforward washer job during business hours, the difference is usually small. For an after-hours call on a weekend, it can be the larger part of the total.
It depends on where it is leaking — and the answer is less intuitive than it looks.
The drip from the tap spout into the basin is not the water damage risk. That water goes down the drain. The risk is the drip that nobody notices: the slow seep from the base of the tap body into the vanity cabinet, or the small weep from the flexi hose connection under the basin. That water has nowhere to go except into the cabinet floor and the subfloor beneath it.
Particleboard and MDF — the standard materials in most vanity cabinets — do not dry out and recover once they have absorbed moisture. They swell, soften, and eventually fail structurally. The mould that follows in a persistently damp enclosed space adds remediation cost on top.
The visible drip at the spout is annoying. The invisible drip underneath is the one worth acting on before it becomes a structural repair.
In all Australian states, yes. Replacing a tap involves disconnecting and reconnecting supply lines, which is licensed plumbing work regardless of the state.
The washer replacement concession that exists in NSW, QLD, VIC, ACT, and NT covers the washer inside an existing compression tap fitting. It does not extend to removing the tap from the wall or basin and installing a new one in its place. That is a supply line disconnection and reconnection — licensed work, full stop.
A Leaking Tap Is a Small Problem — Until It Isn’t
The repair window is short. The cost is predictable. A licensed plumber, a call-out, and the right part is a known number with a known outcome. What is not predictable is the cabinet damage, the subfloor remediation, and the insurance conversation that follows a slow leak left unaddressed for six months.
Lifestyle Bathrooms is a referral and connector service, not a licenced contractor. We connect homeowners, investors, and property professionals in NSW, ACT, QLD, VIC and NT with vetted bathroom renovation and plumbing specialists.