The national starting point
The Australian Building Codes Board, which runs the WaterMark scheme, puts it plainly for householders: once you have confirmed a product is WaterMark certified, it must be installed by a licensed plumber. Its advice: “Always ask your plumber if they are licensed before they start any work.” It also notes that plumbing work by unlicensed people can attract penalties.
Licensing itself is a state and territory matter. The ABCB describes licensing and enforcement as matters regulated at the jurisdictional level, and keeps a list of the administration to contact in each one.
Three states, side by side
For these three states, the regulator’s own page says enough to set out here. Each row quotes or closely follows that page.
| State | Who may do plumbing work | Small jobs and checking a licence |
|---|---|---|
| New South Wales | Before doing any plumbing, draining or gasfitting work, you need a licence or certificate, regardless of the cost of the work or whether it is residential, commercial or industrial. Unlicensed people, apprentices included, must work under the immediate supervision of a contractor licence or qualified supervisor certificate holder. | Doing unlicensed plumbing, draining or gasfitting work is a breach of the Home Building Act 1989. As at October 2026, the NSW Government lists fines of $22,000 for an individual or $110,000 for a company. |
| Queensland | Only a licensed plumber or drainer may do regulated plumbing and drainage work, and regulated work includes “fixing or replacing toilets, sinks, taps and other fixtures”. Maintaining, repairing, replacing or removing a fitting or fixture is “minor work”: it still needs a licensee, but no local government approval or report to the QBCC. | Unregulated work, which needs no licence, includes replacing a jumper valve or washer in a tap and replacing a domestic water filter cartridge; it must still meet the minimum standards in the legislation and codes. The QBCC’s online registers let you check whether a plumber is licensed. |
| Western Australia | Plumbing work may lawfully be done only by suitably qualified people who hold a plumbers licence from the Plumbers Licensing Board. Licensed plumbing contractors are responsible for the work they perform for six years from completion. | Like-for-like tap repairs and replacements, and like-for-like sanitary fixture repairs and replacements, are examples of minor plumbing work; new and additional sanitary fixtures are major work. Building and Energy offers an online search to check whether a plumber is licensed. |
Reading the three together
As an illustration of how the same job reads in each state, take swapping an old kitchen mixer for a new one in the same spot. In Queensland that is replacing a fitting, which is regulated minor work for a licensee. In Western Australia, a like-for-like tap replacement is listed as minor plumbing work on Building and Energy’s page for licensed plumbers, under the rule that only licence holders may carry out plumbing work. In New South Wales, the licence requirement covers any plumbing work. Changing a washer in the old tap instead would sit on Queensland’s unregulated list. That is this guide’s reading of the pages, not a ruling; the regulator decides.
Where to ask in the other five
For the rest of the country, the ABCB names the administration to contact for the legal requirements in each jurisdiction:
- VictoriaBuilding and Plumbing Commission
- South AustraliaPlumbing enquiries: Energy & Mining (plumbing trades)
- TasmaniaConsumer, Building and Occupational Services
- Australian Capital TerritoryACT Government Planning
- Northern TerritoryBuilding enquiries: Building Advisory Services unit
The same administrations are where the ABCB says to report illegal plumbing activity, or a product that requires WaterMark certification or has been fitted illegally.
Before the plumber arrives
Two things are worth having in hand. The first is a tap that is WaterMark certified, because a licensed plumber is not permitted to install an uncertified product of a listed type. The second, from 1 May 2028 unless your state varies the date, is a tap that carries the Lead Free WaterMark where one is required. Both are explained in the WaterMark guide and the lead-free tapware guide.
If a new tap seems weak once it is in, the WELS scheme lists the usual causes for a licensed plumber to check: debris or blockages in the fitting, pipes that have not been flushed properly, pressure reducing valve settings, and whether the product suits the water pressure at the fitting.
Next tile: Saving water at the kitchen sink
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