A sanitary plumber is a licensed tradesperson who specialises in the installation, maintenance, and repair of systems that remove wastewater, sewage, and stormwater from buildings. In New Zealand, sanitary plumbing is restricted work under the Plumbers, Gasfitters, and Drainlayers Act 2006, meaning it must be carried out — or supervised — by a person registered and licensed with the Plumbers, Gasfitters and Drainlayers Board (PGDB). Hiring an unlicensed person for this work is illegal and can create serious health and structural risks.
What Does a Sanitary Plumber Actually Do?
Sanitary plumbers work on the sanitary plumbing system — the network of pipes, fittings, and fixtures inside (and immediately outside) a building that carries used water away to the sewer or septic system. This is distinct from the supply of fresh water (which is also plumbing work) and from drainlaying, which covers the underground pipes beyond the building.
Typical work includes:
- Installing and connecting toilets, basins, baths, showers, and laundry tubs
- Fitting kitchen sinks and dishwasher waste connections
- Installing waste pipes, traps, and vents (including the all-important P-traps that stop sewer gases entering your home)
- Connecting hot water cylinders to the waste system
- Installing floor wastes and overflow relief gullies
- Repairing or replacing leaking or blocked waste pipes
- Installing greywater systems where permitted
- Ensuring correct fall and gradient on waste pipes so water drains freely
How Sanitary Plumbing Differs from Other Plumbing Work
It helps to understand the three related — but legally separate — licence categories under the PGDB:
| Licence Type | What They Cover |
|---|---|
| Sanitary plumber | Wastewater pipes and fixtures inside the building |
| Gasfitter | Gas supply pipes and gas appliances |
| Drainlayer | Underground drainage pipes from the building to the sewer or septic tank |
Many tradespeople hold more than one licence — for example, a registered plumber and drainlayer — so they can handle both the internal waste system and the underground drain. Always check which licence your tradesperson holds before they start work.
NZ Building Code and Standards
Sanitary plumbing in New Zealand must comply with the NZ Building Code, particularly:
- Clause G13 (Foul Water) — sets out requirements for the safe removal of sewage and wastewater
- Clause E1 (Surface Water) — relevant where stormwater and sanitary systems interact
- NZS 3500 — the New Zealand Standard for plumbing and drainage, which sanitary plumbers work to
For most sanitary plumbing work inside an existing home (like replacing a toilet or basin), a building consent may not be required under Schedule 1 of the Building Act 2004 — but the work still must be done by a licensed person and a Certificate of Compliance issued. For new installations, additions, or significant alterations, a building consent is usually needed. Always check with your local council before starting, as requirements vary.
You can find guidance on consent requirements at MBIE Building Performance.
What Can a Homeowner Do Themselves?
As a homeowner, you can legally carry out very limited sanitary plumbing work without a licence. Generally, you may:
- Replace a tap washer or O-ring
- Clear a blocked drain using a plunger or drain snake (surface-level blockages)
- Replace a showerhead (if it's a simple unscrew-and-replace job with no pipe alteration)
You cannot legally do your own restricted sanitary plumbing work such as moving waste pipes, installing new fixtures, or altering the drainage layout — even on your own home. The PGDB is clear that restricted work must be performed by a licensed tradesperson.
Safety note: Incorrectly installed waste pipes can allow toxic sewer gases (including hydrogen sulphide) to enter your home, cause structural water damage, and create public health risks. Don't cut corners on sanitary plumbing.
When to Call a Professional
Call a licensed sanitary plumber if you notice any of the following:
- Slow-draining sinks, showers, or basins that don't clear with simple plunging
- Gurgling sounds from drains or toilets (can indicate a venting problem)
- Bad smells coming from drains — a sign a trap may be dry or damaged
- Leaking waste pipes under sinks or behind walls
- You're renovating a bathroom or kitchen and need to move or add fixtures
- You're building a new home or addition and need sanitary plumbing installed
- Your hot water cylinder needs a new waste connection or pressure relief drain
For any of these situations, it's important to use a PGDB-licensed sanitary plumber. You can search for qualified local plumbers on tradedirectory.co.nz to find someone in your area.
What to Expect When You Hire a Sanitary Plumber
- They should be able to show you their current PGDB licence on request
- For consented work, they will issue a Certificate of Compliance (CoC) on completion
- Costs vary depending on the job — as a rough guide, expect a call-out fee plus an hourly rate, with materials on top. Get at least two quotes for larger jobs
- Consumer NZ has useful advice on hiring tradespeople and resolving disputes if things go wrong
Sources & Further Reading
- Plumbers, Gasfitters and Drainlayers Board (PGDB) — licence checks and consumer information
- MBIE Building Performance — building consents, NZ Building Code clauses
- BRANZ — technical guidance on building and plumbing systems
- Standards NZ — NZS 3500 plumbing and drainage standard
- Consumer NZ — advice on hiring tradespeople
- WorkSafe NZ — health and safety obligations on worksites
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