In New Zealand, not all plumbers are authorised to sign off completed work as compliant with the law. A certifying plumber holds a specific licence that allows them to issue a Certificate of Compliance (CoC) — a legal document confirming that plumbing work meets the requirements of the NZ Building Code and the Plumbers, Gasfitters, and Drainlayers Act 2006. Without this certificate, your work may be uninsurable, unsaleable, or even illegal.
The Licensing Tiers Explained
Plumbing in New Zealand is a licensed trade, regulated by the Plumbers, Gasfitters and Drainlayers Board (PGDB). There are several licence classes:
- Tradesperson – Can carry out plumbing work under supervision but cannot certify their own work.
- Journeyman – A historical class; holders can work unsupervised but still cannot certify.
- Certifying Plumber – The highest licence class. Can carry out and certify plumbing work, and can supervise others.
Only a certifying plumber can issue the Certificate of Compliance that is legally required for sanitary plumbing work in New Zealand. This is not optional — it is a requirement under the Plumbers, Gasfitters, and Drainlayers Act 2006.
What Work Requires a Certificate of Compliance?
Any sanitary plumbing work — that is, work on pipes and fittings that carry wastewater, stormwater, or potable (drinking) water inside a building — must be certified. This includes:
- Installing or replacing a toilet, basin, bath, or shower
- Fitting a new hot water cylinder
- Relocating or adding water supply pipes
- Connecting to the wastewater system
- Any work covered by NZ Building Code clauses G12 (Water Supplies) and G13 (Foul Water)
The certifying plumber must inspect the work (whether they did it themselves or supervised someone else doing it) and issue the CoC within a set timeframe after completion.
Why Does It Matter for Homeowners?
This matters for several very practical reasons:
1. Insurance
If uncertified plumbing causes a leak or flood, your home insurer may decline your claim. Always ask for the CoC and keep it with your property records.
2. Selling Your Home
When you sell, a LIM report or due diligence process can reveal uncertified work. Buyers (and their lawyers) will ask questions, and uncertified work can delay or derail a sale.
3. Building Consents
For work that requires a building consent — such as adding a new bathroom or relocating plumbing as part of a renovation — the council will require a CoC from a certifying plumber before issuing a Code Compliance Certificate (CCC). Check with your local council whether your project needs consent; some minor work may fall under Schedule 1 exemptions, but always confirm this before starting.
4. Health and Safety
Poorly installed plumbing can cause contamination of drinking water, sewage leaks, or scalding from incorrectly set hot water systems. The certification process is a safeguard for your household's health. WorkSafe NZ and MBIE Building Performance both emphasise the importance of compliant installations.
What Can a Homeowner Do Themselves?
In New Zealand, sanitary plumbing is restricted work. This means a homeowner cannot legally carry out or certify their own plumbing work on sanitary systems. There are very limited exceptions — for example, replacing tap washers or shower heads is generally considered maintenance and does not require a licence. However, anything involving connections to water supply pipes or the wastewater system must be done by a licensed plumber and certified by a certifying plumber.
If you are unsure whether a job counts as restricted work, contact the PGDB for guidance before starting.
How to Check Your Plumber's Licence
Before hiring anyone, verify their licence on the PGDB's online register at pgdb.co.nz. Search by name or licence number to confirm they hold a current certifying plumber licence. A legitimate certifying plumber will be happy to provide their licence number upfront.
| Licence Class | Can Do the Work? | Can Certify? |
|---|---|---|
| Tradesperson | Yes (supervised) | No |
| Journeyman | Yes (unsupervised) | No |
| Certifying Plumber | Yes | Yes |
When to Call a Professional
Always engage a certifying plumber for any sanitary plumbing work beyond basic maintenance. This includes new installations, alterations, repairs to supply or waste pipes, and hot water cylinder work. Ask them to provide a Certificate of Compliance on completion and keep it safe — it is a valuable document for your property.
You can find qualified, local certifying plumbers in your area through tradedirectory.co.nz.
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