In New Zealand, not all licensed plumbers hold the same level of authorisation. The key difference comes down to who can legally certify completed plumbing work — and getting this wrong can have real consequences for your home's compliance, insurance, and resale value.
The Licensing Framework in New Zealand
Plumbing, gasfitting, and drainlaying in New Zealand is regulated under the Plumbers, Gasfitters, and Drainlayers Act 2006. The Plumbers, Gasfitters and Drainlayers Board (PGDB) is the body responsible for licensing and overseeing practitioners. There are several licence classes, but for plumbing the two you'll most commonly encounter are:
- Registered Plumber
- Certifying Plumber
What Is a Registered Plumber?
A registered plumber has completed their trade training and passed the required assessments to be registered with the PGDB. They are fully qualified to carry out sanitary plumbing work — this includes installing, maintaining, and repairing pipes, fixtures, and fittings that deal with water supply and waste in your home.
Registered plumbers can legally perform the hands-on work, but they cannot issue a Certificate of Compliance (CoC) for that work themselves. Instead, their work must be checked and certified by a certifying plumber.
What Is a Certifying Plumber?
A certifying plumber holds a higher level of authorisation. They have demonstrated additional competency and experience beyond registration, and are authorised by the PGDB to:
- Supervise registered plumbers and trainees
- Inspect completed plumbing work
- Issue a Certificate of Compliance (CoC) confirming the work meets the requirements of the NZ Building Code and relevant standards
The CoC is a legal document. For most sanitary plumbing work, a CoC must be issued by a certifying plumber and provided to the homeowner within 20 working days of the work being completed. You should keep this document safe — you may need it when selling your home or making an insurance claim.
Why Does This Distinction Matter?
The certification requirement exists to protect homeowners. Plumbing that isn't compliant with the Building Code can cause serious problems — from water damage and leaks to health risks from contaminated water or inadequate drainage. The Building Code clauses most relevant to plumbing include G12 (Water Supplies) and G13 (Foul Water).
If a plumber carries out work without the correct certification being issued, you as the homeowner could face:
- Difficulty obtaining building consent sign-off
- Issues with your home insurance
- Complications when selling your property
- Potential liability for non-compliant work
BRANZ and MBIE Building Performance both provide guidance on compliance requirements for building and plumbing work in NZ.
A Quick Comparison
| Feature | Registered Plumber | Certifying Plumber |
|---|---|---|
| Can perform sanitary plumbing work | ✅ Yes | ✅ Yes |
| Can supervise trainees | Limited | ✅ Yes |
| Can issue Certificate of Compliance | ❌ No | ✅ Yes |
| Higher level of assessed competency | ❌ | ✅ Yes |
What About Trainees and Craftsmen?
The PGDB also registers trainees (working toward registration) and previously issued tradesman licences (an older category). Trainees must work under supervision and cannot certify work. If you're unsure about a plumber's licence status, you can search the public register on the PGDB website.
What Can a Homeowner Do Themselves?
Some very minor plumbing tasks are not restricted work and can be done by a competent homeowner — for example, replacing a tap washer or a showerhead on an existing fitting. However, any work that involves connecting to or modifying the sanitary plumbing system (pipes, drains, water supply connections) is restricted work under NZ law and must be carried out by a licensed plumber. Attempting restricted work yourself is illegal and could void your home insurance.
If you're a tenant, your landlord also has obligations under the Healthy Homes Standards to maintain plumbing in good working order.
When to Call a Professional
For any plumbing work beyond the most basic maintenance, you should hire a licensed plumber. For work that requires a Certificate of Compliance — such as installing a new bathroom, relocating pipes, or connecting a new hot water cylinder — make sure you engage a certifying plumber, or confirm that the company you hire has a certifying plumber on staff who will sign off the work.
Always ask your plumber:
- Are you registered or certifying with the PGDB?
- Will I receive a Certificate of Compliance on completion?
You can find qualified, local plumbers on tradedirectory.co.nz and verify their licence status directly with the PGDB.
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