A proper invoice from a plumber isn't just a bill — it's a legal document that protects both you and the tradesperson. In New Zealand, there are specific details a plumber's invoice should include to comply with tax law, consumer rights, and the licensing requirements set by the Plumbers, Gasfitters and Drainlayers Board (PGDB). Knowing what to look for helps you confirm you've hired a legitimate professional and gives you a clear record if anything needs to be followed up later.
The Plumber's Business and Licence Details
Every invoice should clearly identify who did the work. Look for:
- Full business name (or sole trader name) and trading name if different
- Physical or postal address and contact phone number or email
- PGDB licence number — this is one of the most important things to check. Plumbing, gasfitting, and drainlaying are restricted trades in NZ, meaning the work must be carried out or supervised by a licensed practitioner. You can verify a licence at the Plumbers Gasfitters & Drainlayers Board website.
- GST registration number (if the business is GST-registered, which most trading plumbers will be)
If a tradesperson can't provide a PGDB licence number, that's a serious red flag.
Invoice Number and Date
Every invoice should have:
- A unique invoice number for record-keeping
- The date the invoice was issued
- The date(s) the work was carried out (if different from the invoice date)
These details matter for warranty purposes, insurance claims, and any future building consent documentation.
Your Details as the Customer
The invoice should be addressed to you, including:
- Your full name (or business name if applicable)
- The address where the work was carried out
- Your contact details if relevant
A Clear Description of the Work Done
This is where many invoices fall short. A good plumber's invoice should describe the work in enough detail that you understand exactly what was done. This includes:
- The type of work (e.g., replacing a hot water cylinder, installing a new toilet suite, clearing a blocked drain)
- Location within the property (e.g., main bathroom, kitchen, under-floor)
- Any compliance work completed, such as work carried out under the NZ Building Code (particularly clauses G12 for water supply and G13 for foul water)
- Whether a building consent was required and obtained, or whether the work falls under a Schedule 1 exemption — always confirm consent requirements with your local council
Itemised Labour and Materials
A transparent invoice separates out costs so you can see what you're paying for:
| Line Item | Example |
|---|---|
| Labour (hours × hourly rate) | 2.5 hrs @ $120/hr = $300 |
| Materials (itemised) | Pressure-limiting valve, copper fittings |
| Call-out or travel fee | If applicable |
| Subcontractor costs | If another trade was involved |
| Subtotal (excl. GST) | $XXX |
| GST (15%) | $XXX |
| Total (incl. GST) | $XXX |
As a rough guide, plumbing labour rates in NZ vary by region and job type — always get a quote upfront and compare it to the final invoice.
GST Requirements
If the plumber is GST-registered (turnover over $60,000/year), they must issue a tax invoice for any supply over $50. This tax invoice must show:
- The words "Tax Invoice"
- Their GST number
- The GST amount charged (or a statement that GST is included)
- The total amount payable
This is required under the Goods and Services Tax Act 1985. If you're a business owner, you'll need this to claim GST back.
Compliance Certificates and Producer Statements
For certain plumbing work — particularly anything involving new installations, alterations, or work requiring building consent — the plumber may need to provide:
- A Certificate of Compliance confirming the work meets the NZ Building Code
- A Producer Statement (PS3) if they're supervising licensed building work
Check with MBIE Building Performance or your local council if you're unsure whether your job required consent and what documentation you should receive.
Payment Terms
The invoice should clearly state:
- Payment due date (e.g., 7 days, 20th of the following month)
- Accepted payment methods (bank transfer, credit card, etc.)
- Bank account details if paying by direct credit
- Any late payment terms if applicable
Warranty Information
A reputable plumber will note any warranty on workmanship (commonly 12 months) and reference any manufacturer warranties on parts or fixtures installed. Keep this invoice somewhere safe — you'll need it if something goes wrong.
When to Call a Professional
All plumbing, gasfitting, and drainlaying work in NZ is restricted work under the Plumbers, Gasfitters, and Drainlayers Act 2006. This means it must be performed by — or under the direct supervision of — a licensed practitioner. Homeowners can do very minor maintenance (like replacing a tap washer in some cases), but anything involving pipework, drainage, hot water systems, or gas connections must be handled by a licensed professional.
If you receive an invoice that's missing key details like a PGDB number or GST information, contact the Plumbers Gasfitters & Drainlayers Board for guidance. For consumer disputes, Consumer NZ is a helpful resource.
Need a trustworthy, licensed plumber? Search for qualified local plumbers on tradedirectory.co.nz to find professionals who stand behind their work and their paperwork.
Sources & Further Reading
- Plumbers Gasfitters & Drainlayers Board — Licence verification
- MBIE Building Performance — Building consent information
- Licensed Building Practitioners — Restricted building work
- Consumer NZ — Your rights with tradespeople
- WorkSafe NZ — Health and safety on the job
- BRANZ — NZ building and construction guidance
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