In most cases, yes — you can connect a new laundry to an existing drain in NZ, but the work must be carried out (or supervised) by a licensed tradesperson. Drainlaying and plumbing connections are restricted work under NZ law, meaning a homeowner cannot legally do this themselves unless they are licensed. Here's a practical breakdown of what's involved, what consents you may need, and how to get it done safely and legally.
Is This Restricted Work?
Yes. Under the Plumbers, Gasfitters and Drainlayers Act 2006, connecting any new fixture — including a laundry tub, washing machine waste outlet, or floor waste — to your home's drainage system is restricted drainlaying and plumbing work. This must be carried out by, or under the direct supervision of, a person registered and licensed with the Plumbers, Gasfitters and Drainlayers Board (PGDB).
As a homeowner, you are not permitted to make these connections yourself, even on your own property. Doing so is illegal and could void your home insurance, create liability issues, and result in fines.
Safety note: Incorrectly connected drains can cause wastewater backflow, foul odours, and health hazards. Always use a licensed professional.
Do You Need a Building Consent?
This depends on the scope of work. Under the Building Act 2004 and its Schedule 1 exemptions, some minor plumbing work may not require a building consent — but the rules are nuanced.
- If you are adding a new laundry room or converting a space (e.g., a garage or spare room), this is likely to require a building consent, as it involves a change of use or new sanitary fixtures.
- If you are simply replacing or relocating a laundry within an existing laundry space with minimal structural change, it may fall under a Schedule 1 exemption.
- Any work must still comply with NZ Building Code clauses G12 (Water Supplies) and G13 (Foul Water), which govern how sanitary plumbing and drainage must be designed and installed.
Always check with your local council before starting work. What qualifies as exempt varies by council and by the specifics of your project. You can find general guidance at MBIE Building Performance.
What Does the Work Actually Involve?
Connecting a new laundry to an existing drain typically involves:
- Locating the existing drain — your licensed drainlayer will identify the nearest suitable drain (usually a soil stack, branch drain, or gully trap) to connect to.
- Checking drain capacity — the existing drain must be able to handle the additional wastewater load from a washing machine (which can discharge 50–100 litres per cycle) and a laundry tub.
- Installing a trap — all fixtures must have a P-trap or S-trap to prevent sewer gases entering the home, as required by NZ Building Code clause G13.
- Venting — proper venting of the new branch drain is essential to maintain water seals in traps and prevent gurgling or backflow.
- Connecting to the drain — this may involve cutting into an existing PVC drain pipe and installing a saddle junction or tee fitting.
- Waterproofing the laundry floor — if a floor waste is installed, the floor may need to be waterproofed to comply with Building Code clause E3 (Internal Moisture).
Typical Steps in the Process
| Step | Who Does It | Notes |
|---|---|---|
| Check consent requirements | Homeowner + council | Confirm before any work starts |
| Engage a licensed drainlayer/plumber | Homeowner | Find one on tradedirectory.co.nz |
| Design and plan the connection | Licensed tradesperson | Must meet NZS 3604 and Building Code |
| Carry out drainlaying work | Licensed drainlayer | Restricted work — not DIY |
| Inspection (if consented) | Council building inspector | Required for consented work |
| Code Compliance Certificate (CCC) | Council | Issued after successful inspection |
What Can a Homeowner Do?
While the drain connection itself is restricted, there are tasks you can legally do yourself to prepare:
- Clearing the area and making the work site accessible
- Painting or finishing the laundry room walls (check out Resene for moisture-resistant paint options)
- Installing laundry cabinetry (non-structural)
- Purchasing fixtures such as a laundry tub — available at Bunnings or Mitre 10
- Connecting a washing machine to an already-installed and compliant standpipe/waste outlet (this is generally not restricted work once the plumbing is in place)
Healthy Homes and Rental Properties
If you are a landlord adding a laundry to a rental property, be aware that Healthy Homes Standards set requirements for moisture and drainage in rental homes. A properly drained and ventilated laundry space can contribute to compliance. Ensure all work is consented and certified where required.
When to Call a Professional
You should engage a licensed drainlayer or registered plumber for this project from the outset. They can:
- Advise whether a building consent is needed
- Design a compliant drainage layout
- Carry out all restricted work legally
- Arrange inspections and help obtain a Code Compliance Certificate
You can find qualified, local drainlayers and plumbers on tradedirectory.co.nz. Always ask to see their PGDB licence before work begins — you can verify a tradesperson's licence at pgdb.co.nz.