Connecting a new outdoor shower to your existing wastewater drain is absolutely possible — but it's not a straightforward DIY job. In New Zealand, drainlaying work is restricted work under the Plumbers, Gasfitters, and Drainlayers Act 2006, meaning most of the physical drain connection must be carried out (or supervised) by a licensed professional. Here's a practical guide to help you understand the process, your obligations, and what you can reasonably do yourself.
Is This Restricted Work?
Yes — connecting any new fixture to your wastewater drainage system is classified as restricted drainlaying work in New Zealand. Under the Plumbers Gasfitters & Drainlayers Board (PGDB), only a licensed drainlayer (or a licensed plumber with drainlaying scope) may legally carry out or certify this work. This applies to the drain pipework from the shower waste point to where it connects into your existing system.
As a homeowner, you are permitted to do certain preparatory work on your own property — such as digging the trench — but the actual connection to the drain must be done by a licensed tradesperson. If you're unsure where the line is, check with the PGDB or your local council.
Do You Need a Building Consent?
This depends on the scope of your project. Under the Building Act 2004 and its Schedule 1 exemptions, some minor sanitary plumbing and drainage work may not require a building consent — but the rules are specific and can vary by council.
As a general guide:
- A simple outdoor shower with a pre-made, self-contained drainage solution (such as a soak pit or greywater dispersal system, where permitted) may fall under an exemption.
- Connecting to the existing reticulated wastewater system is more likely to require a building consent and compliance with the NZ Building Code, particularly Clause G13 (Foul Water).
- Some councils have additional requirements around outdoor showers near boundaries or waterways.
Always confirm with your local council before starting work. You can find general guidance on consent exemptions at MBIE Building Performance.
Understanding the NZ Building Code Requirements
Your outdoor shower drainage must comply with NZ Building Code Clause G13 (Foul Water), which covers the safe removal of wastewater from sanitary fixtures. Key requirements include:
- Correct pipe grades (typically a minimum fall of 1:60 for 100 mm pipes (confirm the applicable grade with your licensed drainlayer, as requirements can vary)) to ensure self-cleansing flow
- Appropriate pipe materials — uPVC is the most common choice for residential drains in NZ
- Proper trap installation to prevent foul odours and gases entering the shower area
- Adequate ventilation of the drain system
- Protection of the drain from root intrusion and ground movement, particularly important in NZ's varied soil conditions
Your licensed drainlayer will be familiar with these requirements and will ensure the work meets the standard.
What About Greywater and the Environment?
In some rural or lifestyle block situations, homeowners consider directing outdoor shower wastewater to a soak pit or greywater system rather than the reticulated sewer. This can be acceptable in certain circumstances, but:
- You must check with your local council and regional council — discharge to land is regulated under the Resource Management Act (RMA)
- Greywater from showers contains soap, skin cells, and personal care products, so it must be managed carefully to avoid contaminating groundwater or waterways
- Some councils prohibit greywater dispersal entirely in urban areas
For more on water efficiency and greywater, Energywise has useful background information.
Typical Steps in the Process
- Plan your outdoor shower location — consider proximity to the existing drain, slope of the land, and distance from boundaries and waterways.
- Check with your council about consent requirements and any local rules.
- Engage a licensed drainlayer to assess the existing system and design the connection.
- Apply for building consent if required — your drainlayer or a licensed building practitioner can assist.
- Dig the trench (this you can do yourself to save cost, following your drainlayer's instructions on depth and width).
- Licensed drainlayer installs and connects the pipework and arranges any required inspections.
- Backfill and reinstate the trench once the work is signed off.
Materials and Rough Costs
Materials for outdoor shower drainage are widely available at Bunnings, Mitre 10, and PlaceMakers. Common components include uPVC drain pipe (typically 100 mm diameter for a shower), fittings, a P-trap, and inspection openings.
As a rough guide only, labour costs for a licensed drainlayer in NZ can vary significantly depending on your region, the complexity of the connection, and ground conditions. Get at least two or three quotes before proceeding.
When to Call a Professional
You should engage a licensed drainlayer for this project before doing anything else. The drain connection itself is restricted work — doing it yourself or using an unlicensed person is illegal and could result in fines, issues with your home insurance, and problems when you sell the property. A licensed drainlayer will also be able to advise on consent requirements and ensure the work is properly certified.
You can find qualified, local drainlayers and plumbers on tradedirectory.co.nz — look for someone with current PGDB licensing and good local reviews.
Safety note: Working around existing underground services is hazardous. Before any digging, contact Dial Before You Dig (0800 248 344) to locate underground pipes, cables, and other services on your property.
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