A leaking drain pipe can cause serious damage to your home's foundations, subfloor, or garden if left unchecked. While a proper repair should always be carried out by a licensed drainlayer, a temporary patch can buy you time and limit further damage until a professional can attend. Here's what you need to know.
First: Identify the Type of Drain
Before you do anything, work out what kind of drain you're dealing with. In NZ homes, you'll typically encounter:
- Stormwater drains – carry rainwater away from the roof and property
- Wastewater (sanitary) drains – carry sewage and greywater from sinks, showers, and toilets
- Sub-soil drainage – manages groundwater around foundations
This matters because wastewater drains are part of your sanitary plumbing system. Under the Plumbers, Gasfitters and Drainlayers Act 2006, any permanent work on sanitary drains must be carried out by a licensed drainlayer. A temporary patch to stop active leaking while you wait for a professional is generally considered acceptable, but you should not attempt a permanent repair yourself.
Safety First
Important: Wastewater leaks can expose you to harmful bacteria and pathogens. Wear waterproof gloves, eye protection, and wash your hands thoroughly after any contact. If the leak involves sewage, ventilate the area well and avoid prolonged exposure. Check WorkSafe NZ guidelines if you're unsure about safe working conditions.
What You'll Need
For a temporary patch, gather the following:
- Waterproof gloves and eye protection
- Clean rags or paper towels
- Pipe repair tape (self-amalgamating silicone tape) or an epoxy pipe repair putty/stick
- A pipe repair clamp (available at Bunnings or Mitre 10)
- Wire brush or coarse sandpaper
- Clean water and a cloth
| Product Type | Best For | Approx. Cost (Guide Only) |
|---|---|---|
| Self-amalgamating tape | Small cracks, pinhole leaks | $10–$25 per roll |
| Epoxy repair putty/stick | Larger cracks, joints | $15–$35 |
| Pipe repair clamp | Split pipes, burst sections | $20–$60 |
Prices are a rough guide only and will vary by retailer and product.
Step-by-Step: Applying a Temporary Patch
1. Stop or Reduce Water Flow
If possible, reduce water use in the house to slow the leak. For stormwater drains, wait for rain to ease if safe to do so.
2. Clean and Dry the Area
Use a wire brush or coarse sandpaper to remove dirt, rust, or loose material around the leak. Wipe the area as dry as you can with a clean cloth. Most repair products bond better to a clean, dry surface — though some epoxy putties are designed to work on damp pipes.
3. Apply Your Chosen Repair Product
Self-amalgamating tape: Start wrapping 5–10 cm back from the leak, stretching the tape firmly as you go and overlapping each layer by about half. Continue 5–10 cm past the leak. The tape fuses to itself to create a watertight seal.
Epoxy repair putty: Knead the two-part putty together until it's a uniform colour, then press it firmly over the crack or hole, smoothing the edges. Allow it to cure as per the manufacturer's instructions before restoring flow — typically 10–60 minutes.
Pipe repair clamp: Centre the rubber gasket over the leak, place the clamp around the pipe, and tighten the bolts evenly until snug. Don't overtighten on plastic pipe as this can cause further cracking.
4. Monitor the Repair
Once applied, watch the patch closely for the first hour. A temporary repair is not a permanent fix — it may hold for days or weeks, but it will eventually fail. Arrange for a licensed drainlayer to carry out a proper repair as soon as possible.
What You Should NOT Do
- Do not use standard duct tape or plumber's thread tape as a pipe patch — they are not designed for this and will fail quickly
- Do not attempt to permanently repair or replace sanitary drain pipes yourself — this is restricted work under NZ law
- Do not ignore a sewage leak, even a small one; it poses a health risk and may breach the NZ Building Code requirements around sanitary drainage (Clause G13)
- Do not cover up a leak inside a wall or under a slab without professional assessment
Common Causes of Leaking Drain Pipes
- Tree root intrusion (very common in NZ with large native and exotic trees)
- Ground movement or subsidence
- Corrosion in older cast iron or clay pipes
- Joint failure or poor original installation
- Physical damage from digging or heavy vehicles
Understanding the cause helps your drainlayer choose the right permanent solution, which may include pipe relining, excavation and replacement, or joint repair.
When to Call a Professional
Call a licensed drainlayer immediately if:
- The leak involves sewage or wastewater
- The pipe has burst or collapsed
- You notice foul odours, soggy ground, or sinkholes near drains
- The leak is inside a wall, under a concrete slab, or otherwise inaccessible
- Your temporary patch isn't holding
All permanent drain repairs on sanitary systems must be done by a professional registered with the Plumbers, Gasfitters and Drainlayers Board (PGDB). You can find qualified, local drainlayers on tradedirectory.co.nz.
For stormwater drains, the rules are slightly different, but it's still worth getting a professional assessment — especially if the issue is recurring or the pipe is underground. Check with your local council about any consent requirements, as some drainage work may need a building consent even if it appears minor.