Yes, in most cases a competent DIYer can install or replace a downpipe on a single-storey home in New Zealand. It's not restricted work under the Building Act, so no licence is required — but you do need to follow the NZ Building Code and work safely at height. If the downpipe connects to an underground stormwater drain, that part of the job may involve a licensed drainlayer.
What Is a Downpipe and What Does It Do?
A downpipe (also called a rainwater leader) carries water from your roof gutters down to ground level, where it discharges to a soakage pit, rain garden, or the council stormwater system. A well-functioning downpipe is essential for protecting your home's foundations, cladding, and subfloor from water damage — something the NZ Building Code clause E1 (Surface Water) takes seriously.
Do You Need a Building Consent?
Replacing a like-for-like downpipe in the same location is generally exempt from building consent under Schedule 1 of the Building Act. However, adding a new downpipe in a different location or significantly altering your stormwater drainage layout may require consent. Always check with your local council before starting — rules can vary by region and property type. You can find general guidance on exemptions at MBIE Building Performance.
Tools and Materials You'll Need
Downpipes in NZ are most commonly made from:
- PVC (uPVC) — lightweight, affordable, easy to cut and join; widely available at Bunnings and Mitre 10
- Colorsteel or Zincalume — metal options that match many NZ roofs; available at PlaceMakers
- Copper — premium option, rarely used for new installs due to cost
Common sizes are 80 mm round or 65 × 50 mm rectangular. Match the size and profile to your existing gutters.
Tools you'll need:
- Tape measure and pencil
- Hacksaw or PVC pipe cutter
- Drill and masonry/wood bits
- Spirit level
- Screwdriver or impact driver
- Ladder (rated to your weight plus tools)
- Safety glasses and gloves
Step-by-Step Installation Guide
1. Plan the Route
Mark a straight, vertical path from the gutter outlet down to the discharge point. Avoid windows, doors, and electrical fittings. Aim for a slight fall away from the wall if the pipe runs horizontally at any point.
2. Fit the Gutter Outlet
If you're adding a new outlet to an existing gutter, cut the hole carefully with a hole saw or tin snips. Fit a gutter outlet (also called a drop end) and seal it with a compatible sealant — check the gutter manufacturer's recommendation.
3. Attach Pipe Brackets
Fix pipe clips or brackets to the wall at roughly 1.2–1.5 m intervals (check the manufacturer's spacing guidance). Use appropriate fixings for your wall type — timber framing, masonry, or fibre cement cladding like James Hardie products each need different fixings.
4. Cut and Join the Pipe
Measure and cut sections to length. Use offset bends (also called shoes or elbows) to navigate around eaves or obstacles. For PVC, use solvent cement at joints; for metal, use pop rivets or screws plus sealant.
5. Fit the Shoe at the Bottom
The shoe at the base directs water away from the foundation. It should discharge at least 75 mm above the ground or into a proper drainage inlet.
6. Connect to Stormwater Drainage
If connecting to an underground pipe, this work may be restricted — see below.
Working Safely at Height
Even on a single-storey home, a fall from a ladder can cause serious injury. WorkSafe NZ recommends:
- Use a ladder rated for your weight and set it at the correct angle (1 out for every 4 up)
- Have a second person to foot the ladder
- Never overreach — move the ladder instead
- Wear non-slip footwear
- Avoid working in wet or windy conditions
When to Call a Professional
There are situations where you should bring in a qualified tradesperson:
- Underground stormwater connections — connecting to or modifying an underground drain is restricted drainlaying work under the Plumbers, Gasfitters and Drainlayers Act. This must be done by (or supervised by) a licensed drainlayer registered with the Plumbers Gasfitters & Drainlayers Board.
- Two-storey or complex rooflines — working at greater heights significantly increases risk.
- Asbestos-containing materials — some older NZ homes (pre-1990s) have asbestos in gutters, soffits, or cladding. If in doubt, get an assessment before cutting or drilling anything.
- Consent-required work — if your council determines consent is needed, a Licensed Building Practitioner (LBP) may need to carry out or supervise the work. Check the LBP register.
- You're not confident — there's no shame in calling a professional roofer or plumber. You can find qualified local roofers on tradedirectory.co.nz.
Maintenance Tips
- Clear leaves and debris from gutters and downpipe inlets at least twice a year (more often if you have overhanging trees).
- Check joints and brackets after heavy storms.
- In colder NZ regions, ensure water can drain freely to prevent ice blockages in winter.
Roofing Association of NZ (RANZ)
Licensed Building Practitioner (LBP)
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