In most situations, relocating a downpipe on your home is considered exempt building work under Schedule 1 of the Building Act 2004 — meaning you won't need a building consent. However, the work still needs to comply with the NZ Building Code, and there are specific situations where consent or a licensed professional is required. Here's what every NZ homeowner needs to know before picking up a hacksaw.
What Is a Downpipe and Why Does It Matter?
A downpipe (also called a rainwater leader) carries stormwater from your roof gutters down to either a stormwater drain, a soakage system, or a rainwater tank. Because it's part of your home's stormwater management system, how and where it discharges is regulated under the NZ Building Code — specifically clauses E1 (Surface Water) and E2 (External Moisture).
Getting the discharge point wrong can cause flooding, erosion, moisture damage to foundations, or even create problems for neighbouring properties — so it pays to think it through carefully.
Is Building Consent Required?
Under Schedule 1 of the Building Act 2004, routine maintenance and like-for-like repairs to roof drainage systems are generally exempt from building consent. Relocating a downpipe that remains part of the same drainage system and discharges to the same approved point is typically treated as exempt work — but this is not a blanket rule.
You are more likely to need consent if:
- You are changing where the stormwater discharges (e.g., from a soakage pit to a new drain, or to a new location on the boundary)
- The work involves connecting to the public stormwater network (this may also require approval from your local council or Watercare/Veolia/similar)
- You are altering the drainage system on a multi-unit or commercial property
- The work is part of a larger renovation or re-roofing project that itself requires consent
Always confirm with your local council before starting work. What counts as exempt can vary by council and by the specifics of your property. You can find guidance on Schedule 1 exemptions at MBIE Building Performance.
What Work Can a Homeowner Do Themselves?
Above-ground downpipe work — such as unclipping an existing PVC or pressed-metal downpipe, cutting it to a new length, and re-routing it to the same discharge point — is generally something a competent DIYer can tackle. Common tasks include:
- Repositioning a downpipe along the same wall
- Extending or shortening a downpipe using standard fittings
- Replacing a damaged section with the same material and diameter
- Redirecting a downpipe into an existing rainwater tank
Key materials and fittings are readily available at Bunnings or Mitre 10, including PVC downpipe, offsets, shoes, and brackets in standard NZ sizes (typically 65 mm or 80 mm round, or 75 × 50 mm rectangular).
When Is a Licensed Drainlayer Required?
This is where it gets important. Under the Plumbers, Gasfitters, and Drainlayers Act 2006, certain drainage work is restricted and must be carried out by — or under the supervision of — a registered drainlayer.
You must use a licensed drainlayer if the downpipe relocation involves:
- Connecting to or altering an underground stormwater drain (including private drains on your property)
- Connecting to the public stormwater network
- Installing or modifying a soakage system or sump
- Any work below ground on the drainage system
Check licensing requirements with the Plumbers Gasfitters & Drainlayers Board. Doing restricted drainage work yourself — or hiring an unlicensed person — is illegal and could affect your home insurance.
Practical Steps for Relocating a Downpipe
- Check your discharge point — confirm where your downpipe currently drains and whether the new location will connect to the same point.
- Contact your council — ask whether your specific relocation requires consent or any stormwater approval.
- Plan the fall — downpipes should be as vertical as possible; any offsets should maintain good flow and avoid trapping debris.
- Use compatible materials — match the existing pipe material and diameter. Don't mix metals that could cause galvanic corrosion (e.g., copper and aluminium).
- Seal and flash correctly — where the downpipe meets the fascia or wall, ensure weatherproofing complies with NZ Building Code clause E2.
- Check for underground connections — if you need to alter anything below ground, engage a licensed drainlayer.
Healthy Homes and Rental Properties
If you're a landlord, note that stormwater drainage that causes dampness or moisture ingress can be relevant to the Healthy Homes Standards. Poorly directed downpipes that allow water to pool near foundations can contribute to moisture problems inside the home.
When to Call a Professional
Even if the above-ground work is DIY-friendly, it's worth calling a licensed drainlayer if:
- You're unsure where your underground drains run
- The relocation involves any below-ground connection
- Your property has an older drainage system (clay or concrete pipes) that may need inspection
- You want a producer statement or documentation for your records
You can find qualified, local drainlayers on tradedirectory.co.nz — it's always worth getting a couple of quotes for peace of mind.