A properly connected downpipe is one of the most important parts of your home's weathertightness system. If rainwater isn't being directed away from your foundations correctly, you risk water damage, dampness, and even structural problems over time. The good news is that a basic check is something most homeowners can do themselves with a little know-how.
Why a Good Downpipe Connection Matters
In New Zealand, stormwater management is covered under Clause E1 (Surface Water) of the NZ Building Code, which requires that surface water — including roof runoff — is disposed of in a way that doesn't damage your property or neighbouring properties. A failed or disconnected downpipe connection can undermine this, leading to:
- Saturated soil around foundations, causing subsidence or dampness
- Subfloor moisture problems, especially in older homes with timber piles
- Erosion of garden beds or driveways
- Potential issues with your obligations under the Healthy Homes standards if you're a landlord
What You'll Need
- A garden hose
- A torch
- A flat-head screwdriver or small mirror (optional)
- Safety glasses if you're poking around debris
- Rubber gloves
Step-by-Step: How to Check Your Downpipe Connection
1. Start at the Top — Inspect the Downpipe Itself
Begin by visually checking the downpipe from top to bottom. Look for:
- Cracks, splits, or holes in the pipe (common in older uPVC or cast iron pipes)
- Loose or missing brackets that allow the pipe to pull away from the wall
- Gaps at joints where sections of pipe connect
- Rust stains or water marks on the wall below a joint, which suggest a leak
2. Check the Shoe and Entry Point
The shoe is the curved fitting at the bottom of the downpipe that directs water into the drain. Check that:
- The shoe is firmly attached and pointing into the drain inlet, not just resting near it
- There's no visible gap between the shoe outlet and the drain grate or pipe entry
- The drain inlet isn't blocked with leaves, silt, or debris
3. Run a Hose Test
This is the most reliable DIY check. Have someone run a garden hose at full pressure into the top of the downpipe (or into the gutter above it) while you watch the drain entry point at the bottom:
- Water should flow smoothly and quickly into the drain with no backing up
- If water pools around the base of the downpipe or spills out sideways, the connection is likely blocked, broken, or missing altogether
- If water gurgles and rises slowly, there may be a blockage further down the drain line
4. Check for Discharge to the Right Place
In most NZ councils, downpipes must connect to the stormwater drain, not the wastewater (sewage) drain. Cross-connections are a serious issue and may be illegal under your local council's bylaws. If you're unsure which drain your downpipe connects to, contact your local council — they can often advise or inspect.
Note: Some older homes, particularly pre-1990s, may have downpipes discharging to a soakpit or directly to ground. Whether this is acceptable depends on your council and site conditions. Check with your local council before assuming it's compliant.
5. Inspect Underground if Accessible
If you have a visible drain inspection point (a small round lid near the base of the downpipe), remove it carefully and shine a torch inside. Look for:
- Root intrusion from nearby trees
- Collapsed or cracked pipe (visible as misaligned sections or soil ingress)
- Standing water that suggests a blockage downstream
For a more thorough underground check, a licensed drainlayer can carry out a CCTV drain inspection — well worth it if you suspect a serious problem.
Common Problems and What They Mean
| Problem | Likely Cause | Action |
|---|---|---|
| Water pooling at base of downpipe | Disconnected shoe or blocked drain | Clear blockage or reconnect shoe |
| Damp patch on wall below a joint | Leaking pipe joint | Re-seal or replace joint |
| Slow drainage during heavy rain | Partial blockage or undersized drain | Flush drain; call a drainlayer if persistent |
| Water discharging to wrong drain | Cross-connection | Call a licensed drainlayer |
| Gurgling from drain | Partial blockage or venting issue | Flush and monitor; call a drainlayer if ongoing |
Simple Fixes You Can Do Yourself
- Clearing a blocked drain inlet: Remove the grate and clear out leaves and silt by hand or with a hose. Wear gloves.
- Re-securing a loose shoe: Use appropriate pipe clips and stainless steel screws to reattach the shoe to the wall and ensure it seats properly over the drain inlet.
- Sealing a leaking joint: Clean the joint thoroughly and apply a compatible sealant. Check with your local plumbing supplier or Sika for a suitable product for your pipe material.
When to Call a Professional
Some issues go beyond a DIY fix. Call a licensed drainlayer (registered with the Plumbers, Gasfitters and Drainlayers Board) if you find:
- Evidence of a collapsed or cracked underground drain
- A suspected cross-connection between stormwater and wastewater
- Persistent flooding around foundations despite clearing visible blockages
- Any work that requires breaking ground to access or repair underground pipework — this is restricted work under the Plumbers, Gasfitters and Drainlayers Act 2006 and must be carried out by a licensed professional
A qualified roofer can also help if the problem originates higher up — for example, a poorly positioned downpipe outlet or a gutter that's directing water to the wrong location. You can find licensed local roofers and drainlayers on tradedirectory.co.nz.
Safety note: When working at height to inspect gutters or the top of downpipes, always use a stable ladder with someone to foot it, and never lean out beyond arm's reach. For roofs, consider leaving any height work to a professional.
Roofing Association of NZ (RANZ)
Licensed Building Practitioner (LBP)
.png)
