Signs the pipe is damaged, not just blocked
- The same drain blocks again within weeks or months of being cleared.
- Roots or fragments of pipe come back on the cutter.
- A sewage smell outside that no overflow explains.
- Sunken, soggy or lush green strips along the line of the drain.
- Camera footage shows cracks, open joints or a dip holding water.
What goes wrong with sewer pipes
Roots work their way into joints and cracks, then grow into mats that snag waste. Ground movement can pull joints apart or crack older pipes, and a sagging length holds water and solids that build up into blockages.
On your side, the system runs from the fixtures, through the gully trap, to the lateral: the pipe joining your drain to the public sewer. Which lengths you have to repair depends on your provider.
Your lateral or the council's?
Whangārei: the district council owns all main sewers, even on private land, and the connection pipe on public land up to the inspection point at the boundary. The owner owns the connection pipe on private land, and repairs and pays for a section that breaks there.
Napier: the city council owns the wastewater pipework up to and including the lateral to the property boundary. Faults inside private property are the owner's to sort out and pay for.
Wellington region: Tiaki Wai says laterals connecting the home to the public network are the owner's to maintain, and that it asks residents to fix faults found in private drains. It adds that local bylaws differ slightly, so check yours.
None of these rules carries over to anywhere else. See who fixes a blocked drain, and your city page, such as Whangārei, Napier or Wellington.
What a drainlayer will do
Find the fault
A drainlayer will clear the line, then run a camera to see the damage and how far it extends.
Mark it above ground
They'll trace the pipe's route and depth, so any digging happens in the right place.
Choose the repair
A short broken section is usually dug out and replaced. A cracked or root-damaged run that still holds its shape may suit relining.
Test and reinstate
They'll test the repaired drain, backfill, put the ground back and hand over the documents for the job.
What changes the job
- Depth: a deeper pipe means more digging and shoring.
- What's above it: lawn is easier than a driveway, slab or established tree.
- How much is damaged: one failed joint, or a whole run.
- The pipe's material and condition either side of the fault.
- Whether the fault is on the provider's side, where its own process applies.
- Whether consent is needed.
What you can do, and what to leave
You can
- Keep a log of each blockage, the date and what was found.
- Ask for footage from every earlier clear or inspection.
- Note trees, paths and paving over the drain line.
- Keep wipes, fat and food scraps out of the drains while you wait.
Leave to an authorised tradie
- Any repair, replacement or relaying of a drain: PGDB lists drain repairs as work homeowners can't do.
- Root cutting and clearing before inspection.
- Reporting a council-side fault to the provider, with the footage.
Consent and sign-off
Repairing a drain with comparable products, or replacing a damaged length with a comparable pipe in the same position, needs no building consent when an authorised person does it, provided the repair meets the Building Code. A new connection to the council's network isn't part of that exemption.
Consented drain work is signed off through council inspections, or by a certifying drainlayer who holds PGDB's self-certification endorsement, an option since the law took effect on 30 June 2026.
Ask to see the drainlayer's current practising licence and check that it covers drainlaying. The drainlayers page explains the licence classes and supervision.
Red flags
- Recommends digging up a whole drain without showing you any footage.
- Says the fault is on the council's side but won't report it or show you why.
- Can't name a certifying supervisor, or the supervisor isn't on the PGDB register.
- Lifts a council manhole lid where the council forbids it, as Napier and Whanganui both do.
What we would do
Don't approve a sewer repair from a description alone. Get the footage, have the drainlayer point to each fault, and find out whether it's your side of the boundary before anything is dug. If the fault turns out to be the provider's, ask the drainlayer to report it at the time and pass on the footage, because that's the evidence the provider will look at.