What's different about blocked drains in Christchurch
Seven in ten are private
The city council finds about 70 per cent of lateral blockages in the private stretch, between the household gully trap and the property boundary. That's the section an owner pays to clear.
The council's part has a process
If your drainlayer finds the blockage on the public section, they need evidence of a structural fault before the council will help. Costs come back to you only if footage proves that fault and the council's reviewer agrees.
Three kinds of sewer
Most homes drain by gravity, but parts of the city have pressure or vacuum sewers. Each has its own first call, so it's worth knowing which you're on before something backs up.
One number, any hour
Wastewater spilling in the street, from a manhole, or any urgent sewage problem goes to the council on 03 941 8999, at any time of day.
Which sewer are you on?
| What's yours | Ring first | |
|---|---|---|
| Gravity sewer (most homes) | The lateral on your land, if it serves only your home. Shared laterals are shared. Where a council main crosses your section, the council usually covers about the first metre of lateral too. | A drainlayer, preferably with CCTV, who works out which section is blocked. |
| Pressure sewer | The lateral from the house to the tank. | Ask the council where its responsibility starts, and give the drainlayer that answer. |
| Vacuum sewer | The council checks its vacuum system is working before anyone looks at your pipes. | The council, 03 941 8999. It may then refer you to a drainlayer. |
What you can try, and what to hand over
You can
- Stop running water: no washing machine, dishwasher or showers until it's clear.
- Lift the gully trap grate and look. Water sitting there or spilling over means the blockage is further along the lateral.
- Try a plunger on a single blocked fitting. PGDB lets homeowners clear a blocked drain, as long as they don't alter or repair the inspection pipe or vent pipe.
- Note which fittings are slow and when it started, for the drainlayer.
Leave to an authorised tradie
- Removing traps or opening up the drain.
- Clearing the lateral with a drain machine or water jetter.
- Any repair to a cracked, sagging or root-filled pipe, which is drainlaying.
- Filming the lateral, which you'll need if the council's section is at fault.
Why the footage matters here
Clearing a lateral gets it flowing; it doesn't tell you why it blocked. In Christchurch, the recording also settles the money. The council says the drainlayer determines whether a blockage sits on the private or public section, and its reimbursement depends on visual proof of a structural fault on its side. So ask before work starts whether the drainlayer can film the pipe, and that you'll get a copy.
If the footage shows your section is cracked or full of roots, the fix is a repair rather than another clear. Mending a drain with comparable materials, or replacing a length in the same position, needs no building consent when an authorised person does it, but it still has to meet the Building Code. See our Christchurch drainlayers page for repairs.
Questions for a Christchurch drain specialist
- Was the blockage on our section or the council's?
- Can you film the lateral and give us the recording?
- Does the footage show a structural fault, or just a blockage?
- Is our lateral shared with a neighbour?
- Are we on a gravity, pressure or vacuum sewer?
What we would do
If you're in a vacuum sewer area, ring the council before anyone else. Otherwise, book a drainlayer who can bring a camera, and ask for the recording whether the blockage turns out to be yours or not. Most will be on your side of the boundary, so budget for that. If the footage shows a fault on the council's section, send it to the council before paying for more work there.