Auckland sewer sinkhole: Watercare pushes repair timeframe out by months, 25m section of pipe blocked

Over 25 metres of an Auckland sewer line is blocked, requiring “major” excavation to unclog the pipe, but authorities say overflowing wastewater will make swimming in the harbour unsafe for the next 10 days.

New photographs from inside the brick pipe show the extent of the blockage. Watercare workers last night removed about three tonnes.

Watercare earlier said it could take at least three days to unblock the damaged central Auckland sewer pipe, with millions more litres of wastewater potentially flowing into the Waitematā Harbour.

However, Watercare’s chief operating officer Mark Bourne now says clearing the blockage “could take several weeks and the pipe’s long-term repair is likely several months away”.

Auckland Deputy Mayor Desley Simpson, meanwhile, said a “short, sharp” bout of rain today could “sadly result in further [sewage] overflows” due to the blocked pipe.

New photograph from inside blocked sewer line beneath St George's Bay Rd in Parnell. Photo / Watercare

Bourne told TV3′s AM that he is aware of three locations where wastewater is flowing into the Waitematā.

“There are two locations near Mechanics Bay that commenced yesterday afternoon, and yesterday evening we monitored a third location towards the western end of the Viaduct Harbour,” Bourne said.

To keep sewage moving around the blockage, it will be pumped from one manhole to another - “a massive undertaking, likely to be the largest wastewater bypass solution in New Zealand ever”.

“Our crews have been working around the clock to try to clear as much of the blockage as possible. Last night, by hydro-excavation - jetting water into the blockage - we were able to clear about three tonnes of material.

“But with a 25-metre section of debris, it’s looking very unlikely that we’ll be able to clear the full blockage without major excavation.”

Simpson called the situation “a massive problem needing an enormously detailed solution. This is not an easy fix”.

The sinkhole on St George's Bay Rd is the size of a tennis court.

The main Auckland sewer line collapsed, causing a massive tomo (sinkhole) to open up, with wastewater overflow pouring into the harbour and closing 25 city beaches on all sides of the harbour.

The 13m-deep hole descends to a 2.1m-wide collapsed brick pipe below a private property on St Georges Bay Rd in Parnell that serves central Auckland and West Auckland.

Bourne said crews have been working overnight to unblock the pipeline.

“Once the pipeline is unblocked and it can return to service and that will prevent the overflows from returning.

“Then we can get on with the repair ourselves.”

Bourne classified the quantity as “a large overflow”.

The sinkhole at St Georges Bay Rd in Parnell.

As much as hundreds of litres per second of wastewater was spilling into the harbour.

“That’s why we’re asking people not to swim, fish, or do watersports in the Waitematā Harbour, as all of the beaches have been black-flagged,” Bourne said.

A rāhui (temporary ban) has been placed on the harbour by local iwi Ngāti Whātua Ōrākei.

This morning, Act Party leader and Epsom MP David Seymour said Auckland clearly has an infrastructure problem.

“We have been saying that we should be sharing GST on construction, shouldn’t be doing haphazard intensification as proposed by Labour and National, and we need to find new ways to fund infrastructure,” he said, standing next to the growing sinkhole.

Seymour said developers should have the tools to ensure that when development happens, it pays for itself and the infrastructure keeps up with the development.

Auckland Deputy mayor Desley Simpson told TVNZ’s built, not enough infrastructure, that leads to a massive hole where a 113-year-old brick sewer has collapsed,” he said.D

Parnell Business Association general manager Cheryl Adamson said the collapsed pipe “comes as no surprise”, saying overflowing sewage has plagued properties for years.

“Watercare’s inability to address a number of issues our businesses have had, some dating back to 2021, has us all very concerned.

“Business owners have suffered enough. Businesses in Watt St had sewage water into their premises earlier this year. Along The Strand, certain businesses who have relocated back after the January floods complain about unpleasant smells in their bathrooms after heavy downpours.

“We’ve been calling on a resolution for a long time, with this collapsed pipe being one of many signs that the water infrastructure systems in Parnell are in dire need of support.”

Safeswim’s website shows all beaches west of St Heliers and several on the North Shore in Auckland are closed. Photo / Safeswim

Bourne said they will be taking water quality samples during the overflow, and once it stops. “Typically, it is safe to swim from between 48-72 hours after an overflow is stopped.”

Auckland deputy Mayor Simpson told TVNZ’s Breakfast this morning the council was working round the clock to fix the sinkhole.

Crews had been working through the night, pushing “a huge amount of water” through to clear the blockage.

“They’re going manhole by manhole to try and clear it,” Simpson said.