A third of Wellington's wastewater pipes are either in poor or very poor condition, making them in the worst state of the largest centres across the country.

But as Finance Minister Grant Robertson points out, the problem of ageing water infrastructure isn't exclusive to the capital, it's something the whole of New Zealand needs to grapple with after decades of under investment.

Two major pipelines have recently failed in Wellington City within a month of one another, which has put the spotlight on problematic ageing pipes hidden beneath the ground.

Absolutely Poositively Wellington

Advertisement

The latest figures compiled by Water New Zealand show 33 per cent of Wellington's wastewater pipes are in poor condition.

These pipes also have the oldest average age, 51, compared with Auckland, Christchurch, Hamilton, Tauranga and Dunedin's. Well-installed pipes should last for at least 100 years.

The figures are based off self reporting by each council's own assessment of their assets.

Just before Christmas a wastewater pipe collapsed in Wellington's CBD, diverting five million litres of wastewater into the harbour before an above-ground bypass could be put in place.

Then in January a wastewater tunnel beneath Mt Albert failed, resulting in more than a million litres of sludge being transported every day by truck in lieu of a pipeline.

Hutt City needs an extra $270m injected into its water infrastructure over the next ten years. Photo / Mark Mitchell.
Hutt City needs an extra $270m injected into its water infrastructure over the next ten years. Photo / Mark Mitchell.

Water New Zealand technical manager Noel Roberts said the poor condition of Wellington's pipes showed there was a need for more investment in wastewater infrastructure.

Wellington also presented particular challenges, he said.

"For instance, there are high costs of maintenance compared to other places because of the geography of the city and high costs of opening up city roading and so on in order to access underground pipes."

Advertisement

The 2016 Kaikoura Earthquake meant the city has been in a discovery and catch up recovery phase in recent years, he said.

Meanwhile, next door in the region, Hutt City councillors have been briefed this week on the woeful state of their water infrastructure.

New mayor Campbell Barry is grappling with the recommendation an extra $270 million needs to be pumped into their pipes, meaning the council would have to double its current budget for capital expenditure.

Budgets on the brink

In 2019, councils across the country spent $1.2 billion in capital expenditure on drinking, waste and stormwater, according to Water New Zealand.

Investment in water infrastructure has always been a challenge because of the competing requirements of councils, Roberts said.

Advertisement

"Much of the network is underground and therefore not visible, so there is a temptation for councils to underspend on buried assets and make more visible changes to cities in order to keep rates low."

A Productivity Commission report into local government funding and financing published late last year relayed concerns about the expanding scope of councils.

Several inquiry participants were worried about increasing council expenditure on "non-core" functions and services as a cost pressure.

In total, councils have allocated $17.2b for water infrastructure spending over the next decade, according to Infometrics.

But $17.2b is almost certainly not enough, as the situation Hutt City Council finds itself in clearly exemplifies.

Finance Minister Grant Robertson says water infrastructure has been under invested in for decades. Photo / Mark Mitchell.
Finance Minister Grant Robertson says water infrastructure has been under invested in for decades. Photo / Mark Mitchell.

Wellington Chamber of Commerce chief executive John Milford said the report into Hutt City's water infrastructure was a wake-up call for elected officials across the region.

Advertisement

"Calling something a 'nice-to-have' doesn't mean it's inherently wasteful. But first, we've got to target investment on the things local government is there to provide.

"We must learn from the recent failures of Wellington City's pipes - this work can't happen soon enough."

Where's the Government?

This week the Government announced details of its $12b cash injection for infrastructure, with roads being the big winner scooping up $5.3b of the $6.8b spend on transport.

Spending on water infrastructure didn't feature.

When Prime Minister Jacinda Ardern was asked about this she said the Government was making "huge progress" on water issues after inheriting the aftermath of the Havelock North water contamination.

Advertisement

The Three Waters Review, commissioned by the Government in mid-2017, includes supporting councils to investigate collaborative approaches to water service delivery, but it's still early days.

"We're not at the stage of funding projects yet and that's why that wasn't part of the infrastructure plan, but we are working closely with local government", Ardern said.

One example of one collaboration in its early stages is in Hawke's Bay. This week the Government announced it would contribute $1.55m towards a review service focused on delivery options for drinking, waste and storm water.

Finance Minister Grant Robertson said water infrastructure was an issue New Zealand needed to grapple with.

"There is no doubt that within our Local Government sector, who are in charge by in large of water, that there has been under investment over many many decades in keeping up with our water infrastructure."