At least one break in Wellington's pipe network daily

In his second week, Wellington Water's new chief executive says fixing recurring leaks is not a good use of money, with at least a break per day in the pipe network since he started.

On Friday morning, a meeting of the Wellington Water committee, which includes the region's four mayors, heard thousands of leaks have been fixed so far this year.

But new chief executive Pat Dougherty, who replaced Tonia Haskell on 18 September, told the committee there was one street in which the drinking water pipe had been patched five times in six days.

He said it was not a good use of money, and he was worried about the lack of drought security, especially approaching summer.

Wellington Water has been the subject of two scathing reviews in four years and has been criticised for poor performance, a lack of accountability, and a dysfunctional culture.

Most recently, an independent report in July revealed Wellington Water staff took four months to tell the region's councils about an error in budgeting advice, which left them with a bill of $51 million over three years.

Board chair Nick Leggett said the forecasted cost turned out to be wrong too, so the gap was actually $40.5m.

Although "not an excuse" old and borrowed IT systems had contributed to the error, he said.

The report compared the accounting mistake to the fluoride scandal when a review found fluoridating water was "not a priority" and there were no plans to reinstate fluoride in two water stations as it wasn't clear who was accountable for fixing the issue.

Leggett told the meeting that significant progress on fixing leaks, along with behaviour change among residents, meant about four million litres were being saved per day across the region.

They were on track to renew 9.1 kilometres of pipe this year, on top of 24km last year - but he said the recommendation was 100km per year, just to keep on top of things.

Cultural challenges identified by the review were being addressed and Leggett said he expected the committee to hold the entity accountable for improvement.

Despite the progress, Dougherty said they needed new IT systems and more bodies on the ground, or the network would face a "serious risk of failure".