Auckland's drinking water pipes are leaking at least 50 million litres a day, far more than Aucklanders have been asked to save during the most severe shortage in decades.
The city's water managers also don't know how much water has leaked over the past five months - a period where usage restrictions came in, and in which there was a huge increase in pipe breakages due to the drying out and contracting of the ground.
However non-profit organisation Water New Zealand said Auckland actually had one of the better rates of 'real water loss' in the country.
To help with theworst water shortage in decades Aucklanders have been asked to save 30 million litres of water a day, by having short showers and reducing the amount of washing they do. Hoses and water blasters connected to town water are off-limits.
But at least one in every eight litres that Auckland produces disappears somewhere along the way - 50 million litres a day down the drain.
Council water body Watercare chief executive Raveen Jaduram admitted it was not even meeting its own target.
"It's not good enough. We're not meeting our [Statement of Intent] target of 13 percent or less, and we're just over that," Jaduram said.
In fact, it has been above 13 percent since the start of 2018.
The last known figure was in January 2020 at 13.4 percent.
Watercare said they did not know the rate since, as it needed physical meter readings, which have not been completed since the Covid-19 lockdown was lifted.
Pipes leaking for weeks - Auckland resident
Torbay resident Lynda Breeze is concerned about how careful Watercare has been in protecting the city's scarce supply.
She said there had been leaks near her house which took weeks to fix.
One was during the height of summer when there were hundreds of extra leaks due to the dry weather cracking pipes.
"[It was] quite a lot of water. I went and filled my bucket up, I think I estimated one minute to fill a 10-litre bucket. And that wasn't all of it [being collected]," Breeze said.
Ten litres a minute is 14,000 litres a day, for three weeks - a lot of short showers. She and her neighbours were calling Watercare to get it fixed, but they had given up by the time it was actually done three weeks later.
Breeze said the length of time it took to fix was frustrating and knew it was not just her street. Others leaks have been more recent.
"One in Browns Bay which I know was a bigger one than ours. My husband drove past one in Glenfield a week ago and someone there said it had been going for two weeks," Breeze said.
"It's really frustrating me that at a time Watercare are talking about conserving water and that we're in a drought, it's frustrating that water's just going down the drain."
Auckland's piped water network is vast. Jaduram and board chair Margaret Devlin said some amount of leakage was inevitable; it was more a question of what level of could be accepted or was economical.
In addition, leak detection can be hard and expensive. Contractors can't see through the ground to know where the pipe is broken, and sometimes the underground plans do not line up with where pipes actually run.
'We should have woken up' - Auckland councillor
Jaduram said they had started a proactive leak detection programme.
Over the next year council will examine 6000km of pipes, and an improved response time of a maximum of five days.
"So have we put enough resources in? Well, we have now. We've extended it. But there are lots of other challenges in fixing leaks - identifying them is one. We are going to proactively look for leaks as well as [ones the public calls in]," Jaduram said.
Devlin reiterated that it was "an absolute focus of the board to drive leakage down".
The real water loss figure has been above the target of 13 percent for two years.
By Watercare's own standards anything above 13.2 percent is a "serious event" that "needs attention". It's at 13.4 percent as of January 2020, yet it was not mentioned at Watercare's most recent board meeting at the end of June.
Rain has been in short supply for the last 18 months. From January to April this year Auckland received less rainfall than it had ever had since records began.
During restrictions, Watercare's campaign was founded on the line "water is precious".
"It is precious. Absolutely. And we need to do more, I agree," Jaduram said.
Auckland councillor Chris Darby estimated the figure was at least 50 million litres a day, and may even be as high at 70m.
"If you want to put that in perspective, Mayor Goff went to Hamilton and secured an allocation transfer from the Hamilton City Council of 25m litres a day. So the loss through primarily leakage is exactly twice what Mayor Goff secured from Hamilton City Council," Darby said, who is also the chair of the council's planning committee.
Jaduram stated the entire city of Dunedin used 40m litres a day. Auckland's leaking enough to supply the whole city.
Darby was critical of Auckland's preparedness for this shortage.
"We should have woken up. And I say 'we' because ultimately it's the Auckland councillors responsible for the subsidiary of Watercare," said Darby.
Watercare's spending more than $50m to recommission the Hays Creek Dam in Hunua, which will deliver 6m litres a day, as well as bring a former bore back into service which will provide another 5m litres.
'Expensive' to find leaking pipes
Non-profit organisation Water New Zealand data scientist Lesley Smith said Auckland had a lower leakage rate than the rest of the country. For Auckland's 13 percent loss, the rest of the country averages about 18 percent.
She said to find and fix leaking pipes was not easy, and often resource-intensive.
"It's an expensive exercise," Smith said. "Water loss from pipes that are hidden underground are very difficult to identify and very difficult to rehabilitate.
"The options that Auckland's looking at to augment its system - desalination, wastewater recycling - are not cheap either, so reducing water loss needs to be factored in and balanced against those equally expensive technologies."
Smith said there was also an environmental cost tied up in processing water.
"Wastewater and desalination have a big energy penalty, and that comes with a big carbon penalty, and so that feeds into the cycle of climate change, which is in part contributing to some of our water supply issues in the first place. That's another important point to remember when we start thinking through solutions.
"The nice thing about reducing our water loss is that it's an environmental win, whereas wastewater recycling and desalination are a bit of a lose because there's an energy and carbon penalty attached to them."
Jaduram said the older a city was, the more it leaked.
Newer cities, ones that have been rebuilt due to war, or ones that invest heavily have far better leak rates. He promised Watercare would do better.
"There is always more we can do. We are always going to do more as Watercare, because we're asking our consumers to do more and they've been doing well, and our businesses have been doing well. We need to respond as well."