Proactive leak detection prevents loss of 5 million litres a day


Sweeping thousands of kilometres of Auckland’s water pipes with an acoustic listening stick to detect invisible leaks has prevented the loss of about 5 million litres of water every day.

Mayor Phil Goff says the leak detection programme is a key part of the effort to minimise water lost to leaks. “Auckland has a lower leakage rate than the rest of the country, but our goal has got to be to do even better and work like this plays a big part in improving the performance of our water network.”

“Our target is to cover 6000 kilometres of pipes by July this year. We’ve already covered 3000km and discovered leaks with an estimated volume of 5 million litres a day. To put it in perspective, that would supply about 30,000 Aucklanders and is the equivalent to what we can produce at our new treatment plant in Pukekohe.”

Acoustic leak detection involves listening for signs of a leak by tapping a stick microphone to a meter or pipe connection. Leaks have a distinctive sound as they are constantly running. The volume of the leak is estimated based on the sound detected – a big leak will be a loud leak.

We are on track to have found and repaired about 9 million litres a day worth of leaks by July this year – with the company saying that’s a conservative estimate.

“This leak detection programme will continue into next year, by which time all of our 9000+ kilometres of pipes would have been surveyed and some will have been swept twice,” Goff says.

Leak detection has been focused on areas with high numbers of reported leaks. The programme is currently underway in Owairaka, Wiri, Pukekohe and Glen Eden.

Our improvement programme manager Anin Nama says the benefits of proactive leak detection are two-fold. “When we find these invisible leaks in our network, we repair them and prevent the associated water loss. But also, by repairing these smaller leaks which are normally invisible on the surface, we prevent larger leaks that can occur when the ground dries up and retracts, causing pipe movement and sometimes breakages.”

The Maungakiekie zone, which includes Mt Wellington and Ellerslie, has seen a significant reduction in the number of reported leaks, which could be partly due to the proactive leak detection work carried out last year. In January 2020 there were 248 reported leaks in the zone, while in January this year there were just 67.

Nama says we have also invested in the reactive side of responding to leaks. “We have 20 per cent more people on the ground fixing leaks this summer, which has allowed us to stay on top of the reported leaks and meet our targets for repairing them,” Nama says. “We’ve also had fewer leaks reported this summer, which could be due to the proactive leak detection work, as well as the little bit more rain we’ve had compared to last summer.

“Our meter readers are doing a great job of reporting leaks when they come across them. Sometimes these are leaks in private pipes and if that’s the case, we ask the customer to get them fixed as soon as possible.”
Nama says there are many causes of leaks, including ground movement in extreme weather, wear and tear in older pipes and vibration damage from heavy traffic.

“Parts of central Auckland seem to have more leaks, which could be because the pipes are older, but also because of the roading developments – in some places, pipes that were originally laid under footpaths are now under roads and therefore are more impacted by traffic movements.”

Linda Cooper, our liaison councillor, says the success of the leak detection programme adds to the great work Aucklanders have done to conserve water as part of the city’s drought response.

“The community has done a fantastic job of saving water, which has helped to reduce pressure on our dams. Aucklanders can further support water conservation efforts by helping us minimise the amount of water lost to leaks by reporting them online or by calling 09 442 2222.”

Leaks also occur in private pipes. To learn how to check for a leak, click here.