Water leak detection

We actively monitor water loss in our water networks and undertake a targeted leak detection programme in a different Kāpiti settlement each year.

Our automated systems alert us immediately to drops in pressure in a network for major leaks. Slow leaks though, caused by pipe failure, tree roots, service providers or construction activity, can be harder to identify.

Undetected leaks can waste huge volumes of water and cause extensive damage that's expensive and disruptive to repair. In 2019/20, we estimated water loss in the Ōtaki water network could be as high as 293,000 cubic metres a year, a loss of 233 litres per person per day.

Hunting for leaks in Ōtaki and Waikanae

This year we will be again working with Cardno to hunt out leaky water pipes in our district, using drones and thermal imaging technology to get a picture of what’s happening underground.

During February and March 2022 operators will be in Ōtaki and Waikanae. If you see a drone flying down your street don’t be alarmed – the thermal imaging cameras are designed to see where cool water is leaking into warm summer ground. They won’t be surveying private property, and the cameras can’t see into homes or cars.

In April 2021 we started thermal imaging of our water pipe network in Ōtaki as part of our leak detection programme. In the past we've used traditional technologies to “listen” for leaks using specialist equipment. This works well if the leaking water makes noise and the network has copper or steel pipes, but it doesn't work as well when monitoring Polybutylene pipes – the silent leakers – like those used in the Ōtaki network.

During summer and autumn, soil temperatures are warmer than the water carried through our water pipes. Leaks cool the surrounding area, making thermal imaging a quick and effective way of checking for issues.

To make sure we get a complete picture of the network, the thermal imaging camera is mounted to a drone, and flown down a road. This must be done in the evening to get the best images. This is cutting edge technology in managing water networks, as it picks up leaks that other techniques miss. 

Protecting residents' privacy

Residents' privacy is a top priority. The camera is set to a thermal range that only picks up differences in ground and water temperatures; when set to this range, and travelling at height, people on the street are unidentifiable. The drone does not survey private property, and the camera can't see into houses or cars. Everything that’s not our pipe network appears as darkened objects in the images we capture.

This work is carried out by specialist contractor Cardno, and the drone piloted by a trained operator who is certified for night time operations and complies with aviation safety protocols.