TECHNIQUES used by naval experts for tracking undersea menaces are being put to a new use in Yorkshire - to seek out leaks in underground water pipes.

Technology developed by Ministry of Defence scientists to help surface vessels hunt down enemy submarines could now help Yorkshire Water cut down water supply losses.

It is the first water company in the world to successfully use hydrophones - underwater microphones - to accurately pinpoint the position of water leaks in large diameter pipes over a large distance.

It is part of the water company's bid to radically reduce the number of leaks in its underground network of mains and pipes.

The ability to pinpoint the location of leaks in large diameter pipes with accuracy over large distances could lead to huge savings in lost water, time and excavations.

The use of hydrophones to detect leaks is a well-established technology used by water companies around the world, and involves measuring the length of time sound travels along a pipe between two points.

But until now it only worked over large distances on small diameter metal pipes - on large diameter pipes the high frequency sound waves disappeared into the thick pipe walls before they could be measured accurately.

Updated: 12:27 Monday, December 30, 2002