United Utilities: Listening devices installed to detect leaks
A total of 100,000 listening devices are to be installed underground by United Utilities to detect leaks.
The North West water company said acoustic loggers would listen for sound waves and set off an alarm, alerting engineers to any potential problems.
The technology, which will cost £30m overall, was trialled in Manchester and Liverpool city centres last year.
The firm claims the project has already saved up to five million litres of water a day.
In the first phase this summer, 44,000 loggers will be installed across the North West. A second phase of 50,000 loggers are due to be fixed in place in 2020.
United Utilities' network delivery director Kevin Fowlie said it was "a massive undertaking" to put the devices on the firm's 26,000-mile pipe system, which runs through Lancashire, Greater Manchester, Merseyside, Cheshire and Cumbria.
"Many leaks never show on the surface, so it is a round-the-clock challenge to find and fix them," he said.
"Following the extreme dry weather last year we've seen leakage rates increase due to ground movement."
He added that engineers would be able to "respond faster and more accurately when a pipe begins to leak".