Southern Water taps fiber network to sniff out leaky pipes

British water utility Southern Water has begun trialling technology that turns fiber-optic telecoms cables into underground sensors able to spot leaks in its water network. The company is working with UK startup Lightsonic, whose system runs over Openreach's fiber infrastructure.

How the sensing works

No new cables are needed. The system analyses tiny changes in the light travelling through fiber-optic strands to pick up vibrations created by water escaping from a damaged pipe nearby. Machine learning then separates those signals from the noise of traffic, roadworks and everyday activity, and estimates where the leak is located.

Lightsonic says the resulting location data lets engineers reach and repair leaks faster. The approach belongs to a family of techniques known as distributed acoustic sensing, in which the fiber itself acts as a long chain of vibration sensors.

Scale and early results

According to Lightsonic, the technology is already preventing the loss of more than four million liters — roughly a million gallons — of water a day across 650 km (400 miles) of the UK's water network. Openreach, BT's infrastructure arm, and Affinity Water, which supplies parts of southern England, tested the system in March.

Drought pressure and targets

Southern Water decided to run the trial after one of Britain's hottest and driest summers on record, when almost three-quarters of England was officially in drought. Southern England is among the country's most water-stressed regions. The utility says the earlier work with Affinity Water and Openreach influenced its decision, and it hopes the trial will help it meet Ofwat's leakage-reduction targets for 2030 and ease pressure on reservoirs and water abstraction.

"We've reduced leakage across our network for three consecutive years and continue to invest in innovative techniques and technologies to find and fix leaks even more effectively," said Wayne Novelli, Southern Water's leakage and network strategy manager. He added that the company had been impressed by Lightsonic's leakage-reduction metrics and proven success.

Southern Water supplies water and wastewater services across parts of Hampshire, the Isle of Wight, West Sussex, East Sussex and Kent. Its clean-water efforts come alongside a less flattering record on wastewater: this week a court fined the company £2.4 million ($3.1 million) over pollution incidents in Kent, following a £7.1 million ($9.4 million) penalty in July for illegal sewage discharges that forced beaches at Thanet to close. Both prosecutions were brought by the Environment Agency.