Southern Water has begun a trial that repurposes existing fiber-optic telecoms cables as underground acoustic sensors. The system, from a company called Lightsonic, runs over Openreach's network and detects tiny changes in light traveling through the fiber to pick up vibrations caused by leaking pipes. Machine learning helps distinguish those signals from roadworks, traffic, and other background noise, and estimates where water is escaping.
Lightsonic claims the technology is already preventing the loss of more than four million liters of water per day across 650 kilometers of the UK water network. Southern Water's trial follows earlier testing by Affinity Water and Openreach in March, which the utility said influenced its decision to participate.
The move comes after one of Britain's hottest and driest summers on record, with almost three-quarters of England officially under drought conditions. Southern Water hopes the trial will support its leakage-reduction targets for 2030 and strengthen drought resilience by easing pressure on reservoirs. Wayne Novelli, the company's leakage and network strategy manager, said Southern Water had reduced leakage for three consecutive years and was looking for innovative ways to find and fix leaks more effectively.
Separately, the utility's record on wastewater remains under scrutiny. A court fined it £2.4 million this week for pollution incidents in Kent, following a £7.1 million fine in July for illegal sewage discharges that closed beaches in Thanet. Both prosecutions were brought by the Environment Agency.