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Southern Water, the privatised utility serving Hampshire, the Isle of Wight, West Sussex, East Sussex and Kent, is deploying leak detection from Lightsonic that reads vibrations in the existing fibre-optic cables of Openreach, the broadband network operator, according to reports published on 23 and 24 September 2026. Lightsonic says its technology now covers 650 km of the UK water network and prevents the loss of more than 4 million litres of water per day, figures that are supplied by the vendor.
How Telecom Fibre Becomes A Leak Sensor
The system analyses small changes in light travelling through fibre-optic cables to detect the vibrations produced by leaking pipes nearby, according to The Register’s report on the deployment. Acoustic sensing equipment is attached to telecom fibre routes that run alongside water mains, and machine learning separates leak signatures from interference caused by road traffic and roadworks before the system estimates where water is escaping.
The approach, known as distributed fibre optic sensing, turns a single cable into thousands of virtual sensors, which is how Kurrantly described the technology when Affinity Water awarded Lightsonic a contract in August 2025 to use Openreach’s existing network.
Leakage Targets And The Drought Context
Water companies in England face leakage reduction targets for 2030 set by the regulator Ofwat, and Southern Water has said that it wants the technology to help meet them while easing pressure on reservoirs and abstraction. Almost three-quarters of England was under official drought conditions after one of the hottest and driest summers on record, and water companies introduced hosepipe bans, according to the reports.
Data Centre Dynamics estimates that about 2.6 billion litres of water are lost to leakage across England’s network every day, so the 4 million litres per day that Lightsonic cites for its deployments is equal to about 0.15 per cent of that daily loss. The reports describe the Southern Water work as a deployment of Lightsonic technology on Openreach’s full fibre infrastructure, and Wayne Novelli, the utility’s leakage and network strategy manager, said that Southern Water has reduced leakage across its network for three consecutive years.
Three Parties With Different Roles
Southern Water is the customer and the party that has to act on the alerts, Lightsonic supplies the sensing equipment and analytics, and Openreach provides access to the fibre. Trevor Linney, director of network technology at Openreach, was quoted in the coverage as saying that full fibre infrastructure can deliver value beyond broadband and that continuous utility monitoring can be made scalable.
Lightsonic had previously worked with Openreach to support Affinity Water, and the 650 km figure covers its UK water network deployments as a whole instead of the Southern Water footprint alone.
Southern Water’s Wider Metering And Monitoring Programme
Leak detection from fibre sits alongside a separate and larger asset programme at the utility. Southern Water awarded a £338 million, 20-year contract to Horizon Water Infrastructure in August 2025 to upgrade more than one million meters by 2030, and the meter data that programme produces is the demand-side counterpart of the network-side signals that fibre sensing provides.
Other UK water companies are testing different sensing routes for the same objective: Northumbrian Water adopted satellite-based leak detection from Origin Tech in August 2025, and Thames Water signed a 13-month contract with the same company in May 2026 that is designed to reduce losses by more than 100 million litres per day.
What Will Decide The Result
Lightsonic’s 4 million litres per day is a portfolio figure, and the measure that will settle the value of the Southern Water deployment is the litres per day recovered on its own network, set against the utility’s leakage trend and the Ofwat 2030 target, together with the speed at which crews are able to excavate once the system has estimated a leak location.
