Fibre Cables Turn Leak Hunters Beneath UK Streets

A UK pilot using telecoms fibre and AI found over 100 leaks across 650 km, saving 2 million litres of water daily

13 Mar 2026

Fibre-optic cables buried beneath parts of southern England are being used for a new purpose: detecting hidden leaks in water pipelines. In a recent pilot project involving Affinity Water, the telecom infrastructure provider Openreach and the artificial intelligence firm Lightsonic, existing broadband cables were repurposed to monitor sections of the region’s water network. The trial suggests that telecommunications infrastructure already installed underground could help utilities identify leaks far earlier than traditional inspection methods allow.

According to the companies involved, the system monitored roughly 650 kilometers of Affinity Water’s network over three months. During that period, it identified more than 100 leaks and helped prevent the loss of about 2 million liters of water per day. The recovered volume, the companies said, is equivalent to the annual water needs of roughly 10,000 people.

The approach relies on a technique known as Distributed Acoustic Sensing. The method transforms fibre-optic cables into dense networks of virtual sensors capable of detecting vibrations along their entire length. When pressurized water escapes through a crack or fault in a pipe, it generates acoustic signals that subtly disturb the light traveling through nearby fibre. Lightsonic’s machine-learning systems analyze those disturbances, filtering out background noise such as traffic or construction activity and identifying patterns associated with leaks. Engineers can then pinpoint suspected faults within a few meters and carry out repairs more quickly.

Utilities may find the economic argument particularly compelling. Because the monitoring system uses fibre cables already laid for telecommunications, companies avoid the cost and disruption of installing new sensors or inspection infrastructure. In densely populated regions with extensive fibre networks, the technology could potentially monitor large sections of water systems with relatively little additional hardware.

Regulatory pressure is also intensifying efforts to reduce water loss. The European Union’s Drinking Water Directive calls on member states to address high leakage rates, while Britain’s regulator Ofwat has made leak reduction a central benchmark for water utilities. Trials like this one suggest that digital monitoring tools built on infrastructure already beneath city streets could play an expanding role in modernizing aging pipe networks and narrowing the gap between when a leak begins and when it is repaired.