Southern Water uses fibre optics to detect water leaks

Southern Water has begun implementing a fibre-optic leak detection system, developed by the UK firm Lightsonic, as water companies face increased pressure from drought and aging infrastructure across the south of England. The technology allows the company to monitor parts of its network by converting existing telecommunications fibre into acoustic sensors capable of detecting the sound of escaping water and pinpointing leak locations.

Reducing water loss and meeting targets

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The company stated that the system is expected to accelerate the discovery and repair of leaks, reduce water wastage, and assist Southern Water in meeting its regulatory targets. This initiative follows a summer where nearly three-quarters of England experienced drought conditions, leading to exceptionally low reservoir levels in many areas. Southern England has been identified as a particularly water-stressed region, with an estimated 2.6 billion litres of water lost daily from England's network due to leaks.

Approximately 60% of water mains in the UK are at least 45 years old, and about 13% were installed over a century ago. Lightsonic reported that its system has already contributed to saving more than 4 million litres of water daily across about 650 kilometres of network in the UK by identifying and locating leaks. The company claims its technology is faster and more precise than some current detection methods, providing alerts that help maintenance teams prioritise critical issues and reduce the need for multiple site visits.

We’ve been impressed by the leakage reduction metrics and proven success of Lightsonic’s technology and are looking forward to working with the team as we head into winter, when colder conditions can result in more leaks, to trial a new way of detecting and tackling them.

Wayne Novelli, Southern Water leakage and network strategy manager

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For water companies, such improvements carry regulatory and financial implications. Ofwat has established leakage reduction targets that mandate substantial cuts by 2030, and utility providers are under increasing scrutiny regarding their performance and investment in network upgrades. Southern Water selected Lightsonic following trials and its existing deployments with other companies, including Affinity Water and Openreach.

Scalable solution for water stress

Tommy Langnes, chief executive of Lightsonic, commented that ageing infrastructure, leaking networks, and mounting climate pressures are creating significant water stress. He added that by using existing fibre optic infrastructure, the system offers a solution that can be rapidly and effectively scaled across the UK. This helps utility companies manage leaks, secure supply, and generate savings that can be reinvested in upgrading aging networks. Langnes stated that the industry requires a swift and comprehensive response, which his company provides.

Trevor Linney, director of network technology at Openreach, noted that their existing trials with Lightsonic demonstrate that their full fibre infrastructure can offer benefits beyond broadband. He suggested it could be a significant factor in addressing real-world challenges like water conservation. Linney explained that combining Lightsonic’s technology with the extensive reach of Openreach’s Full Fibre network makes continuous utility monitoring genuinely scalable, without the expense and disruption of building a separate sensor network.

What happens next

Southern Water will continue to roll out the Lightsonic system across its network. The company aims to improve leak detection and repair efficiency to meet regulatory obligations and reduce water wastage, particularly as it heads into winter when colder conditions can exacerbate leaks.