A groundbreaking technology trial – which uses Openreach's fibre network to detect leaks in surrounding water pipes – has managed to prevent the loss of 2 megalitres of water – equivalent to the daily use of around 10,000 people, in just three months.

Working with Affinity Water and UK technology company Lightsonic, the pilot uses Distributed Acoustic Sensing (DAS) – which converts Openreach’s fibre optic cables into thousands of sensors that can ‘hear’ and pin-point leaks from surrounding water pipes.

The project aims to help companies like Affinity Water tackle one of their biggest challenges – with England and Wales losing around three billion litres of treated water daily through leaks– equivalent to the daily water use of more than 20 million people. That’s around a fifth of the country’s water supply, highlighting the urgent need for action. Affinity Water, along with the rest of the UK’s water industry has committed to halving leakage levels by 2050.

Developed by Lightsonic - the fibre-optic leak detection platform is currently being piloted in five locations – using Openreach’s near ubiquitous full fibre broadband footprint to monitor 650 kilometres of Affinity’s Water’s network. In its first locations, and in just three months, the fibre sensing technology was able to locate more than 100 leaks – saving 2 million litres of water a day – equivalent to more than 700 million litres every year, enough to supply around 10,000 people.

Trevor Linney, Director of Network Technology for Openreach, said:

“The results of our pilot show that our new full fibre infrastructure can deliver value far beyond broadband – and could prove to be a real game changer in solving real-world challenges like water conservation.”

“Around 20 per cent of the UK’s drinking water is lost to leaks with water conservation a significant and growing issue for the nation. And, what’s great about this technology, is that it can be used to detect a whole range of things – from gas leaks to monitoring the health of big structures like bridges and tunnels. It has huge potential.”

Tommy Langnes, CEO of Lightsonic, added:

“Transforming the telecom fibre-optic network into a continuous sensing layer unlocks entirely new ways to monitor utilities. Detecting 2 megalitres per day shows what’s possible when fibre sensing solutions and existing infrastructure are combined at scale.

“This collaboration demonstrates how fibre sensing can deliver measurable environmental impact today, while creating solutions for wider utility monitoring in the future.”

How the technology works

DAS technology works by detecting changes in the light signal used in fibre optic cables caused by vibrations from a leak or disturbance in surrounding networks. It uses machine learning to locate the exact point of the vibration, and it trains the system to separate background noise – like the rumble of traffic or roadworks, so that leaks stand out clearly — even in busy streets. The technology has big advantages over conventional detection methods, namely:

Continuous monitoring: Existing leakage detection relies on targeted surveys and skilled field teams working systematically across the network. Fibre sensing complements this approach by providing 24/7 monitoring, so leaks can be spotted sooner and reduce the time between surveys.

No need to dig: It uses the fibre that’s already in the ground — turning it into thousands of tiny “virtual sensors” - making it cheaper, quicker, and more environmentally friendly.

Targeted identification: The system recognises the unique acoustic “signature” of a potential leak and highlights an area to investigate – often to within a few metres, so repair teams are directed to the right spot.

Reduced disruption: By identifying leaks earlier, water companies can address them before they cause significant disruption, cutting emergency callouts and minimising impact on customers and road users.

Easy to scale: Using the national reach of Openreach’s fibre network means the system can be scaled up across throughout the UK.

James Curtis, Head of Leakage at Affinity Water, commented:

“Strengthening how we identify and address leaks is central to our leakage strategy. By working with Lightsonic and Openreach, we’re enhancing our existing detection programme with continuous network monitoring, helping our teams target areas of interest more quickly and reduce the time leaks may run before repair.

“This technology complements the expertise of our field technicians, supporting earlier intervention, better planning and reduced disruption for customers — all by using fibre that’s already in the ground.”