A groundbreaking trial using Openreach's fibre broadband network to detect leaks in surrounding water pipes has managed to prevent the loss of 2 megalitres of water in just three months, working with Affinity Water and technology company Lightsonic. The results expose both a genuine solution to a costly problem and a broader question about institutional priorities in Britain's privatised water sector.
The technique, dubbed Distributed Acoustic Sensing (DAS), works by analysing changes induced in the light beams carried by fibre-optic cables caused by vibrations from a nearby leak, with machine learning pinpointing the exact source of the vibration and distinguishing genuine leaks from background noise such as traffic or roadworks. The pilot platform was tested in five trial locations in Affinity Water's area of coverage near London, including Walton-on-Thames, Hemel Hempstead, Luton, Chesham/Amersham, and Ware, from which the system was able to monitor 650 km of pipes.
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. That scale matters. England and Wales are losing around three billion litres of treated water daily through leaks, equivalent to the daily water use of more than 20 million people. A solution that can routinely identify a hundred leaks in a small region during a short trial suggests major national potential.
The technology's elegance lies in its efficiency. Traditional leak detection relies on targeted surveys and field teams manually traversing the network, meaning fibre sensing could catch leaks far sooner. Openreach uses spare fibre cables already buried underground, avoiding the cost and disruption of installing dedicated sensing infrastructure. The system converts ordinary broadband cables into thousands of acoustic sensors, creating continuous monitoring across entire networks rather than periodic surveys.
Yet the trial reveals an uncomfortable reality about how utilities operate under Britain's privatisation model. The results depend on whether the torpid privatised water firms in England and Wales view detecting leaks as a priority. Affinity Water appears genuinely engaged, but that may not hold across the entire sector.
The financial incentives are murky. Openreach reports "positive noises" coming from the water industry about adopting the service, with Affinity keen to contract once the trial ends. But adoption costs, who pays for the DAS equipment, and whether savings offset expenses remain unclear. For decades, leakage remained broadly flat as water companies were achieving the "economic level of leakage" where the cost to reduce leakage was balanced against the cost of water lost.
What works technically does not always translate to commercial reality. The trial demonstrates a valuable tool exists. Whether cash-constrained water companies, already facing pressure to reduce customer bills and improve service quality, will prioritise tackling leaks with expensive new technology remains a genuine question. The fibre is in the ground. The sensors work. The science is sound. Now comes the harder part: making organisations actually use it.
The technology may prove transformative, or it may become another promising innovation that larger utilities shelve once the pilot stage ends. The answer depends not on engineering but on whether institutional priorities shift enough to make fixing leaks the financial priority it logically should be.