Southern Water has achieved a record-breaking year in leak detection and prevention, thanks to the deployment of smart acoustic sensors and new control systems across its vast network. Between April 2024 and April 2025, weekly leakage was reduced by over 15%, cutting water loss from 108.1 to 91.1 million litres per day—saving 17 million litres daily, enough to supply 35,000 customers.
The success follows Southern Water’s large-scale rollout of 24,000 acoustic sensors across its 15,500 km network. These advanced devices detect the subtle sound patterns of leaks, sending real-time data directly to control centres, where rapid response teams are deployed.
“There’s been incredible work by our teams around the region – finding and fixing the leaks from big pipes far below the ground which show no trace on the street,” said Tim McMahon, Southern Water’s Managing Director of Water. “Thanks to clever technology and new control systems, we are able to prevent pressure spikes which can burst water mains, and work as fast as possible to respond to every reported leak.”
The proactive strategy enabled Southern Water to save a total of 138.7 million litres per day over the year—a 28.8% improvement on the previous year’s figure of 107.7 million litres, and the largest annual leakage reduction in the utility’s history. That’s around one-fifth of the company’s average daily supply of 566 million litres.
In total, leak detection teams repaired 20,820 network leaks and 3,488 customer-side faults. Around 160 employees are now focused on leak detection, both in the field and in control rooms analysing network performance.
Southern Water is also investing in long-term solutions, including its largest ever mains replacement programme. “We have 50 km of older PVC pipes being replaced by the latest technology during 2025 alone,” McMahon added.
With more smart tech in the pipeline, Southern Water is setting the pace for digital-first water management across the UK.
