Southern Water has recorded a record breaking year for finding and fixing leaks – thanks to new technology on the streets and in the control room.

Between April 2024 and April 2025, the water company reduced weekly leakage by more than 15%, from 108.1 million litres per day to 91.1 million litres per day - saving 17 million litres every day, enough to serve 35000 customers.

Southern Water technicians no longer use 'listening sticks' to hear leaks but have moved on to computerised acoustic loggers - 24,000 acoustic sensors are attached to the firm’s 15,500km water network which send intelligence straight back to the control centre.

Any problems are sent to 90 teams of leak busters who are on the ground across the region, ready to pinpoint any issues as quickly as possible.

Overall, during the 12 months, the utility’s proactive work saved a total of 138.7 million litres per day, which would otherwise have been lost through leaks. This compares to only 107.7 million the previous year – a 28.8% boost, representing the biggest cut in Southern Water’s history, and around a fifth of the average amount of water we put into supply at 566 million litres per day.

Tim McMahon, Managing Director of Water, said:

“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. 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.”

In addition to the use of acoustic devices, which pick up the tell-tale hiss of a split in a pipe and the gurgle of a full break, the company is also exploring other innovative technologies to help moving forwards.

Southern Water currently has around 160 employees undertaking leak detection activities, either repairing leaks on the ground, or working in the control room on planning, reporting and performance improvement.

In total, teams repaired 20,820 leaks on its network last year, as well as 3,488 repairs to customers’ own pipes.

However, preventing leaks from happening in the first place is another challenge.

Tim McMahon continued:

“We have our biggest ever water mains replacement programme underway with 50km of older PVC pipes being replaced by the latest technology during 2025 alone.

“But with more than 15,000km of network mains, replacement has to be carefully targeted. Managing pressure in pipes to prevent spikes can stop the older mains from splitting and prevent leaks – and stop customers from losing pressure.”