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.

The water company’s technicians no longer use 'listening sticks' to hear leaks but have moved on to computerised acoustic loggers.

Previously, the old way of finding a leaking water main was by pressing one end of a rod to the pipe and placing the other end against a worker’s ear to feel the unique vibration of a burst.

Now, 24,000 acoustic sensors are attached to Southern Water’s 15,500km water network which send intelligence straight back to the control centre.

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

The new approach is proving a big success - between April 2024 and April 2025, the utility 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.

Overall, during the 12 months, this 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 the company’s history, and around a fifth of the average amount of water put into supply at 566 million litres per day.

Tim McMahon, Southern Water’s Managing Director of Water, said:

“There’s been incredibly 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 noise of a full break, the company is also exploring other innovative technologies to help moving forwards.

Currently around 160 employees undertake 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 Southern Water’s network last year, as well as 3,488 repairs to customers’ own pipes.

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.”