FOR Lee Leonard, the old-fashioned listening stick comes top of the list.

Lee has worked in leakage for 25 years, detecting escapes of water from underground pipes. He uses a range of methods, from the simple stick - a metal or wooden pole with an earpiece attached to one end - to more advanced technology such as satellite scanning and high-tech cameras.

“We use correlators, night sounding and ground microphones,” says Lee, a senior leakage inspector with Bradford-based Yorkshire Water. “Over the years we have seen the introduction of methods including pressure-reducing valves, gas detection and ground penetration cameras. But mostly it comes back to the listening stick to pinpoint the leak.”

Dating back centuries, listening sticks - which work in the same, simple, way as an ear trumpet - have been a reliable tool for leak detection, and there are many different kinds available. While it may be impossible to hear the sound of a water leak on the surface, in pipes the sound of a leak under pressure can travel through water in every direction and the sensitive stick can help to find the source.

Causes of leaks vary, but older pipes are more susceptible, says Lee. “The main cause is generally ageing pipes, and mostly in metallic pipes, but sudden surges in pressure on the network can also cause leaks.”

He adds: “We do get leaks on the new plastic mains and services sometimes. These are a lot harder to find as the noise doesn’t travel down the plastic material in the same way.”

Every day more than 31,000km of mains network deliver over one billion litres of water to homes and business across Yorkshire.

Currently, Yorkshire Water deals with around 5,500 leaks on its network each year which costs around £19,000 per day to investigate and repair.

Last December the company announced plans to reduce its leakage rate by 40 per cent by 2025, saving millions of litres of water lost each day.

The firm has committed to hiring 50 new leakage inspectors as part of a multi-million pound drive to improve the service it offers to its five millions customers.

While listening sticks are a tried and trusted method of leak detection, technological innovation is reaping rewards in the fight against water losses.

Yorkshire’s leakiest pipes - including some in Bradford - are being fitted with thousands of specialist ‘acoustic ears’ to enable Yorkshire Water staff to listen and quickly respond to potential problems on its underground water pipe network.

Up to 40,000 acoustic loggers capable of listening to the flow of water, will be attached to fittings on water pipes throughout Yorkshire.

Placed at intervals on distribution mains, the high-tech devices listen for the noise of escaping water that follows a leak or burst. When such a noise is detected it transmits an alert, together with an audio sound file, to Yorkshire Water’s 24-hour central control room in Bradford.

This data is then analysed to help identify underground leaks and send a response unit out to quickly to repair it, helping to potentially save millions of litres of water. The noise and flow pattern will allow expert technicians to understand the sound of water to help reduce the risk of bursts or leaks caused by high pressure.

The system links in with a Geographic Information System (GIS) to help the workforce act on the information as quickly and efficiently as possible. If bursts and large leaks can be identified within hours rather than days or weeks, with a high degree of accuracy, then repair teams can be dispatched quickly.

“My job at the moment is very exciting as I am part of the new technology team,” says Lee. “We’re fixing loggers to the water mains network around Yorkshire which will alarm when noises are detected between the hours of 2am until 4am. The system will pinpoint the exact locations of noises for us to follow up.”

Steve Mallinson, networks and grid optimiser at Yorkshire Water said: “We’ve created a bespoke system that allows us to really understand the water patterns in our pipes. It will give us a vast amount of data that can be analysed to help control the flow of water and prevent bursts and leaks happening.

“It will also help us to try and repair any issues within just three hours, rather than the current average of three days.”

Satellite space technology used to hunt for water on other planets in the solar system is also helping to identify underground water leaks.

The company partnered with Israeli company, Utilis to test out the technology on its pipes in Keighley and Halifax. The trial helped identify 44 underground pipe leaks that were quickly fixed. It was calculated by the firm that this helped save 330,000 litres of water a day escaping.

“We are also following up 300 points of interest from satellite detection - this system detects saturated ground within a 100 metre radius and can detect treated water,” says Lee. “This will reduce locating time.”

Jason Griffin, Yorkshire Water’s leakage team leader in West Yorkshire says: “Most leaks from our pipes do not come to the surface and so are hard to identify. This makes it much easier for our inspectors to pinpoint and repair. On the back of this, 44 leaks were repaired and this helped stop a significant volume of water escaping.”

Dave Stevenson, head of water distribution at Yorkshire Water, adds: “Detecting a potential leak on a water pipe is not an easy thing to do but this technology will enable us get to problems on our pipes faster, preventing bigger bursts and helping us reduce the amount of water that is lost.”

In some areas of Yorkshire, drones are being used to fly along underground water pipes to conduct topographical surveys. The footage enables Yorkshire Water to spot leaks that it might not previously have known about.

The work forms part of a wider multi-million pound package announced by Yorkshire Water that will create 300 new jobs.

To those at the sharp end, fixing a leak is always rewarding. Says Lee: “ It’s very satisfying to me when I’ve pinpointed the leak, seen everything go to plan from start to finish and got it right first time. It is also nice to see the area leakage drop as a result of it being repaired.”