In the UK 3 billion litres of water are lost each day through leaky pipes. The traditional way of looking for leaks on metal pipes is by listening for them. Water leaks can be heard – and the sound of leaking metal pipes can travel long distances along the pipe. Hydrophones (underwater microphones) are used to pick up these signals along water networks like fire hydrants, allowing the location of leaks to be estimated. This method has proved effective. However, the increasing introduction of plastic pipes has made this method unreliable - the leak noise doesn’t travel as far in plastic pipes, so the sound often does not reach the hydrophones placed along the pipe network. An article in The Conversation outlines the challenge engineers face. Around one-third of the UK’s water pipe network is now made up of plastic pipes. Researchers are currently exploring different ways to detect leaks from these - using the fact that much of the noise energy from leaks in plastic pipes radiates into the ground. One way would be to measure vibrations on the surface of the ground to determine the location of the leak. While this approach is likely to work well in rural areas, where the underground space is less crowded and background noise is minimal, it may not be as practical in urban environments. Another solution is to use existing technology, such as fibre optic telecommunication cables. These cables are typically laid along pipeline routes, extensively found in urban areas and sensitive to temperature and vibration, so could potentially be used as distributed acoustic and temperature sensors. New ways of finding water leaks more effectively are beingt researched to reduce water wastage and cost.
