Low rainfall and high consumption is putting pressure on water supply. One clear way to reduce water use, and therefore cut water bills, is to resolve leaks.
Water companies are working hard to cut leaks in their systems, with an estimated 1 trillion litres lost across the UK in 2021.2 But users, including schools, also need to play their part. Many organisations are looking to improve water efficiency through things like automatic taps, but leaks remain a major source of loss. This not only wastes water, but costs money too. Godalming College will save more than £8,000 a year after Wave found and fixed a leak which had evaded previous investigators. Godalming College is a specialist in sixth form education based in Godalming, Surrey. When the college joined TEC’s Managed Water and Wastewater Framework, they took the opportunity to address a problematic leak which two contractors had failed to rectify.
In September 2021, Wave was chosen from the TEC framework as the College’s water supplier to investigate the leak. The College was using almost 30 m3 of water per day when it expected to only use around a third of that. Several factors made the investigation more challenging. Unusually, the site had no main internal stop tap valve, making it harder to narrow down the leak location. Other internal valves were also faulty.
Adding to this, work could only take place at the weekend to avoid disrupting the school. Once Godalming College had replaced the faulty valves, Wave could carry out a thorough investigation, which was booked in October. The first step was a leak detection survey to try and find the
location of the leak. This involved techniques such as acoustic surveys which use sound to find the leak.
This survey significantly narrowed down the potential leak location by ruling out leaks in the main college building, and between the meter and point of entry into the building. This left one possible location another water supply running from the outdoor tap to an additional building that houses the canteen, boiler room and kitchen.
Wave capped off this supply and found the water meter stopped, confirming the leak was on the network. However, digging a trench to excavate the entire pipe would disrupt the college. Instead, Wave suggested moling, a trenchless method of laying pipes. During this process, a pneumatically driven machine forces its way through soil along the desired path of the pipe. Not only does this save the time and cost involved in a full excavation, it also makes reinstatement much simpler. Godalming College agreed with Wave’s suggested approach, so the works were carried out over a weekend in November. Wave replaced 40 metres of pipework and connected the new supply to the existing network. However, while this significantly reduced the leakage, the water meter showed there was another minor issue on the network.
After some more investigation, Wave found that urinal cisterns were continually filling, leading to a waste of 0.4 litres per minute. While this might not sound like much, each uncontrolled urinal can lead to a loss of £700 per year. With all leaks fixed, Godalming College was back to their expected water consumption, saving more than £8,000 per year. And by proving to Thames Water that some of the water the College consumed had gone into the ground and not into the sewers for processing, Wave was able to claim back £4,850 on behalf of the College.
