In water distribution systems, where the area is hilly, there is a natural wide variance in pressures. Properties in valleys will typically have very high pressures whereas properties at the top of hills will have low pressures. This causes problems for both the customer and for us. High pressure leads to leaks and sometimes burst pipes. Low pressure leads to customer dissatisfaction.
Pressure management is the process of balancing and levelling the pressure around the water network. This is a valuable tool for leakage as it can significantly reduce leakage levels and reduce the likelihood of bursts, it reduces the flow rate of leaks and it extends the life of aging water mains giving us additional time to prioritise mains replacement.
Latest case study - Port Erin Pressure Reduction Valve (PRV)
The Port Erin PRV was fitted in July 2022 and is currently saving 77,000 litres of water a day. It has saved 1 million litres of water since being fitted. The PRV is yet to be fully optimised so there are further savings to be made in this area.
Leakage in the area has already reduced from 4.3 l/s to 2.3 l/s which is a 47% reduction.
Pressure is the force used to move water around the water network. Because of the hilly topography of the Island, sufficient pressure is required for properties situated in the uplands.
Properties in lower coastal areas can have high or excessive pressure. This high pressure can cause problems with internal plumbing fittings and appliances. It also puts extra strain on our pipes and fittings causing leaks and bursts.
In 2019 we installed a Pressure Reduction Valve (PRV) feeding an area covering 16 km2, this has reduced the bursts in that area from 19 to 3 per year. Not only were bursts reduced by 85% but 104,000 litres of water is also being saved per day as a direct result of this PRV.
The Island has limited water resources and we need to conserve the water in our impounding reservoirs and rivers; pressure reduction directly contributes towards this.
The areas with excessively high pressure will be investigated for pressure reduction. This is done by installing a PRV on our water main, pressure loggers will be installed throughout the network including a pressure logger at the highest property in the area. The pressure will be reduced very slowly over a number of months and network pressures and flows will be continuously monitored to identify any potential customer supply problems.
Flow is the volume of water that is moved within a pipe. This is determined by the size of the pipe; some small diameter pipes may have fast moving water within it (high velocity). If a pipe is undersized or has internal corrosion this can cause flow problems if the pressure is reduced. Low flow is sometimes confused with low pressure.
The pressure reduction program is for areas with excessive pressure; some customers experiencing high pressure may have already fitted an internal PRV or mistakenly have the internal stop tap partially closed thinking this will reduce the pressure when it only restricts the flow of water.
Any customers having problems with either pressure or flow should contact us on 687687 and we will send an engineer to investigate the problem and see if we can help.