Ofwat, the water industry economic regulator, sets us annual targets based on achieving levels of leakage where overall costs are minimised - this is known as the sustainable economic level of leakage (SELL).

Below this level it would cost more to fix the leaks than the value of the water lost.

We do everything we can to minimise the risk of leakage but it is impossible to eliminate it completely. Like most other things our network of mains wears out and suffers damage from the external environment, for example from ground movement associated with freezing temperatures or very dry weather and the impact of traffic on the roads.

Monitoring and detection
Within our network of mains we have very large water meters that measure the flow of water as it passes through into a zone, and area of pipes.

By comparing readings, we can rapidly identify if there is a leak within the metered zone. We have teams of leakage technicians who are dedicated at looking for leaks all over our supply area.

We also rely on people to report leaks whenever they see them, without the support of our customers, we would not be able to locate nearly as many leaks as we do.

Customer side leakage

Leaks often occur on private property, which is known as customer side leakage.

We will always let you know if we find a leak on your property. We offer a leak assistance service which helps to reduce leakage on the parts of the pipe network we don’t own.

Controlling network pressures

By installing special automated equipment at key points in our network, we are able to regulate the pressure of the water. By smoothing the flow and changes in pressure, we are able to minimise the stress put on water mains, and reduce the risk that a main will burst.

Prioritisation

Once we know about a leak, we schedule it for repair. At any one time there may be many dozens of leaks around our network, so we have to prioritise them.

We use a number of factors in the prioritisation process, including risk to safety, disruption to traffic and the volume of water being lost. Generally that means that larger leaks will be fixed first.

Future plans to reduce leakageWe want to do more to reduce leakage so have set ourselves an ambitious and stretching target of reducing leakage by 17%.

In our business plan we set out our plans to do this:

• We will invest £7.5 million in a smart network to give us better information about how our network operates. This will allow us to improve the way we manage our network to prevent leaks occurring and minimise supply interruptions to our customers
• We have set ourselves an ambitious performance commitment to repair 90% of visible leaks within four days by 2024/25. 
• We will make more use of satellite detection technology and automated leakage detection systems, such as acoustic logging, so that we can identify leaks quickly. This will also help us to prioritise our resources more effectively
• We are investigating the use of an innovative, sector-leading approach to fix leaks without the need to pinpoint their exact location or dig up roads.
• We will focus our repair and maintenance programme on those sections of pipe that our investigations suggest may be prone to bursts or leaks.
• We will expand our current programme of water pressure management. We can lower the pressure in some parts of the network without impacting on the service we deliver to customers;
• We will continue to develop our assisted-repair policy for customers’ supply pipes – making sure we support customers effectively and fix any problems quickly. Our analysis suggests that leaks on our customers’ supply pipes (what we call ‘customer-side issues’) could equate to more than 30% of our total leakage.
• We will continue replace sections of our network that are coming to the end of their serviceable life and that can no longer support the levels of service both we and our customers expect.

Beyond 2025, we are targeting further reductions to ensure that by 2045, no more than 10% of all the water we produce is lost to leakage within our network.