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.