Serving parts of North West London and the Home Counties.

Trunk mains

Keeping the water flowing from the source to our reservoirs is vital to ensure a reliable supply of high quality drinking water for our customers.

That's why between 2015 and 2020 we are installing new and improve existing water mains. These are used to carry vital supplies from our water sources to service reservoirs, water towers and other areas of our network.

Some of our existing trunk mains are becoming old and unserviceable as they were laid more than 90 years ago. They're made from iron and, in some areas, are laid in heavy clay soil that eats into the metal, causing corrosion. This corrosion weakens the structure of the pipe resulting in small holes and cracks appearing over time. As the water leaks through these holes and cracks, the pipe becomes even weaker which can result in a burst water main.

We are currently surveying these old iron water mains so our investment can be prioritised. Most of the old mains will be replaced with new high specification ductile iron, which will provide you with a secure, reliable supply of drinking water and reduce the disruption caused to your community through bursts and leaks.