Thames Water is investing £400 million in an upgrade over the next seven years to improve Coppermills Water Treatment Works in Walthamstow, London - work is scheduled to begin in spring 2026 and will be completed over seven years.

The site is an integral part of supply network The facility has been an integral part of Thames Water’s supply network to London since 1969 and the significant upgrade will enhance the site’s efficiency, reliability and ability to serve London’s growing population.

Upgrades during the seven-year investment programme will include:

• Replacing the 1960s pumping station with a new high-lift pumping station
• A new slow sand filter recirculation system
• Improved power supply through a new electricity substation
• Building new pipes, chambers, and control structures above and below ground.
• Building an electricity substation to power our new equipment
• Moving parts of our security fence (the taller fence inside the site) to make extra space.

Timeline for the upgrade is as follows:

• Planning application for pumping station building - Spring/Summer 2025
• Planning approval works start on site - Spring/Summer 2026
• All works complete - Spring/Summer 2032

Mark Gelinski, Senior Project Manager at Thames Water said:

“Our purpose is to deliver life's essential service, so our customers, communities and the environment can thrive. As custodians of important infrastructure, we need to ensure that our sites are resilient to the pressures of London’s growing population and climate change. Upgrading and investing in our assets is essential to this and this project will mean improved water security for Londoners as we continue to deliver a secure supply of high-quality drinking water for customers across the capital.”