Skip to contentBack to top of pageThames Water logoThames Water logo
Skip to contentBack to top of page
Thames Water logoThames Water logo
Home
About us
Projects
Work in your area
Guildford mains pipeline project

Guildford mains pipeline project

We’re making major investments to strengthen our network in Guildford, Surrey. This includes the £46m West to East transfer pipeline and the £35m Shalford upgrade. 

Currently, East Guildford is supported only by Netley Mill water treatment works (WTW). So we're constructing a transfer main to connect it to Pewley Reservoir, in West Guildford. This allows us to move water between areas, providing a more reliable water supply for our customers. Work started in February 2024 and is set to finish in Autumn 2026. 

The multi-year upgrade to Shalford WTW will improve reinstatement after outages. It will also enhance treatment performance by 2028.

West to East transfer pipeline

  • Over 99% of pipework is complete, from Pewley Downs Reservoir to Netley Mill WTW
  • Advanced engineering, including 672m trenchless drilling, is now in final system integration
  • Pewley pumping station, balancing tank, and associated works are on track to complete in Summer 2026
  • Extensive testing will take place until completion and handover in Autumn 2026

Shalford WTW upgrade

  • Contact tank improvements to enable inspections and complete any remedial works
  • Increasing supply resilience with caustic soda dosing to adjust pH levels in water output

Community and environment

We worked with Guildford Borough Council to spot potential environmental impacts. We’ve implemented biodiversity enhancements throughout the project area.

Works were delivered with zero environmental incidents, minimised disruption and strong community engagement. This includes direct public commendations.

We appreciate Sir Jeremy Hunt MP's support and candid feedback. This has helped us address local community concerns while moving forward with the project.

How this may affect you

Our working hours will be 7:30am to 6pm Monday to Friday and 8am to 1pm should we need to work on a weekend.

We'll inform residents of any impact by letter. 

Get in touch

You can call us on 0800 316 9800, select option 1 and quote reference BB00455442 to talk about this project.