Slyfield Sewage Treatment Works


Relocation of the Guildford Sewage treatment workks


Approved Work Starting


As part of the Slyfield Area Regeneration Project (SARP) in addition to the Weyside Urban Village the Slyfield Sewage Treatment works is being moved to a new site freeing up a considerable area for housing.

The Scheme consists of:

  • A new STW located to the north-east of the existing Slyfield Industrial Estate in Guildford to replace the existing Guildford STW
  • New effluent and stormwater outfall pipes to the River Wey, to the northeast of the new STW
  • A new gravity transfer tunnel, running from the existing inlet pumping station to the new STW, to transfer incoming wastewater from existing sewers to the new STW

Thames Water are in the process of finalising plans and have a program of works until late 2026

Project Phasing 

Phase 1: Ground improvement (early August 2023 to Spring 2024)

Improving the ground at the new site that has been used as Landfill in the past.

Phase 2: Civil engineering (Autumn 2023 to Summer 2025)

Laying pipes and foundations on the new site

Mechanical and electrical engineering (Summer 2024 to Autumn 2025)

Installing the Pubs and treatment mechanics.

Phase 4: Commissioning (Winter 2025/26 to Autumn 2026)

Transferring treatment activities across from the old plant to the new plant.

Transfer tunnel (August 2023 to Summer 2024)

To avoid massive changes to exiting sewage pipes the new plant via a transfer tunnel will intercept existing sewage pipes and transfer the flows across to the new site.

STW Plans

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