The tendering process is planned to commence in late 2025/early 2026 to support planned sewer sealing work in AMP8, with the contract, which has an estimated value of £120 million (inc VAT) commencing in 2026.
Southern Water said it is committed to reducing storm overflows and managing the volume of water entering the sewer network. A key part of this strategy involves sealing sewers to limit water infiltration and inflow, helping to protect the environment and improve network resilience.
Southern Water is now seeking information on supplier capacity, mobilisation readiness, geographic delivery options, and in-house technical capabilities for both pipe and manhole interventions.
The aim of the market engagement is to assess capabilities to deliver planned programmes using recognised industry techniques for sealing groundwater out of pipes including:
Southern Water is seeking the following information from interested suppliers:
Southern Water are emphasising that the engagement is separate from the Wastewater Network Services - Lot 4, which focuses on reactive repair and maintenance of live assets. Instead, this latest initiative is forward-looking, targeting proactive sealing interventions to support the company’s long-term environmental and operational goals.
The objective is to identify contractors able to programme and deliver sewer sealing works at scale, reduce inflow and infiltration, and restore or improve hydraulic and structural integrity across the utility’s sewer network.
The tendering process is planned to commence in late 2025/early 2026 to support planned sewer sealing work in AMP8, with the contract commencing in 2026. Current estimated start and end contract dates are 1 August 2026 to 1 August 2030 with a further possible extension to 1 July 2033.
Southern Water is reserving the right to engage in further discussions with any organisation, regardless of whether they respond to the initial RFI.
Deadline to respond to the RFI engagement is 15 November 2025 - contact email is
This e-mail address is being protected from spambots. You need JavaScript enabled to view it
.