Southern Water has issued a Request for Information from suppliers with proven expertise in sewer sealing to participate in a preliminary market engagement exercise – the water company is encouraging all interested suppliers to participate.

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:

• Cured-in-place pipe (CIPP) lining
• Pull-in-place liners
• Slip-lining
• Fold-and-form liners
• Full-length polymer coatings
• Targeted patch repairs
• Packer/resin injection
• Chemical/polyurethane grouting
• Cementitious grouts
• Mechanical joint seals
• Manhole rehabilitation
• Top Hat Installation
• Hot cure methods e.g Inversion, Steam Cure, UV light, LED light.
• Other sewer sealing/pathing techniques and innovations
• Other sewer sealing/pathing techniques and innovations

Southern Water is seeking the following information from interested suppliers:

• Overview of experience and proven track record with the major sewer sealing techniques listed (this is not exhaustive)
• Current and forecasted delivery capacity including crews and annual throughput.
• Possible geographical split for delivery including any regional offices, depots, or preferred operating areas.
• In-house technical capabilities and certifications for CCTV surveying, cleaning, lining, injection grouting, manhole rehabilitation and post-work validation.
• Ability to provide turnkey services including traffic management, reinstatement, emergency response and accurate reporting.
• Your appetite for sewer sealing supply chain innovation

Purpose and scope

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.

• Depending on the insights gathered from from the RFI, the water company may follow up with:
• One-to-one meetings (either in person or online),
• A live Marketplace event or townhall session (either in person or online), and/or a second RFI, if deemed necessary.

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 .