The Hampshire Water Transfer and Water Recycling Project (The Project) is a Strategic Resource Option (SRO) and a major part of Southern Water’s long-term strategy to address the significant water supply shortfall in Hampshire. By using advanced water treatment technologies, the Project will transform treated wastewater, normally pumped far out to sea, into purified recycled water. This new resource will supplement natural spring water from Portsmouth Water’s Bedhampton Springs, with both sources being stored in the new Havant Thicket Reservoir. This integrated approach will maximise the reservoir’s capacity, ensuring greater water availability, especially during periods of drought. Water from the reservoir will be transferred to our existing Otterbourne Water Supply Works, where it will undergo further treatment to strict drinking water standards prior to going into supply. By establishing a sustainable and resilient water source, the Project will help safeguard essential water supplies for our customers while reducing reliance on environmentally sensitive water sources. The Project consists of a Water Recycling Plant, tunnel and pipeline connections, a High Lift Pumping Station, and a circa 42 km transfer to Otterbourne Water Supply Works inclusive of intermediate pumping stations and break pressure tanks. The Project scope includes Design, Build, Finance, Maintain and Operate (DBFOM) of new water infrastructure, including water recycling, water transfer, and substantial tunnelling works. The Project will be procured using Ofwat’s Direct Procurement for Customers (DPC) model, with a Competitively Appointed Provider (CAP) to deliver the DBFOM project. Under the DPC model, Southern Water plan to openly tender for a CAP. Southern Water has carried out several market engagement exercises to support this procurement. Southern Water does not guarantee that all activities referenced by the CPV codes will form part of any future tender notice(s), nor is the list exhaustive of all activities which may be included in any procurement process under this Project.

Procurement Act 2023

Utilities

Southern Water (SW) commenced market engagement 4 (ME4) on 6th February 2026 ( (Preliminary Market Engagement Notice 2026/S 000-010912) it included: • Market Survey • Requests for Information (RFIs) Pack comprising an RFI questionnaire and key information on the Project • Townhall Event • A number of bi-lateral meetings with selected participants seeking feedback in particular from investors, construction and operating and maintenance contractors and/or potential consortia (which may involve their wider supply chain) that may be interested in the Project. SW will now continue this ME4 engagement through its new sourcing portal, Coupa, and invites all interested parties to register and express their interest in the forthcoming Coupa event to ensure ongoing communication. All interested parties (whether they participated in the earlier market engagement or are now expressing an interest) are also encouraged to participate at this stage, and all previous materials and updated information will be made available through the Coupa portal. https://supplier.coupahost.com/quotes/public_events?customer=southernwater&company_name=Southern+Water SW will provide the market with a summary of the key updates to the Commercial Overview and Procurement Overview documents provided as part of the previous RFI exercise. SW may undertake further market engagement on these updates in November 2026, prior to tender launch in January 2027. The basis on which this market engagement exercise is carried out is as follows: • Southern Water may continue this market engagement exercise as long as it considers it necessary and expressly reserves the right to conduct such other activities that it considers necessary, details of which will be provided through the Coupa portal; • To the extent that feedback is requested at any point during this market engagement exercise, Southern Water may choose not to consider or implement any or all of the suggestions made through this market engagement exercise, or may at its discretion use the outputs from this exercise to shape and refine any aspect including the procurement process before any formal competitive procurement process is launched; • The market engagement exercise is not a formal request for participation in any procurement. Involvement in this exercise will not confer any advantage or disadvantage on any person in respect of any future competitive procurement processes launched for the Project; • Respondents should note that information provided in response to the market engagement exercise may be disclosed by Southern Water to its directly appointed advisers and consultants (all of whom are subject to obligations of confidentiality as part of their appointment) and / or to other stakeholders such as regulators. The information provided in responses may also be disclosed, in a suitably summarised and anonymised form, to other stakeholders and to other interested persons; • Southern Water is not obliged to respond to any correspondence related to the market engagement exercise. Direct or indirect canvassing of Southern Water (or any person connected with it) by any person concerning the market engagement exercise, or any attempt to procure information outside of the defined process is discouraged and may (in certain circumstances) require the disqualification of the relevant person(s) from participation in any future competitive procurement process; • Any costs of participation in this market engagement exercise will be borne by the interested person. Southern Water is using an electronic tendering portal, Coupa, which can be found at: https://docs.coupa.com/en/supplier-documentation/coupa-for-suppliers/the-coupa-supplier-portal-or-csp It is free to register on the portal, which can be accessed at any time of day.