Written question asked by Joshua Reynolds (Liberal Democrat) on Thursday, 11 December 2025, in the House of Commons. It was due for an answer on Monday, 15 December 2025. It was answered by Emma Hardy (Labour) on Wednesday, 17 December 2025 on behalf of the Department for Environment, Food and Rural Affairs.

Reservoirs and Water Supply: Thames Valley

Question: To ask the Secretary of State for Environment, Food and Rural Affairs, what comparative estimate her Department has made of the cost to consumers of (a) the proposed SESRO reservoir and (b) a Severn-to-Thames water transfer pipeline.

Answer: Water Resource Management Plans, which are approved by regulators, ensure that the strategic options pursued by water companies provide the best value for customers. Expenditure on infrastructure and customer bills are also controlled by Ofwat to minimise costs to billpayers. Defra are working to minimise bill impacts of any strategic resource option through the Water Delivery Taskforce, which brings together regulators and water companies to find cost-effective solutions.

Secondary information