Tunnelling and pipeline work has started for Havant Thicket Reservoir after project costs rose to more than £800m and the completion date was pushed back to 2034. Portsmouth Water and partner Southern Water say an extra pipeline has been added to "future‑proof" the scheme and to allow a proposed treated wastewater recycling option—an element that has sparked controversy. Laying two parallel pipes between Bedhampton Springs and the reservoir will use around 1,250 sections and take about three years; the finished reservoir should hold about 8.7 billion litres and help protect chalk streams.
Tunnelling Begins on Delayed £800m Havant Thicket Reservoir as Costs and Timeline Rise
Havant Thicket Reservoir in Hampshire is not expected to be completed until 2034 [BBC]
Work has begun on tunnelling and laying pipelines for Havant Thicket Reservoir in Hampshire, the UK's first major new reservoir project in decades, after the estimated cost rose to more than £800m and completion was pushed back to 2034.
Portsmouth Water, which is delivering the scheme in partnership with Southern Water, said the higher price tag reflects the addition of an extra pipeline to "future‑proof" the development and unforeseen ground conditions under the site that increased complexity and cost.
The extra conduit would enable a proposed water recycling scheme: treated wastewater from Budds Farm could be pumped into the reservoir, then withdrawn and given further treatment before being supplied to customers. That proposal has prompted opposition from some local campaigners.
Laying the two pipes will involve 1,250 individual sections [BBC]
The two parallel pipes will run between Bedhampton Springs and the reservoir. Installation will use around 1,250 individual sections and Portsmouth Water estimates laying them will take about three years.
Ben Ring, managing director of capital projects at Southern Water, said: "Introducing new technology is never without its challenges, but this is tried and tested technology around the world."
Bob Taylor, chief executive of Portsmouth Water, added that installing the additional pipeline now would avoid digging up streets again in future if recycling plans are approved and acknowledged the timeline will be longer than originally planned: "We will make every effort to try and reduce the extent of additional time."
Regulator Ofwat is consulting on increased funding for the scheme as the companies seek support to meet the higher costs. When complete, the reservoir is expected to hold about 8.7 billion litres of water and is designed to help protect the rare chalk streams of the River Test and the River Itchen.
The project aims to boost local water resilience while balancing environmental protections and community concerns over water recycling and construction impacts.
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