The Havant Thicket Reservoir in Havant, a collaboration between Portsmouth Water and Southern Water, is designed to safeguard water resources for the South East for years to come.
It will be an 8.7 billion litre storage reservoir spanning 160 hectares in between Leigh Park, Havant and Rowlands Castle in East Hampshire.
The planning application for the reservoir (reference APP/20/00990), along with a separate one for the pipeline which is needed to fill and remove water to supply to customers, was considered and granted permission by councillors at Havant Borough Council and East Hampshire District Council in 2021. A revised pipeline application (reference APP/24/00405) was approved by Havant Borough Council in May 2025.
Havant Thicket Reservoir could open fully to the public in 2031.
Portsmouth Water has set up a dedicated website for the project to keep residents informed of progress.