Portsmouth and Southern sign Bulk Supply Agreement for Havant Thicket

Portsmouth Water and Southern Water last week formally signed a new Bulk Supply Agreement (BSA) for provision of water from the planned Havant Thicket Reservoir.

Under the 80-year deal, Portsmouth will supply 21 million litres of water a day to Southern, up to a 1 in 200-year drought. The BSA is novel in that it allows large scale infrastructure to be developed across water company service area boundaries (Portsmouth will construct the reservoir purely to cater for Southern Water’s needs rather than its own). This is the first time that a UK reservoir has been developed in this way and provides a precedent that other water companies can potentially follow.

The BSA contains protections for Southern Water customers to incentivise Portsmouth to continue to supply water, and Ofwat has specified regulatory protections for both parties to ensure the reservoir is built and operated for the benefit of customers.

Portsmouth already has agreements to share up to 30 million litres of water a day with Southern Water in West Sussex and Hampshire, and can share a further nine million litres a day from 2024 from other sources. Once the reservoir is built, Portsmouth’s total provision to Southern will be 60 million litres per day.