When boards lead on water

In early 2026, the Havant Thicket Reservoir project team worked continuously for 72 hours to install a 20-tonne steel wall, known as the Culvert Cut Off Wall. It is designed to ensure water cannot escape underneath the embankment, which will be built over the top later this year once the reservoir is filled. The project involves extensive stakeholder engagement, including with key partners in local councils and environmental groups.

The Havant Thicket Reservoir project will be intrinsic to protecting two rare chalk streams in Hampshire. These streams are not only of local but also of global environmental significance. The reservoir will provide a new, sustainable source of water, enabling a reduction in abstractions from these precious habitats in times of drought, leaving more water available for nature.

The reservoir project is funded by infrastructure funds representing institutional investors. Portsmouth Water is currently executing a further fundraising round to raise capital for subsequent construction and delivery phases which will be aligned with policy and regulatory outcomes.

Board action in sync with regulatory reform

Portsmouth Water is just one of the UK water companies tackling serious national water challenges. In the UK Government’s introduction to the Water Industry National Environment Programme (WINEP) methodology, it notes: “The UK Government has declared a climate and environment emergency. If the water sector continues to operate as usual, by 2050 some of our rivers could have up to 80% less water in summer, and it will not be possible to meet the growing demands of people, industry and agriculture. There will be even greater pressure on the quality of rivers, lakes, estuaries and wetlands from pollution.”

Darcy explains: “The UK Government is reforming its regulatory system to support long-term planning of, and investment in, water resources in England and Wales. The Havant Thicket Reservoir project is part of a broader trend, with 33 other major water resource schemes now planned across England and Wales.”

She adds: “The policy framing is that the water sector as a whole needs to get much better at long-term resilience planning, both from the supply point of view but also from a demand management and environmental perspective. This is a significant policy programme at the national level, that is supported by regulation that enables companies to develop these sorts of projects – this is just one of them, but it's the first one and is leading the way.”

In February 2026, the UK Government published a new vision for the UK’s water industry. The White Paper recognises the need to build a series of new reservoirs as part of a significant increase in investment in critical new water resources infrastructure. The UK Government says: “We have already secured a down payment for this transformative change through the £104bn investment programme the water sector will be delivering between 2025 and 2030.”

The UK Government reforms will include publishing a Transition Plan, establishing a Regional Water Planning Steering Group to test new elements of the regional water planning function and introducing a Water Reform Bill into Parliament. All of this will result in a new regulator and new legislation.

A feat of collaboration

For Portsmouth Water, the Havant Thicket Reservoir project is not only in sync with government policy and investor expectations, it also has significant stakeholder and environmental coordination implications. This means working with the Havant Thicket Reservoir Stakeholder Advisory Group and subgroups, and protecting and enhancing nature. Portsmouth Water has committed to delivering an environmental net gain for the area, this includes rewilding 80 hectares of local farmland, improving 5.5km of local watercourses, creating a new wetland and translocating more than 450 trees, saplings and plants from within the site, with the support of volunteers.

“We must ensure that not only are we attracting the right investment but we're taking our customers and our stakeholders with us. In the short-term there will be some disruption, but long term there are massive benefits for customers, communities and the environment,” says Darcy.

“The scope for investment in this area in the UK is huge. Key to the business case is agreement with the regulator about what can be charged to customers going forward.” In effect, what makes this project investible is the ongoing demand which will deliver long-term, stable returns for investors.

Havant Thicket Reservoir is being delivered under an innovative partnership between Portsmouth Water and Southern Water. She says: “Portsmouth Water is building and will operate the reservoir, enabling it to provide water to Southern Water when needed, so it can reduce what it takes from the Test and Itchen, two precious chalk-based rivers in Hampshire. Ultimately, the scheme will be paid for over time by payments from Southern Water to purchase the water it needs to supply its customers.”

Darcy emphasises that we are at a turning point. “We need to think clearly about the value we all attach to water. Changing the regulatory landscape is a good first step. Portsmouth Water is giving the reservoir (and how our customers interact with their water services through smart water metering) the attention they deserve.”