Yorkshire Water kicks off next stage of storm overflow investment with Leeds project

Yorkshire Water has broken ground on its £1.5bn storm overflow investment project between 2025 and 2030, with the first scheme starting in Leeds today (14 August). 

The programme follows a £180m investment over the previous two years, which helped reduce discharges to watercourses by 12% in 2024, compared to 2023. 

Jon Stokes, head of  Yorkshire Water’s storm overflow delivery programme, said: “Our storm overflows are operating more often than we, and our customers, would like, and we’re going to be continuing our hard work into bringing the number of discharges down over the next five years. This will be our biggest ever environmental investment, and we’re really pleased to be getting started with the first project in Leeds.” 

The first of the overflow projects is taking place at Millshaw combined storm overflow in Beeston, to reduce the frequency and volume of discharges into Farnley Wood Beck. 

The £1.2m investment will see the installation of a new storage tank capable of holding 260m3 of storm water – enough to fill 1,576 bathtubs – to help reduce discharges into the Beck. 

Storage tanks build additional capacity into the network, holding excess wastewater during periods of bad weather to prevent it being discharged. Flows will be sent for treatment when capacity in the network has returned to normal levels. 

Contract partners are expected to take around nine months to complete the project. The tank will be built on private land. 

Daniel Rhodes, project manager at Yorkshire Water, said: “In the first year of the five-year programme, we’re going to be investing over £76m into storm overflows projects in Leeds. It’s a significant and challenging programme of works, but one that’s incredibly important for the health of the city’s watercourse and we’re keen to get started. Our investment will bring the number of discharges from these overflows in Leeds down by 72%.” 

The upgrade at Millshaw CSO is the first of 25 planned storm overflow schemes in Leeds set to get underway before April 2026 – and the first of nearly five hundred  schemes across Yorkshire over the next five years.  

Storm overflows are designed to act as a relief valve for the combined sewer network, which carries both wastewater and surface water, during periods of heavy or prolonged rainfall. They discharge when the system is at capacity to prevent flows backing up and flooding homes and gardens. 

Across Yorkshire, the need for storm overflows to operate will be reduced by building new: 

• Surface water sewers, to separate surface water and wastewater so that wastewater networks aren’t impacted by bad weather
• Underground storage tanks, to build additional capacity into the network
• Nature-based solutions, to build additional capacity into the network
• Sustainable drainage systems, to slow the flow of surface water into the combined network 

The storm overflow project is part of Yorkshire Water’s £8.3bn investment into its services and the environment over the next five years.