Major milestone in £50m upgrade at Southport Wastewater Treatment Works
United Utilities has reached a major milestone in its £50 million upgrade at Southport’s Wastewater Treatment Works.
Works to construct and install the structural walls of a large stormwater tank have now been completed on site, with further testing and engineering work continuing through the summer before the tank is brought into service in late 2026.
The tank is capable of holding up to 4,500m³ of stormwater during periods of heavy rainfall – equivalent to 2.5 Olympic-sized swimming pools or 30,000 bathtubs. This will complete phase one of the project.
A second phase is expected to complete by summer 2029 and will further increase the site’s ability to treat more wastewater during heavy rainfall.
The upgrade will play a key role in enhancing water quality along the Sefton Coast by reducing the number of times storm overflows operate during heavy rain.
Steven Kenyon, County Business Lead for United Utilities in Merseyside, said:
“We are committed to continuous improvement to our infrastructure, and upgrades to Southport’s wastewater treatment works are a priority.
“From increasing storage on site to looking at bespoke solutions such as sustainable drainage and new, innovative ways of treating wastewater to even higher standards, we are starting to see the impact our investment is making. This is helping us make great progress in reducing spills and improving water quality.
“We continue to review our network and sites across the county to identify where we can make further improvements that help reduce the number of times storm overflows need to operate.”
The investment forms part of United Utilities’ £13 billion ‘Big North West Upgrade’. Over the next five years, the investment will deliver new infrastructure, improve water quality, replace old water pipes, reduce leakage to its lowest-ever level, and protect over 500km of rivers and bathing waters — reducing the use of storm overflows by 60% over the decade to 2030.
The project at Southport WwTW is being delivered through United Utilities’ Enterprise delivery model, which brings together seven design and construction partners, plus United Utilities, into one integrated team.
