United Utilities cuts storm overflow spills across Cheshire

United Utilities has reported another reduction in storm overflow operations across Cheshire, over the past year, demonstrating further progress on its environmental commitments.

Official figures released today by the Environment Agency (EA) have confirmed a 45% reduction in spill duration during 2025, with the number of spills from storm overflows falling by 33%.   

At the same time, across the North West, the number of storm overflow activations has fell by 22%, while the duration of spills reduced by 27%. 

Across the region, storm overflow operations have now fallen for the past two consecutive years, delivering a combined 38% reduction in spills since 2023. 

Louise Beardmore, Chief Executive of United Utilities, said:

“We’re pleased to show another year of progress in reducing storm overflows across Cheshire and the wider North West. The reductions we’re seeing are the result of the investment we’re making and the hard work of our teams delivering our biggest and most ambitious investment programme for over a century.” 

The company has been delivering a wide range of improvements, including new storage tanks to capture and store wastewater during periods of heavy rain, upgrades to wastewater treatment works, and sustainable drainage solutions which divert rain run off out of sewers and into surface water drainage systems.  

Other infrastructure improvements have included pipework upgrades and the use of AI and machine learning to identify issues such as blockages, so that proactive action can be taken before impacts occur.  

In Cheshire, interventions have strengthened network performance, with improvements at 64 storm overflows preventing 808 activations in 2025. Interventions included the inspection and cleaning of 9,488 metres of sewer, which alone prevented 192 activations.  

While drier weather contributed to reduced spills during the first half of 2025, rainfall over the full year was 101% of the historic average in the North West.  

Louise added:

“Our investment is making a real difference to towns, cities and local communities who want to see an improved and healthier environment for the region’s rivers, lakes and coastlines. We know there’s more to do. Customers have told us that reducing the use of storm overflows is something they care deeply about, and it remains a priority for us.” 

United Utilities is investing more than £13.5 billion in the ‘Big North West Upgrade’ between 2025 and 2030. The programme 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.