South West Water reduces storm overflows by 40% at Cornwall treatment works

South West Water has reduced storm overflow spills by 40% at one of its wastewater treatment works in Cornwall which had the third highest spilling overflow, as it continues to drive improvements in spill numbers across the region.

Beals Mill Wastewater Treatment Works near Launceston had three local storm overflows. There were a total of 450 spills across the three overflows in 2023, including one of the region’s biggest spillers for the year.

Thanks to targeted improvements from South West Water, including closing two of the overflows and diverting their flows to the treatment works, and despite the wettest hydrological year on record, spills in 2024 reduced by 40%.

Groundwater, the water found underground in the cracks and spaces in soil, sand, and rock, was found to be entering the sewers and flowing into the treatment works.

As well as a new screening plant, a new storm tank was installed at the works to store up to 40,000 litres of wastewater – equivalent to around 133 full bathtubs – during periods of heavy rainfall.

These upgrades, combined with improvements to the local pumping station and planned work to repair and reline nearby sewers to stop groundwater getting into the network, will continue to have a positive impact on spill numbers at Beals Mill to help South West Water drive down storm overflow spills across the region.

Karl Stone, South West Water’s Area Operations Manager for East Cornwall, said:

“It’s rewarding to see real improvements taking shape. At Beals Mill, the upgrades we’ve delivered, including new infrastructure and a better understanding of how groundwater was affecting the site, have already led to a dramatic drop in spills.

Our teams live and work in these areas, so we’re personally invested in getting it right. There’s more to do, but we’re committed to keeping up the momentum and making a lasting difference.”

Teams are working to roll out similar solutions across the region which will make South West Water the first water company to meet the government’s target of achieving less than 10 spills per overflow, per year, by 2040.