South West Water has reduced storm overflow spills at one of its highest spilling sites in Cornwall as it continues to drive improvements across the region. The storm overflow at North Petherwin Wastewater Treatment Works, near Launceston, spilled 183 times in 2023.

Targeted improvements from South West Water in 2024 saw spills drop by 55% last year. 

To manage the additional flows that can overwhelm the treatment works during heavy rainfall, and to help protect the local environment, a new storm tank was installed, providing vital storage for stormwater when flows exceed the site’s treatment capacity.

Supported by a new pump system with smart controls, this means that excess flows can be stored on site until the treatment works has more capacity. The flows are then automatically released back into the treatment process to prevent spills to the environment.

The tank has also been fitted with a mechanical screen to remove debris and a flushing system to keep it clean and maintain its performance in the long term.

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

“Every person who works for South West Water is passionate about having a positive impact on the local environments that we call home. That’s why it’s so rewarding to see the difference that improvements like these are having to reduce storm overflow spills in the local area.

“There is more work to be done here and across the wider South West and we’re working hard to deliver more great results like this one.”

South West Water is working to roll out similar solutions across the region which will see it become the first water company to achieve less than 10 spills per overflow, per year by 2040 – a decade ahead of the government’s target.