South West Water has reduced storm overflow spills in the village of Payhembury in Devon by 57% thanks to a programme of targeted improvements.

During prolonged or heavy rainfall, flows can rise sharply, putting pressure on Payhembury’s sewer system and wastewater treatment works. To tackle the problem, engineers installed two new storm storage tanks at Payhembry. Each tank can hold up to 25,000 litres of wastewater, and excess flows are pumped into the tanks and stored temporarily. Once rainfall eases and there is room at the treatment works, the stored water is then returned for full treatment, reducing the need for storm overflows.

Jenny Eamer, South West Water’s Wastewater Operations Manager for Payhembury, said:

“During heavy rainfall, everything arrives at once - wastewater from homes and water running off roofs and roads. These tanks give us the extra capacity we need to manage those flows safely and ensure the water is fully treated.

“We’re really pleased with the results we’ve seen so far and the progress we are making across the region, but we know there is more to do. As a business, we are investing heavily to improve storm overflow performance, but at a local level it’s so rewarding to see upgrades like this making a real positive impact.”

As well as boosting capacity, South West Water is also investing to reduce groundwater infiltration in the Payhembry catchment. Groundwater infiltration is water that exists underground in cracks and spaces in soil, sand and rock. This extra water can put additional pressure on treatment works like Payhembry, especially during wet weather.

Investigations into other areas of the Payhembury catchment where infiltration may be occurring are ongoing. This work will help South West Water’s engineers target upgrades and reline sections of pipe to prevent leaks in the future, further reducing pressure on the network.