South West Water has cut storm overflow spills at a Devon site after completing work to upgrade over 280 metres of sewers.
High Bickington, near Umberleigh in Devon, was one of the South West’s highest spilling storm overflows in 2024, recording 233 spills.
Thanks to South West Water’s targeted improvements these spills were reduced significantly in 2025.
To achieve this result, South West Water’s skilled engineers carried out investigations to try and uncover what was causing the storm overflow to spill.
They discovered that surface water and groundwater was leaking into pipes. Known as groundwater infiltration, this happens when water that exists underground in cracks and spaces in soil, sand and rock enters the sewers.
In High Bickington, this water was coming into the sewers and then flowing into the treatment works, causing more water to enter the system than it was designed to take.
When wet weather hits villages like High Bickington, this water can overwhelm the sewer network, leading to spills from storm overflows.
To prevent this from happening, South West Water’s engineers carried out CCTV surveys of the pipes to identify which sections were affected by this infiltration.
They then cleaned the affected areas thoroughly and installed a protective lining to 287 metres of sewer in the area and carried out repairs across the local network, including upgrades to 4 manholes.
When fitted, this special lining is cured inside the sewer to create a watertight seal so no groundwater or surface water can enter the network. Engineers then completed follow-up CCTV surveys to check the lining had set correctly.
The impact of this work is gradual but measurable and saw storm overflow spills reduce by 24% in 2025 compared to 2024.
Charlie Ford, Project Manager for High Bickington, said: “This is another great example of how targeted investment and the hard work of our teams is delivering real results in communities like High Bickington.
“Groundwater infiltration is not something you can see on the surface but it has a real impact on our systems, especially during wet weather.
“By relining pipes and sealing manholes, we’re keeping groundwater out of the network, and as a result we’ve reduced spills and protected the environment.”
High Bickington formed part of South West Water’s £16 million Infiltration Reduction Programme, which targeted 175 high-risk sites after reviewing performance across more than 1,600 storm overflows.
A further 831 metres of sewer pipe in High Bickington have now been surveyed as part of the next phase of work, helping engineers identify where additional repairs may reduce the need for storm overflows even further.