Sealing pipes against groundwater enables Southern to slash tanker use

Southern Water has reported innovative work to seal pipes against groundwater infiltration has drastically cut the need for tankers to prevent its network being overwhelmed and flooding.

The company’s Clean Rivers and Seas Task Force has been working on a Pan Parishes pathfinder project near Andover since late 2022. This has involved sealing or lining 300 private pipes, totalling a distance of 2.5km, as well as 2km of Southern Water pipes, and nearly 70 manholes. Meanwhile, to monitor and investigate the full extent of groundwater infiltration in the area, three boreholes have been drilled, 36 sewer level monitors and 26 temperature sensors installed, and improved technology introduced at local pumping stations to target and measure this issue.

Southern said it previously relied on a fleet of 36 tankers in the area to remove the excess flows, but since Christmas – even in the face of the highest groundwater levels for more than 20 years – it has been able cut that to five – an 86% reduction in use, saving money and community disruption. 

The company indicated the solution could be replicated in other high groundwater regions.

Southern has recently faced local community and media criticism for its reliance on tankers when its network becomes overwhelmed.