Every day we treat nearly 1,400 million litres of wastewater, to some of the highest regulatory standards in the world.
But when there is heavy or prolonged rain, our network has to cope with rainwater run-off from roads, roofs, driveways and hard surfaces. Storm overflows are there to help protect homes, businesses and schools from flooding. They are effectively a pressure release valve, activated when the system’s capacity is exceeded.
Storm overflows are regulated and permitted by the Environment Agency. And, while these releases from our network do comprise of some water that has not been fully treated, discharges are typically heavily diluted and made up of 95% or more rainwater.
A spokesperson for Southern Water said:
“We are investing and taking action to reduce the use of storm overflows and lead the way towards creating healthier rivers and seas.
“We have committed to investing £2 billion over five years to improve our performance. This will help us to reduce 80% of our pollution incidents by 2025 and significantly reduce storm overflows by 2030 by improving our wastewater assets and environmental performance. “
Notes to editor:
- Since privatisation, Southern Water has improved the volume of wastewater that is fully treated before release back into the environment, from 30% to 95%, through investing £10bn.
- The improvements we have made already mean that 80 of the 83 coastal bathing waters in our area are recognised by the Environment Agency as either good or excellent, and none are considered poor. Before privatisation, only 28% of bathing waters in the UK met the minimum public health standards.
- Our sewer network is designed to flow largely unassisted with gravity and a base level of flow, meaning all contents in the sewer make it to a pumping station or treatment works. However, this is not the case in times of dry weather so heavier materials (rags, unflushables, grit, woody debris, etc) settles and sits in the sewer. As heavy downpours hit, there will be a sudden influx of wastewater into the sewer network which flushes out the sewer and clears a lot of the debris that has been sat there, suddenly transporting it to pumping stations, inlets, etc. This can lead to blockages forming, pumping stations getting clogged up and can cause potential floods and storm overflows to open.
- Our Beachbuoy system provides near real-time information on storm overflow activity which may have an impact on bathing waters
- Southern Water has ambitious targets to significantly reduce storm overflows by 2030 across our region and has set up the Clean Rivers and Seas Task Force to pilot innovative and collaborative ideas through Pathfinder projects.
- We’re working in collaboration with residents, businesses, councils and other local organisations to test a range of solutions to divert rainwater back to the environment in sustainable ways, working in partnership with local communities to slow the flow of surface water entering our network and reduce the use of storm overflows.