Last reviewed 21 June 2021

UK regulator, Ofwat, has threatened to act against water companies that do not address “short comings” in their storm overflow systems, compromising human health and the environment.

The intervention is the regulator’s latest public statement targeting water companies over their poor performance on managing pollution and sewage releases into local water courses.

In a letter to all UK water companies, Ofwat’s new interim Chief Executive, David Black, said company commitments to provide more real-time data on sewage discharges must be delivered.

“It is imperative that each company has a strong understanding of its own performance on storm overflow discharges, and is proactively managing and communicating that performance,” he added.

Storm overflows act as relief valves inside sewage treatment works that allow excess stormwater to be released into rivers or the sea during particularly wet weather.

Discharges of untreated wastewater are only permitted in exceptional circumstances, but data released by the Environment Agency (EA) showed that water companies pumped raw sewage into English waters more than 400,000 times last year. Sewage spills in 2020 increased by 27% over the previous year, which the EA attributes to “higher number of overflows being monitored”.

Black said he expects all water companies to be actively considering whether they have a full and accurate picture of their storm overflow assets and performance, the environmental impact of their use and “a clear and timely strategy for addressing any shortcomings in that performance”.

Christine McGourty, Water UK Chief Executive, said: “Water companies are absolutely committed to playing their part in reducing any harm from storm overflows, and that’s why they’re investing £1.1bn over the next five years on this, as part of a wider £5bn programme of environmental improvements.”

Ofwat says it will continue to work closely with the Environment Agency and Natural Resources Wales to keep abreast of their assessments of water company compliance and determine whether the findings are relevant to Ofwat's regulatory and enforcement powers.