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  • by Karma Loveday

Defra opens the floodgates to £56bn storm overflow programme

The government has confirmed it will press ahead with the Storm Overflows Discharge Reduction Plan it consulted on in spring, with the principle targets unchanged (see summary below). The plan is designed to lead to an 80% reduction in the number of annual discharges by 2050, around 300,000 spills a year.

The plan will require the largest environmental infrastructure investment ever made by the water industry, at £56bn in capital expenditure over the 25 years from 2025-2050. Defra said annual water bills, averaged between 2025 and 2050, will eventually rise by £42 a year (no bill impacts until 2025), but this will be incremental, with £12 expected to be added to the average bill between 2025 and 2030.

There will be a very uneven burden across the country though, depending on storm overflow numbers and modelled improvement costs. Yorkshire, United Utilities and Wessex account for over three quarters of the investment required relative to their consumer base, which Defra said could boost bill impacts to three times the national average in those areas. Meanwhile bill impacts for firms with the smallest programmes are expected to be lower than a seventh of the national average.

To account for the uncertainty on cost and speed of delivery, Defra will review the plan and costings in 2027 ahead of PR29.

A Water UK spokesperson said: “This plan represents a step forward in the urgent collective mission to tackle our reliance on storm overflows and builds on the spending from water companies that’s already underway. Companies agree there is an urgent need to do more and are ready to invest to achieve these ambitious plans.

“Additional action from government, regulators and other sectors could bring greater environmental benefits. Government should close the loophole that allows housing developers the right to overload sewers and also take action on the flushed wet wipes that create the fatbergs that cause so many blockages. A greater focus on keeping rainwater out of sewers, via measures such as sustainable drainage, would also tackle the source of the problem and help bring about the transformation we all want to see.”

Meanwhile, joining the chorus of protest against raw sewage releases last week were three French MEPs concerned about seafood from the English Channel

Final discharge reduction targets

By 2050, water companies shall only be permitted to discharge from a storm overflow where they can demonstrate that there is no local adverse ecological impact. For high priority sites, this target must be met in full by 2045, and for 75%+ sites by 2035. This “will mean that no water body in England will fail to achieve good ecological status due to storm overflow discharges”.

For storm overflows discharging into and near designated bathing waters ( about 8%), water companies must significantly reduce harmful pathogens by either applying disinfection, such as with ultraviolet radiation, or reduce the frequency of discharges to meet Environment Agency spill standards by 2035 (of three or fewer discharges per bathing season, with some bathing waters having tighter limits).

Storm overflows must not discharge above an average of ten rainfall events per year by 2050.

Water companies must also ensure all storm overflows, regardless of where they discharge to, have effective screening controls and must be well maintained.


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