Three major UK water companies are under suspicion for allegedly releasing sewage without rainfall, a practice termed “dry spilling,” says a BBC investigation.
Thames Water, Wessex Water, and Southern Water collectively allegedly released sewage during dry periods for approximately 3,500 hours in 2022, breaching their permits.
The BBC sought similar data from other English water companies, but they declined to respond due to ongoing criminal investigations by the Environment Agency (EA).
Sewage release into water bodies is permitted in the UK to prevent pipe systems from becoming overwhelmed, but it’s contingent on rainfall.
Water Minister Rebecca Pow said: “The volume of sewage discharged into our waters is utterly unacceptable and it’s why our Plan for Water means more investment, stronger regulation and tougher enforcement, tackling every source of pollution and ensuring swift enforcement action is taken against those who break the rules.”
A Thames Water spokesperson told Energy Live News (ELN): “There are a number of methodologies for defining and calculating why and how dry day spills occur. The EA’s methodology for calculating dry day spills is still being determined and we will continue to work with our regulators as they define this.
“We regard all discharges of untreated sewage as unacceptable, and we have planned investment in our sewage treatment works to reduce the need for untreated discharges including at Stewkley, Stone and Haddenham.
“We are the first water company to provide storm overflow alerts for inland waters and this ‘near real-time’ data is available to customers as a map on our website. We want to lead the way with this transparent approach to data and we have also published on our website our plans to upgrade over 250 of our sewage treatment works and sites.
“Stopping discharges altogether will take time and sustained investment, however each step we take on this journey is a move in the right direction.”
A Wessex Water spokesperson told ELN: “This a known issue caused by high groundwater which, unlike rainfall that stops relatively quickly, continues for days or even months. None of these overflows cause rivers to fail to meet ecological standards.
“We’re using nature-based solutions to treat groundwater-affected sites, and by 2025 we will have completed or progressed 28 schemes in our region.
“Meanwhile we’re investing £3m a month on reducing overflows, which we agree aren’t fit for the 21st century, and we’re planning to invest significantly more between 2025 and 2030 subject to regulatory approval.”
John Penicud, Head of Wastewater at Southern Water, said: “So-called ‘dry spills’ are a complex issue. Water is a powerful force of nature – and high groundwater conditions can lead to rising water finding the path of least resistance into a network of sewer pipes – ours and private – and manholes, and a discharge made up of groundwater is not caused by rainfall and can happen in dry weather. It is required to be reported as a ‘spill’.
“The problem is especially challenging in areas prone to flooding, as mitigation measures such as sewer relining and manhole sealing redirect flows and groundwater can then cause flooding. Private, illegal connections to the system are another potential source.
“We work with the EA and stakeholders to cut these so-called ‘dry spills’ – and all forms of water and wastewater releases.”
An EA spokesperson stated that they are currently conducting their largest-ever criminal investigation into potential widespread non-compliance by water and sewerage companies at numerous sewage treatment works.
The EA spokesperson added: “Our tough enforcement action has already led to over £150 million in fines since 2015. We will always pursue and prosecute companies that are deliberately obstructive or misleading – and work constructively with those driving improvements.
“We are also improving how we regulate the sector – including expanding the number of officers focused solely on regulation, increasing compliance checks and recruiting more data specialists able to translate storm overflows monitoring data into stronger regulatory intelligence”
A Water UK spokesperson told ELN: “There should be no dry spills of sewage into waterways. Ideally, there should be no spills at all. Sorting out sewage spills will take investment, which is why the industry has a £10 billion plan – triple the current amount – to upgrade the nation’s sewers.”
An Ofwat spokesperson told ELN: “Water companies’ performance on the environment is simply not good enough.
“We have pushed companies to take urgent action to cut sewage discharges and have recently announced new measures to penalise companies that fail to fully monitor their storm overflows. In addition, we can now take action against companies that pay out unearned dividends.”
