More than 384,000 discharges of raw sewage were reported by water companies across England and Wales in 2022, official figures show, in what the Rivers Trust has described as “extremely bad news for environmental and human health”.
However, the true scale may be even greater, as a new legal challenge has claimed. Meanwhile, another set of water firms are under investigation by the regulator Ofwat and the Environment Agency for alleged illegal dumping of sewage from treatment works, and an independent watchdog is now saying that the government and even the regulators themselves may have broken the law by letting firms discharge raw sewage more often than law allows.
As the inquiry continues, exclusive data seen by the Guardian reveals how one company, Thames Water, appears to be dumping raw sewage outside the permitted conditions at two of its sites. Dumping outside these conditions – for example, in dry weather – is a breach of the regulations and the discharges are considered to be illegal.
The charts and maps below show how much recorded sewage has been released in English and Welsh rivers in the past year, what the impact of this is and whether dumps at four sites in England met legal requirements.
A spokesperson for the Rivers Trust said: “Spilling raw sewage into rivers is extremely bad news for environmental and human health, sending all sorts of unpleasant substances into waterways that shouldn’t be there. As well as bacteria, such as E coli, anything that goes down the drain in our combined sewer system, could end up in rivers, so that includes excess nutrients like nitrogen and phosphorus, forever chemicals commonly found in household items, and microplastic particles, which are now ubiquitous in our environment.
“If these discharges are happening when minimum volumes at treatment works are not being met, or when river levels are low, these pollutants will be even more concentrated in the water, allowing algae to proliferate and meaning plant and animal life won’t have enough oxygen to survive. The current situation is absolutely unacceptable and will get even worse if investment doesn’t go into our grey and green-blue infrastructure.”
Grey infrastructure refers to human-made structures such as dams, pipes and water treatment plants. Green-blue infrastructure is a network of natural and semi-natural features designed to deliver societal benefits, such as flood protection and climate regulation.
A Thames Water spokesperson said: “Thames Water Utilities Limited is aware of a claim threatened by Prof Carolyn Roberts. Thames Water Utilities Limited has engaged cooperatively with Prof Roberts to explain that the threatened claim is without merit and no claim has yet been issued against Thames.
“We believe it is unacceptable for untreated sewage to enter rivers and we take this matter very seriously. We’ve published an action plan to radically improve our position in order to protect and improve the environment.
“We’ve recently published plans to upgrade over 250 of our sewage treatment works and sites and we have planned substantial investment in our local sewage treatment works to reduce the need for untreated discharges, including South Leigh, Stanton Harcourt and Oxford. We have also started the £100m upgrade of our Mogden sewage treatment works.
“Addressing discharges will take time and sustained investment, however each step we take on this journey is a move in the right direction.”
A United Utilities spokesperson said of the lawsuit and the wider issue of spilling: “With the largest combined sewer network in the UK and highest levels of rainfall, we are planning the biggest programme of storm overflow reduction in the country. By 2030 we will have invested £3bn to tackle the issue, with more to follow.”
A spokesperson for Dŵr Cymru (Welsh Water), who reiterated that the company was not part of the legal action, said: “We absolutely understand and accept public concern about any sewage pollution impacting our rivers and so improving river water quality is our absolute priority.
“The total removal of storm overflows from our system is currently unaffordable and would take decades but what is in our control is the ability to target investment to storm overflows which have the biggest impact on river water quality so that we can improve their performance. That is why we are investing significantly to improve storm overflows, with £140m being invested between 2020-25 with a further £420m planned from 2025 to 2030.
“We have been working in the river catchment at Pontyrhyl and Llangeinor and have discovered points where river water is finding its way into the sewer. Work is ongoing to remove this, which will have a material effect on spill numbers.
“Many different factors contribute to river and sea water quality – of which wastewater is one element. We have a strong environmental record and have invested heavily to improve water quality in both our rivers and seas. This has delivered real improvements and helped ensure that 44% of our rivers meet good ecological status compared to 14% in England, and that Wales has over a third of the UK’s Blue Flag beaches while only having 15% of the coastline.”
On the lawsuit and the wider issue of spilling, a Yorkshire Water spokesperson said: “We are aware of an alleged claim being pursued by Leigh Day solicitors. Given the nature of the proposed proceedings, it would be inappropriate for us to comment any further.”
In response to the class action legal claim, a Severn Trent spokesperson said: “This is a highly speculative claim with no merit which we strongly refute. Should pollutions ever occur, they are always reported to the Environment Agency. Any claim to the contrary is wholly and completely wrong.
“Our regulators, the Environment Agency and Ofwat, set strict targets and performance measures that deliver for our customers and the environment. Severn Trent is recognised as a sector leader by both regulators across operational and environmental measures. We consistently deliver for our customers, and recently received the highest 4* status for environmental performance from the Environment Agency for the fourth year running.”
Anglian Water and Northumbrian Water were approached for comment but declined to make a statement.
Methodology
Data on the total spilling duration of different treatment works was compiled by the Rivers Trust. Figures for England were sourced from the Environment Agency, and data for Wales was provided by Dŵr Cymru.
Data on the four wastewater treatment works in the Thames River basin was sourced from environmental information regulation requests. These are four selected treatment works out of more than 350 operated by Thames Water. All four had previously been accused of spilling outside permitted criteria, and are by no means a representative sample of all wastewater treatments works.
Data on the ecological status of rivers was sourced from the Environment Agency for England and Natural Resources Wales for Wales. Note that ecological status is not the same as overall water quality. We use ecological status as a proxy for water quality because overall water quality cannot be directly compared between England and Wales. The overall quality is determined by combining a water body’s ecological and chemical status.
