Analysis by The Telegraph has found that more than 60 per cent of areas of outstanding natural beauty (AONB) in England were suspected of having illegal sewage discharges last year.
Water companies are allowed to discharge sewage into UK waterways via overflow points to prevent water entering people’s homes.
However, this is only intended to happen during exceptionally heavy rainfall. Any spills that occur on dry days are potentially illegal and will be investigated by the Environment Agency.
The Telegraph’s analysis of the start and stop times of sewage overflow points at all nine English water and sewerage companies found that 22 of the 34 AONBs may have had illegal dry spills.
Holiday destinations in Cornwall and the New Forest were hit, as were popular swimming spots and habitats of rare wildlife.
It comes as Sir Keir Starmer’s government is under pressure to tackle the sewage crisis, which led to more than 450,000 leaks last year – spanning more than four million hours.
Charles Watson, director of River Action, said the figures for suspected illegal discharges showed a level of lawlessness in a broken system and called on the government to take radical action to end the practice.
“If anything were to show the extent to which our sewerage systems are broken, it would be these huge numbers of potentially illegal dry spills – an average of about 20 a day,” he said.
“And if anything were to demonstrate the environmental damage caused by this widespread abusive behaviour by the water industry, it would be the repeated pollution of the country’s most ecologically sensitive areas, including our many areas of outstanding natural beauty.”
Ash Smith, from campaign group Windrush Against Sewage Pollution, said the dry discharge figures showed the Environment Agency had allowed the problem to “get out of hand”.
“What else can they be but illegal?” he said. “The Environment Agency is a completely pathetic regulator when it comes to dealing with them.”
The Telegraph examined the start and end times of all sewage discharges in 2023, as provided by the nine English water and sewerage companies through a Freedom of Information (FoI) request.
The data from these requests was compared with weather data to find leaks that occurred during a three-day period without rain, also known as a dry leak.
In total, 881 dry spills occurred in 22 of the 34 designated areas of outstanding natural beauty in England. This can cause greater damage to the environment because the sewage is not properly diluted.
According to The Telegraph, a total of 7,508 potentially illegal dry spills occurred across all nine water supply areas in 2023.
The three-day method is more generous than the calculations used by the Environment Agency because it takes into account some draining time.
The AONB worst affected was Dorset, with 149 potential dry floods, closely followed by 147 in the North Wessex Downs, which is home to rare chalk river habitats.
Charlotte Hitchmough, director of Action for the River Kennet, which flows through the North Wessex Downs, said sewage discharges were leading to “really sad looking rivers” blocked by algal blooms.
She said the charity had received reports of children becoming ill after swimming at a popular riverside swimming spot in the village of Axford, Wilts.
“Untreated sewage undoubtedly contains things that can make you really sick,” she said. “It’s not unreasonable to expect that children can paddle in the chalk stream without getting sick.
“We’ve gotten to the point where we can’t really say it’s safe anymore, and that’s not a nice place to be.”
Residents of the historic village of Lambourn in Berks are regularly experiencing sewage in their streets, which Thames Water blames on heavy rainfall and groundwater infiltration.
The River Lambourn, after which the village and surrounding valley are named, is a Special Area of Conservation with one of the highest levels of protection due to its vital habitats.
The area is also one of the most important centres for the horse racing industry, with over 1,500 thoroughbred horses being kept there, vital to an industry that generates £4 billion a year and employs 88,000 people in the UK.
“The water came from wells in the street. There was feces and sanitary towels, it was really disgusting,” she said.
“The idea that this sewage is so diluted that nothing bad happens is not really an argument anymore. We can’t keep pretending that it’s not happening, or keep pretending that it’s a minor thing.”
Regardless of the groundwater infiltration, “it’s still illegal,” she said. “They need to change the law, or accept that it’s still illegal.”
Wessex Water was found to be the biggest polluter through dry spills in AONBs, with 295.
The water company, whose chief executive Colin Skellett last year lost his £290,000 bonus on top of his salary amid public outcry over pollution, told the Telegraph that most of the pollution was caused by high groundwater levels.
This can allow excess water to seep into the pipes if there are leaks or other access points.
But in correspondence seen by The Telegraph from 2020, EA officials clarified that “discharges of untreated sewage resulting from groundwater infiltration alone are not permitted” and said it would regulate all discharges that occur outside of storms.
According to Tessa Wardley of Rivers Trust, dry discharges increase risks to people and pets, as well as to river ecosystems.
“River discharge will likely be lower, leading to higher concentrations of pollutants and pathogens in the water,” she said.
“Our areas of outstanding natural beauty should be havens for nature and wildlife to enjoy for all. They should be prioritised for flood control measures against combined sewer flooding along our precious chalk streams and other environmentally sensitive sites, as well as bathing and shellfish waters.”
The EA is currently conducting a groundbreaking investigation into possible illegal oil spills. The EA will only investigate these if they occur within a 24-hour period without oil.
Water companies will be given the chance to explain any mitigating circumstances that may not be captured in the data provided to The Telegraph, such as an area where it may take a long time for water to be discharged into the sewer system, before the Environment Agency decides whether a licence breach has occurred.
A follow-up investigation should determine whether water companies will be fined. Enforcement will be more likely if a leak has occurred in a protected area, such as an area of exceptional natural beauty.
Campaigners say the Environment Agency is being too generous in accepting mitigating circumstances, arguing that any spill on a dry day should be considered a breach of the water company’s permits.
The government has promised to force water companies to stop discharging sewage, but has been accused of failing to take strong action against illegal activities.
The water companies, including Thames Water, disputed the methodology used by The Telegraph, which they said failed to take into account the time it takes to drain the water and the possibility of faulty equipment.
But in a statement, trade body Water UK said: “We agree that any sewage discharge is unacceptable.
“We disagree with the analysis of these data. Conclusions about dry spills can only be drawn with detailed analysis of rainfall, catchment size, shape and geology, and operational sensor data.”
Previous analysis by the BBC, using a similar methodology to that used by The Telegraph, suggested that almost 6,000 dry spills could occur in 2022.
The water company with the highest number of potentially illegal dry leaks was United Utilities, with nearly 1,600 detected. The company also had the highest number of total leaks in 2023.
Earlier this year, United Utilities was accused of illegally discharging millions of litres of raw sewage into Lake Windermere, a World Heritage site, after a telecommunications failure caused the main pumping station to fail.
United Utilities disputed the methodology and final figures used by The Telegraph in its analysis.
A Wessex Water spokesperson said: “National Landscapes (formerly AONBs) make up around 30 per cent of Wessex Water’s drainage area and are typically locations with a high water table, where rainwater is held in rock and soil for days or months before being released – usually via private drains.
“These discharges are so diluted that they resemble clear water, with minimal or no impact on the environment.”
An Environment Agency spokesman said: “We take our responsibility to protect the environment very seriously.
“All leaks are assessed to identify any non-compliance and we will always pursue companies that are deliberately disruptive or misleading – and take action if they are found to have breached the terms of their permits.
“One hundred percent of floods are now monitored, allowing us to ensure that water companies operate within their permits.
“We are also quadrupling inspections of our water companies this year, with up to 500 additional staff, and making better use of data and intelligence to inform our work and hold water companies to account.”
