Thames Water: Firm slammed for allowing raw sewage to seep into rare chalk stream for 'over 300 hours'

A river activist has slammed Thames Water for allowing “over 300 hours of sewage discharges” to seep into a rare chalk stream in Buckinghamshire. Paul Jennings posted on the social media platform on X, formerly known as Twitter, explaining how the River Misbourne in Buckinghamshire has seen continuous discharge from the Gerrard's Cross sewage treatment works.

Jennings also noted Amersham Balancing Tanks sewage treatment works which feeds into the River Misbourne “has not been working for months” and even today (Monday 5 February) the works are still offline on Thames Water’s live sewage map. The River Misbourne, which runs from Great Missenden in Buckinghamshire under the M25 towards north west London, is one of just 330 chalk streams in the world.

Mr Jennings said the chalk stream is “under pressure on many fronts from HS2 and sewage discharges” and “one result is sewage fungus - not nice.” Users on social media responded to his post of how fond they are of the chalk stream. Sarah Duce said: “I remember my mum talking about the Misbourne as a kid. How sad this chalk stream is now just a sewer.” While another user wrote on X: “To think they once grew watercress in the River Misbourne....”.

Other users responded saying it is “disgusting” while another said it is “an absolute outrage”. It comes after another chalk stream in Buckinghamshire was under threat from sewage discharges. A petition was started to stop Southern Water disposing waste in the River Test, in Hampshire, in villages near Stockbridge and Longparish.

The petition was created on Wednesday 24 January and since then, the water company’s chief executive Lawrence Gosden, wrote in a letter to a parish council that “it was a mistake” and the pipes, to test "readiness for an emergency" had been removed. On its website, Southern Water said: "We've listened to local councillors and other stakeholders and will not be installing overpumping to prevent homes flooding. Instead, we will rely on tankers to transport excess wastewater away to treatment works.”

On the sewage discharges into the River Misbourne, a Thames Water spokesperson said: “We regard all discharges as unacceptable and are sorry to those affected by this. We have published plans to upgrade over 250 of our sewage treatment works, including at our Gerrards Cross Sewage Treatment Works. The planned upgrades will improve our ability to treat the high volumes of incoming sewage and reduce the need for overflows during wet weather. This is expected to be completed in 2026.

“Taking action to improve the health of rivers is a key focus for us and we want to lead the way with our transparent approach to data. We’re the first company to provide live alerts for all untreated discharges throughout our region and this ‘near real-time’ data is available to customers as a map on our website and is also available through an open data platform for third parties, such as swimming and environmental groups to use.”