England’s Chalk Streams Under Threat from Sewage Pollution

England’s chalk streams, often described as the nation’s "rainforests" for their ecological richness and rarity, are facing a serious and growing threat: untreated sewage.

These unique rivers—clear, cool, and nutrient-rich—support an abundance of wildlife, including trout, salmon, kingfishers, otters, and a host of aquatic plants and invertebrates. Globally rare, around 85% of the world’s chalk streams are located in England. Yet, despite their ecological importance, these habitats are increasingly being polluted by raw sewage, discharged directly into their waters.

Sewage Overflow: A Legal Loophole Exploited

Water companies in England are legally permitted to release untreated sewage into rivers during periods of heavy rainfall, when treatment systems risk becoming overwhelmed. Known as combined sewer overflows (CSOs), these discharges are meant to be a rare emergency measure.

However, data shows this system is being overused. For example, Thames Water discharged sewage into the River Chess 96 times by mid-2021. Nationally, the situation is even more alarming: in 2020 alone, over 403,000 sewage discharge events were recorded—up 37% from the previous year.

Infrastructure Neglect and Shareholder Profits

Critics argue that the widespread pollution is the result of chronic underinvestment in sewage infrastructure. Since privatisation, water companies have reportedly paid out more than £60 billion in dividends to shareholders, while environmental performance continues to suffer. Campaigners say that, rather than reinvesting in system upgrades, companies have prioritised profit over public and ecological health.

Industry Promises and Public Concern

In response to mounting pressure, water companies have pledged billions in investment to improve wastewater infrastructure and better protect rivers. Thames Water, for example, has committed to increasing sewage treatment capacity by nearly 40% and is working with local groups to safeguard catchments feeding chalk streams.

However, environmental organisations and local campaigners argue that these promises are not enough—and that meaningful improvements remain to be seen on the ground. They are calling for stronger regulation and enforcement, and for chalk streams to receive the protections they urgently need.

A Call to Action

As the climate crisis intensifies and population growth increases demand on water systems, the health of England’s rivers hangs in the balance. Chalk streams, among the rarest freshwater ecosystems on the planet, are rapidly becoming casualties of mismanagement and regulatory failure.

With greater awareness, public pressure, and investment in sustainable infrastructure, there is still hope that these rivers can be preserved for future generations. But the window for action is narrowing.