Thames Water, is the UK’s largest water and wastewater company, serving over 16 million customers. Despite its breadth, it remains a privatised water company in England, with shareholders primarily based in Canada and Australia. Thames Water is regulated by Ofwat and the Environmental Agency.
In May 2025, they received the largest fine to have ever been issued by Ofwat, totaling a staggering £122.7 million. The hefty bill comprised of £104.5 million for breaching rules relating to wastewater operations, with a further £18.2 million charged for breaches of rules relating to dividend payments, though this equated to just 9% of the company’s average yearly profit.
It should come as no surprise then, that Thames Water was the worst rated and most polluting water company in England across 2024-5, being scored the lowest possible one star for its environmental performance by the regulator. While serious pollution incidents across the UK increased by 66%, Thames Water was responsible for more than half of them.
Thames Water urgently needs to stop rewarding itself for persistent failure and environmental harm and start investing in the basic infrastructure needed to protect public health and rivers.
