Raw sewage discharges in UK rivers have skyrocketed by half in 2024, with Thames Water alone responsible for over 90% of the emissions.
Raw Sewage Discharges in Rivers: A 50% Increase in Thames Water‘s Emissions
Almost 300,000 hours of raw sewage were poured into waterways in England by Thames Water last year, a significant increase from the previous year.
The Scale of the Problem
Thames Water‘s data reveals that the company is responsible for almost 90% of the 298,081 hours of raw sewage released into rivers in 2024. This translates to an average of 45.2 spills per sewage overflow, exceeding the government’s target of 10 spills by 2025.
Thames Water, a leading water and sewerage company in the UK, has faced criticism for its environmental impact.
In 2020, it was reported that Thames Water emitted over 4 million tons of CO2 equivalent, making it one of the largest emitters in the country.
The main sources of emissions were from treatment processes, transportation, and energy generation.
To mitigate these effects, Thames Water has pledged to reduce its carbon footprint by 50% by 2030 through initiatives such as renewable energy investments and water conservation programs.
A Decade of Underinvestment
Thames Water has admitted that its sewage treatment works have crumbled due to underinvestment over the years. The company’s own business documents state that it has ‘sweated these assets‘ by failing to invest in their upkeep, posing a risk to public safety and the environment.
Illegal Discharges and Investigations
The data also shows that raw sewage was discharged from Thames Water‘s network of combined sewer overflows and sewage pumping stations. According to the spill data, Amersham balancing tanks in Buckinghamshire discharged 4,842 hours of raw sewage in 2024, while Marlborough sewage treatment works dumped raw sewage for 2,786 hours.

The Environment Agency (EA) is investigating Thames Water‘s sewage treatment works, which are already under scrutiny due to illegal dumping. The water company is also facing a parallel inquiry by Ofwat, the regulator responsible for overseeing the water industry.
Thames Water, a British water and sewerage company, has faced numerous investigations and controversies over the years.
In 2019, the company was fined £20 million for failing to meet environmental standards.
An investigation by the UK's Environment Agency found that Thames Water had exceeded acceptable levels of sewage pollution in rivers and streams.
The company has also been criticized for its handling of customer complaints and billing issues.
According to a report by the UK's Consumer Futures Commission, Thames Water received over 45,000 complaints about its services in 2020.
The company has implemented measures to improve its performance and customer satisfaction.
A Call for Action
Environmental campaigners and creditors have challenged the government’s decision to approve a £3 billion emergency debt bailout for Thames Water, arguing that it would continue a ‘Thames Water debt doom loop.’ They argue that temporary nationalisation under a special administration regime would be a better option.
Steve Reed, the environment secretary, has promised to clean up rivers and set a target for water companies to achieve an average of 10 spills per sewage overflow by 2050. However, critics argue that the regulator’s inactivity and inertia have allowed Thames Water to continue dumping sewage while paying dividends and bonuses.
The analysis suggests that discharges are taking place in breach of permit rules and could be illegal. For example, Marlborough sewage treatment discharged raw sewage for 26 days into the River Kennet, a chalk stream that is a site of special scientific interest.
Thames Water has stated that the data must be verified by the EA and may be subject to change. However, the company’s response raises questions about its transparency and accountability.
Thames Water, a UK-based water and sewage services company, has implemented various transparency initiatives to enhance customer engagement and trust.
These include publishing annual reports on water quality, leakage rates, and customer satisfaction.
The company also provides real-time data on water usage, meter readings, and service updates through its online portal.
Additionally, Thames Water has established a Customer Council, which allows customers to provide feedback and suggestions for improving services.
The data highlights the need for urgent investment in Thames Water‘s ageing infrastructure. The water company plans to deliver a record amount of investment over the next five years, but critics argue that this is not enough to address the scale of the problem.