As the annual Oxford Cambridge Boat Race approaches this weekend, environmental campaigners have raised alarms over water quality along the River Thames. They warn that the stretch of river set to host the iconic event would be deemed ‘poor’ under official bathing water standards.
New data from environmental charity River Action shows that nearly 30% of water samples taken from the Boat Race course since 10 March have exceeded safe thresholds for E.coli contamination – almost triple the rate associated with the lowest possible bathing water classification.
Pollution persisting despite dry conditions
Typically, wet weather increases the risk of river pollution due to storm overflows. However, River Action notes that since testing began, there has been only one day of rain. Despite the dry conditions, contamination levels remain high, prompting concern about other sources of pollution—particularly treated wastewater.
Campaigners argue that current environmental laws do not require sewage treatment plants to meet any specific limits on E.coli, making them a significant yet overlooked contributor to poor water quality.
River Action’s Head of Communities, Erica Popplewell, highlighted the issue: “The Mayor of London’s vision for clean and healthy rivers is simply a pipe dream without systematic reform of the water industry and its regulators.
“Right now, if the stretch of the Thames used for the Boat Race were an official bathing site it would be graded poor, the lowest possible rating. The government’s own advice for such water is ‘do not swim.’ So, we strongly suggest that the winning team on Sunday think twice before throwing their cox in the Thames.
“We would also urge all rowers to follow the ‘Guidance for Rowing When Water Quality is Poor’ safety guidelines to mitigate risk. The Boat Race should be about sporting excellence—not about worrying if you’ll get sick from being dunked – and attracting people to take up water sports as a healthy activity.
“The public demands Thames Water and regulators act now to improve sewage treatment infrastructure. Thames Water has profited from pollution for years whilst the Government have failed to enforce the law. It’s time to refinance the company without burdening billpayers and end pollution-for-profit.
“The decades-long water industry privatisation experiment has been a disaster. Thames Water should be put into Government hands and operated for public benefit. That process could start tomorrow with the right political will by putting Thames Water into Special Administration and restructuring the company.”
Equipment failures and infrastructure woes
Adding to the controversy is the revelation that the monitoring system at the Kew Transfer combined sewage overflow – just upstream of the Boat Race finish line – has been offline since 17 January.
Thames Water data accessed via the Thames Water API and collated by the team behind Sewage Map app confirms the monitor went offline on 17 January 2025 and remained out of operation during the entire testing window (10 March to 07 April 2025. This means there is currently no data on how much untreated sewage might be entering the river at that site, a violation of regulations requiring sewage outfalls to be monitored.
Thames Water, the utility responsible for London’s wastewater, has come under intense scrutiny. Critics argue the company has failed to maintain critical infrastructure while simultaneously seeking a £3 billion bailout and awarding large bonuses to executives. Campaigners are calling for the company to be placed under Special Administration and returned to public ownership.
Voices from the rowing community
Prominent figures from the rowing world have joined the call for action. Sir Steve Redgrave, a five-time Olympic gold medallist, expressed frustration: “It’s a real worry that in 2025, unsafe water quality in the Thames is still a concern. Rowers, river users, and the public deserve better.”
Olympic champion Imogen Grant echoed his sentiments, highlighting the health and environmental risks faced by athletes training on the river. “As rowers, we train on these waters every day, and the health and climate risks are deeply concerning. It’s unacceptable that we have to compete on a river with such an unavoidable threat to health,” she said.
Event organisers respond
The Boat Race organisers have acknowledged the concerns and are working with British Rowing, The Rivers Trust, and River Action to ensure the safety of competitors. All participants have received safety guidelines for rowing in poor water quality.
Regulatory reform on the horizon?
The calls for systemic change come as the government’s Water Commission, led by Sir Jon Cunliffe, prepares to release its recommendations this summer. Campaigners are urging regulators and politicians to introduce stricter environmental standards, enforce existing laws, and consider public ownership of failing water utilities.
