Eighteen sites on the River Thames in Oxford and its upstream tributaries will be tested today to investigate whether the city could host the UK’s second ever designated river bathing water.

The Oxford WaterBlitz is part of the Oxford Rivers Project, the UK’s longest and largest study of bacterial water quality in rivers, and will see trained volunteers take samples from the river to establish a snapshot of the levels of pollution from sewage, agriculture, and other domestic or commercial sources. Regular testing of the sites began in April as part of the End Sewage Pollution Mid-Thames Group’s campaign for Port Meadow to become a designated bathing water, but this is the first time all sites will be tested in one day.

The results collected by citizen scientists will be processed in Thames Water laboratories and analysed by data scientists from The Rivers Trust to give a clearer picture of how safe the site currently is for recreational use. The results are set to be published in late June, followed by a more detailed report in the Autumn.

Sewage pollution has been highlighted as a major problem for rivers, particularly in the past year. In the upper Thames, untreated sewage was released for 50,000 hours in 2020, carrying bacteria which can be harmful to swimmers, kayakers and other river users. Until this year, bacterial water quality was not tested in the region, as these tests are only required for designated bathing water sites.

Last year, more than 5,000 residents signed a petition calling for a designated bathing water area in Oxford, regular testing for bacteria, alerts of raw sewage spills, and improvements to the wastewater system.

Oxford City Council unanimously supported the aims of the petition, and after a meeting with Sarah Bentley, CEO of Thames Water, the Oxford Rivers Project was launched: a partnership between the #endsewagepollution mid-Thames campaign group, Oxford City Council, the Rivers Trust, Thames Water, and Thames21, which is hosting the Project.

If the application is successful, the public will be able to access real-time water quality data throughout the official outdoor bathing season, which runs from May to September. In April, Thames Water agreed to issue alerts when sewage discharges into the mid-Thames occur in support of the bathing water application. It is hoped that the designation would spur a wider clean-up of the Thames in the Oxford region.

Thames Water, along with other water companies, is publishing annual EDM (event duration monitor) data online, and areas with designated bathing water status which were receiving seasonal notifications can now expect to see alerts shared throughout the year.

Debbie Leach, CEO of Thames21, said: “Thames21’s recent appearance on Panorama helped to highlight the huge problem of sewage pollution in rivers. The Oxford Rivers Project is a fantastic community-led initiative that shows how people can make a real difference and we are delighted to support it. The Council’s application for Bathing Water Status is a crucial opportunity that will give the rivers at Oxford the same public health testing as our seaside and ensure that it is safe to swim in. We need clean water in our rivers.”

Mark Lloyd, CEO of The Rivers Trust, said: “Following the science is absolutely crucial if we’re going to restore our rivers, and the overall environment, to good health, so it is very exciting to be engaging the public in this landmark citizen science initiative. We’re very hopeful that there will be many more projects like this across the country, so our waterways can thrive again for people and wildlife.”

Sarah Bentley, Thames Water CEO, said: “Our aim will always be to try and do the right thing for our rivers and for the communities who love and value them. We’re pleased to be working with local partners such as Thames21 and actively listening to our customers, who have clearly told us to do more to protect these incredible environments.

“We have substantial planned investment in our local sewer network and will also be upgrading sewage treatment works, including for example a major expansion at Witney in Oxfordshire.”