Sewage Discharges: England and Wales’ 2025 Annual Summary Data released

According to today's data:

• Raw sewage was discharged into England’s rivers for over 1.8 million hours (1,873,751), a total of 291,492 times in 2025. This is a 35% decrease in total hours, and 48% decrease in total number of discharges.

• Raw sewage was discharged into Wales rivers for 777,545 hours, a total of 94,974 times in 2025. This is a 17% decrease in total hours, and 16% decrease in total number of discharges.

To see the breakdown by water company, scroll to the bottom of this page.

Raw sewage is a key polluter of rivers, contributing to many stretches failing their health assessments. It contains excrement, sanitary products and pharmaceuticals, and is mixed with rainwater (which can contain its own cocktail of toxic chemicals) before being released into rivers through Combined Sewer Overflows (CSOs) instead of reaching a sewage treatment plant.

Is the situation getting better or worse?

In total, this is less than the number of hours reported in 2024. But, that’s far from the whole picture.

2025 was a significantly drier year - especially in the North, Midlands and the East. In fact, every region in Scotland, Wales and England was drier in 2025 than the previous 12 months. Several regions, including Yorkshire, North West England, Midlands, and parts of Sussex, were declared in a state of drought during the summer months, and water levels in many rivers were very low. Raw sewage is only supposed to be released into rivers during heavy rains, so we’d expect fewer discharges to have occurred. ‘Dry spilling’ is an illegal practice.

The low flows make the impact of sewage on rivers even worse. With less water in the river to dilute any sewage that entered, these already-stressed ecosystems and aquatic life are exposed to even higher pollution concentrations. At the same time, more people will be taking to rivers and seas to cool down on hot days, putting public health directly at risk.

2025 was the first year with live data

Water companies in England and Wales have to share real-time CSO alerts for sewage dumps starting and ending – something that The Rivers Trust has campaigned hard for over the past decade. While the live Welsh data sources aren’t yet available to us, we integrated the live data for England and Scotland into our Sewage Map – adding a new ‘real-time alerts’ tab.

Live alerts are important for helping communities understand potential risks and pollution in real-time, as well as helping identify key polluters, misconnected systems and dry spills (something the annual data doesn’t show).

But the live data is really, really poor quality

Our experts have spotted differences between the live data and the annual summaries reported by water companies. We receive event duration data – the time a CSO begins to discharge, and the time that it stops. There’s no way to tell the volume of water or sewage being released during those points. On some occasions the monitors, which are located at each CSO, get triggered incorrectly – for example if wildlife or weather triggers the sensor – but because the live alert is sent in real-time, it’s not manually verified. It’s also inconsistent – sometimes we receive a stop signal without a previous start signal, or a stop signal never comes.

If you add up all of the year’s live discharge event alerts, and count the time these signals indicate discharging has taken place for, the totals are very different from the annual summary data reported by water companies today. Our technical experts have identified stop and start times that have been edited, and some entire discharge events removed – all without explanation. To restore rivers and fix the system, it is essential that water companies are transparent about why the data is edited, so that we can have confidence in the information we’re being presented with.

What do you know about treated sewage?

Did you know, it’s not just raw sewage that’s a problem for our rivers? In fact, treated sewage also poses a huge threat – in some cases, causing even more damage. That’s not to diminish the problems caused by raw sewage, but to emphasize how dangerous even what comes out the other end of treatment plants can be. Treated sewage can still contain myriad chemicals, pharmaceuticals and dangerous bacteria such as E.coli, and the nature of treated sewage is that it can be almost continuously discharged, presenting a chronic problem for rivers and wildlife.

Hear more from the experts

To learn more about sewage treatment, listen to our Rambling About Rivers podcast episode about sewage pollution in rivers, which includes an interview with The Rivers Trust’s Simon Browning. Listen on Spotify or Apple Podcasts.

Breakdown by Water Company:

Our experts are cleaning up this data and will add it to the Sewage Map Annual Summaries tab in the coming days.