Stock image of waste water treatment works, seen from above

The Rivers Trust Sewage Map: annual data is no longer good enough

We’ve added near real-time data to our Sewage Map, but only one water company has released suitable data. All water companies must now share real-time discharge data with the public.

Rebecca Duncan


We've added a layer showing near-real time alerts of raw sewage discharges to our interactive Sewage Map and are now calling for all water companies to make that real-time data publicly available. The layer shows which combined sewer overflows (CSOs) are discharging at any given moment, as well as those that have discharged within the last 48 hours. However, only data from Thames Water is currently available .

Thanks to a late push from environmental campaigners, the 2021 Environment Act stipulated that all English water companies must publish real-time alerts of sewage discharges into waterways, but it didn’t include a deadline for doing so. Currently, the only water company to have shared live data in a widely accessible format is Thames Water.

Technical Director David Johnson said: “We’ve seen the power of open data in recent years as people have woken up to the reality of sewage pollution, but annual summaries are no longer good enough. In the interests of transparency, we’re calling on all water companies to urgently provide real-time data on sewage discharges. This will not only allow the public to make informed decisions about safe river recreation, but also will help those of us working in the water sector understand how the sewerage system is being managed.”

Seeing when sewage discharges are happening rather than just annual summary numbers would allow for comparisons against things like weather and groundwater conditions, which are often cited as reasons for combined sewer overflows being used so regularly. It would also add to an evidence base that drives the large suite of investment in the sewage and waste water system that was brought forward in the government’s recently announced Plan for Water.

Director of Communications & Advocacy Tessa Wardley added: “It’s clear that sewage pollution has become an issue close to people’s hearts. It is having a detrimental impact on our precious river environments and is even affecting how people vote across the country. If politicians are serious about tackling the issue and water companies are serious about regaining public trust, we need to have full transparency on when CSOs are being used - real-time data gives us that, it needs to be published and in a format that we can interrogate as a matter of urgency.”

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