We have live data for Thames Water so we can track what happens every day - given that overflows are supposed to happen on an 'exceptional' basis only - does the chart indicate that?

How does each water company compare? These are the totals by company for each. The totals are really high, counting things in hours doesn't make it very easy to think about. Here we show how many years of continuous sewage dumps happened in a single year, by water company.

Please note: 2025 & 2026 numbers do not include Scottish Water and are estimates based on so-called 'live data' from the Water Industry.

It isn't like there are just a few outliers... the problem exists across the entire estate of water assets. Here we show a 'cumulative frequency diagram' - where the number of CSO Combined Sewage Overflow - a device that, when operating, pours combined rainwater & sewage into a waterway s that dumped sewage for a time, or longer, is shown. You can see that many CSO Combined Sewage Overflow - a device that, when operating, pours combined rainwater & sewage into a waterway s dumped sewage into a river for months and months.

Thames Water is highlighted in the plot below

These water companies are responsible for managing sewage treatment and preventing pollution in our waterways.