It's a Dirty Business

Watch Channel 4's documentary about the state of the water industry, then sign the petition to bring water back to public ownership.

There were at least 374,370 "sewage spills" into rivers in 2025, lasting an almost unbelievable 2,422,201 hours

An image showing the river network in England and Wales, highlighting those polluted with sewage

Rivers Ranked for 2025

Here are the top rivers in England and Wales that had sewage overflows in 2025. As the list is grouped by company, some rivers may feature more than once, being polluted by different companies along their length.

The full list is quite long. You can access that

As there are different rivers with the same name in different parts of the country, it didn't seem sensible to group by river name alone.

The category of "river" is made by the water companies in their "Consent to Discharge with Conditions" - so although there are a number of Seas in this list, that's what they are reporting

Rank River Company Sewage Dumps Change Duration (Hours) Change
1 River Teifi Dwr Cymru Welsh Water 2,494 262 27,661 5,372
2 Unknown South West Water 3,803 990 25,408 -4,809
3 River Ouse Yorkshire Water 3,779 1,280 18,499 -7,050
4 River Calder Yorkshire Water 2,978 -395 18,184 -1,340
5 River Aire Yorkshire Water 3,112 -885 17,636 -3,555
6 River Avon Wessex Water 2,650 -2,571 14,496 -24,569
7 River Tamar South West Water 1,460 -541 13,790 -7,447
8 River Tawe Dwr Cymru Welsh Water 1,696 -477 11,834 -4,309
9 River Derwent Severn Trent Water 1,971 -704 10,811 -4,917
10 River Taff Dwr Cymru Welsh Water 1,279 -170 10,229 -1,903
11 River Don Yorkshire Water 2,489 660 10,162 -1,834
12 River Wharfe Yorkshire Water 1,476 -468 9,899 -4,900
13 Gwendraeth Fawr Dwr Cymru Welsh Water 1,148 119 9,820 2,443
14 River Trent Severn Trent Water 1,952 -1,234 9,628 -16,455
15 River Usk Dwr Cymru Welsh Water 1,313 -448 9,285 -5,458
16 River Marlais Dwr Cymru Welsh Water 575 -62 9,239 -490
17 River Irwell United Utilities 1,885 -638 9,208 -2,737
18 River Derwent United Utilities 1,016 -50 9,190 -415
19 River Rhymney Dwr Cymru Welsh Water 1,505 -443 8,915 -2,091
20 River Gwili Dwr Cymru Welsh Water 1,017 -60 8,854 -587

Data Sources & Accuracy

EDM (Event Duration Monitoring) data and Consented Discharges to Controlled Waters with Conditions from Environment Agency & Data Map Wales, and Scottish Water

Experimental derived data from Thames Water API, Some data may be missing or inaccurate. Live sewage data from Stream Water API

Uses Environment Agency rainfall data from the real-time data API (Beta) - Rainfall data is delayed by up to two days.

This website is intended to provide an accurate representation of the Environment Agency data. The data is hard to use, and thus some errors may have been made. If you find something that is incorrect, please raise an issue at the GitHub issues page and we'll endeavour to fix it quickly.

This project is not associated, approved or endorsed by any of the companies whose logos you see here.