Polluted by sewage 1,721 hours in 2025
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We get information about overflowing CSOs since January 2025. Here is a chart of the last three months of data for Cardiff North, here you can see overflows in red, the darker the red, the more the CSO overflowed that day.
Each CSO has a row, the most recent data is on the right hand side.
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Donate Now| Company | Site Name | Receiving Waterway | Overflow Days | Total Duration (hours) | Total Duration (days) |
|---|---|---|---|---|---|
| Dwr Cymru Welsh Water | Tongwynlais Recreation Ground Storm Overflow | River Taff | 65 | 1,161 h 15m | 48.38 |
| Dwr Cymru Welsh Water | Began Road Cardiff Storm Overflow No2 | River Rhymni | 69 | 377 h 40m | 15.71 |
| Dwr Cymru Welsh Water | Ynys Bridge 2 Storm Overflow | River Taff | 21 | 111 h 29m | 4.62 |
| Dwr Cymru Welsh Water | Parc Caedelyn Storm Overflow | Rhydwaedlyd Brook | 19 | 21 h 23m | 0.88 |
| Dwr Cymru Welsh Water | Began Road Cardiff Storm Overflow | Rhymney | 5 | 18 h 24m | 0.75 |
| Dwr Cymru Welsh Water | Heathwood Road Storm Overflow | Nant Y Wedal | 17 | 17 h 29m | 0.71 |
| Dwr Cymru Welsh Water | Westbourne Crescent Bottom Cardiff Storm Overflow | River Taff | 9 | 10 h 56m | 0.42 |
| Dwr Cymru Welsh Water | Heol Amlwch Storm Overflow | River Taff via culverted watercourse | 5 | 2 h 56m | 0.08 |
| Dwr Cymru Welsh Water | St. Mellons Bridge Road Storm Overflow | River Rhymni | 1 | 0 h 15m | 0 |
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.