It's a Dirty Business

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Cardiff West - 2025 Sewage

Polluted by sewage 3,976 hours in 2025

© OpenStreetMap contributors
Contains OS Data © Crown copyright & database right 2021-2024
© Top of the Poops 2021-2024

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View Annual Sewage Data

You're looking at the totals that we have calculated for sewage in Cardiff West for 2025. It is an estimate, based on very poor quality live data from the Water Companies. This may not align with the 'official' reported sewage values from the water companies, which is reported in April following then end of the year - so 2025 numbers are reported in April 2026.

What's a potential overflow? If the CSO goes 'Offline' while its Overflowing, we don't know if it stopped overflowing until we get a 'Stop' event.

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Daily Data

Jan - 0 hours
Feb - 340 hours
Mar - 38 hours
Apr - 251 hours
May - 21 hours
Jun - 37 hours
Jul - 8 hours
Aug - 9 hours
Sept - 500 hours
Oct - 297 hours
Nov - 995 hours
Dec - 1,474 hours
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Thank you so much to everyone who contributed to the site in 2025 to keep it running. We do rely on your contributions! Developing and running a website costs real money.
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Totals so far

Company Site Name Receiving Waterway Overflow Days Total Duration (hours) Offline/Potential Pollution
Dwr Cymru Welsh Water Rhiwsaeson WwTW Storm Overflow River Clun 118 1,162 h 44m -
Dwr Cymru Welsh Water Creigiau WwTW Storm Overflow The Nant Glaswg 62 1,062 h -
Dwr Cymru Welsh Water Groesfaen Storm Overflow Nant Coslech 66 592 h 30m -
Dwr Cymru Welsh Water St Fagans Storm Overflow River Ely 53 443 h 52m -
Dwr Cymru Welsh Water Rhydlafar WwTW Storm Overflow Nant Dowlais 68 268 h 52m -
Dwr Cymru Welsh Water Llys Tripp Gwaelod-Y-Garth Overflow River Taff 66 178 h 39m -
Dwr Cymru Welsh Water Miskin Railway Storm Overflow River Ely 17 89 h 41m -
Dwr Cymru Welsh Water Trelai Park Storm Overflow River Ely 23 67 h 37m -
Dwr Cymru Welsh Water Ffordd Dinefwr PS Storm Overflow Tributary of Nant Henstaff 19 46 h 31m -
Dwr Cymru Welsh Water Brynsadler Storm Overflow River Ely 9 21 h 15m -
Dwr Cymru Welsh Water Unknown Unknown 7 12 h 49m -
Dwr Cymru Welsh Water Ynysddu Storm Overflow River Ely 10 11 h 19m -
Dwr Cymru Welsh Water Mill Road 1 Storm Overflow River Ely 13 7 h 33m -
Dwr Cymru Welsh Water Dan-y-Bryn Storm Overflow River Ely 8 6 h -
Dwr Cymru Welsh Water Plymouth Wood Road Storm Overflow River Ely 6 2 h 57m -
Dwr Cymru Welsh Water Penally Road Ely Cardiff Overflow River Ely 3 2 h 14m -
Dwr Cymru Welsh Water Rhyd-Y-Nant Storm Overflow River Ely 0 0 h -
Dwr Cymru Welsh Water Bishopston Rd Cardiff Overflow River Ely 0 0 h -
Dwr Cymru Welsh Water Fairview Storm Overflow River Ely 0 0 h -

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.