Media Queries
Get in touch if you have queries or want to discuss our data.
press [at] top-of-the-poops.org
Please Support Us
We rely on donations to fund our work. Please support us if you can
Polluted by sewage 600 times in 2025 lasting 4,068 hours
Your local MP is David Chadwick (Liberal Democrat) - Find out more about their interests, donors, and voting at They Work For You
Please consider a one-off or small recurring donation. We need your help to keep this site going.
Donate NowHere are all the reported sewage overflow totals for Ystalyfera in 2025. Sometimes sewage can be being dumped for months at a time.
Reporting refers to how much of the time the monitoring was active. In this place all the declared CSO Combined Sewage Overflow - a device that, when operating, pours combined rainwater & sewage into a waterway s appeared to have monitoring enabled for more than 50% of the year
| Company | Waterway | Site | Sewage Dumps | Duration (Hours) | Reporting % |
|---|---|---|---|---|---|
| Dwr Cymru Welsh Water | Right Bank Of River Twrch | CSO on A4068 above Lower Brunorgan Bridge | 112 | 1,410 | 95.8 |
| Dwr Cymru Welsh Water | River Tawe | YSTRADGYNLAIS WWTW OFF WIND ROAD | 48 | 724 | 99.8 |
| Dwr Cymru Welsh Water | River Twrch | GEORGE IV CSO 23 UPPER CWMTWRCH | 45 | 315 | 99.9 |
| Dwr Cymru Welsh Water | Nant Llynfell | SWO.M'HOLE 154A GEORGE IV PH UPPER CSO | 48 | 253 | 98.8 |
| Dwr Cymru Welsh Water | River Tawe | CSO at O/S 17 Glantawe Row Ystradgynlais | 74 | 251 | 99.1 |
| Dwr Cymru Welsh Water | River Twrch | CSO 21 BRIDGE STREET | 42 | 241 | 99.9 |
| Dwr Cymru Welsh Water | River Tawe | CSO at MH 92 nr Claypon Bridge, Ystradgynlais | 35 | 214 | 99.4 |
| Dwr Cymru Welsh Water | River Tawe | CSO at Ynysmeudw Warehouse (SOC | 41 | 196 | 90.1 |
| Dwr Cymru Welsh Water | River Tawe | CSO 12 B4599 Road Bridge | 59 | 166 | 99.8 |
| Dwr Cymru Welsh Water | River Tawe | CSO at Mason Arms, Ystradgynlais | 24 | 116 | 99.4 |
| Dwr Cymru Welsh Water | River Tawe | Office Row Car Park Ystalyfera CSO | 45 | 116 | 99.9 |
| Dwr Cymru Welsh Water | River Tawe | Nr Gough Arms MH CSO | 14 | 41 | 96.7 |
| Dwr Cymru Welsh Water | River Tawe | CSO Godre'r Graig SOC 20. Godre'r | 13 | 19 | 99.9 |
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.
Get in touch if you have queries or want to discuss our data.
press [at] top-of-the-poops.org