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Polluted by sewage 733 times in 2025 lasting 2,401 hours
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Donate NowHere are all the reported sewage overflow totals for Merthyr Tudful 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 | Morlais Brook | A CSO AT WATERLOO HOUSE MERTHYR | 114 | 656 | 97 |
| Dwr Cymru Welsh Water | Morlais Brook | CSO at The Bont, Merthyr Tydfil | 89 | 394 | 96.3 |
| Dwr Cymru Welsh Water | Pentrebach Brook | Dixs Field CSO, Pentrebach, Merthyr | 81 | 334 | 94.6 |
| Dwr Cymru Welsh Water | River Taff | A CSO AT JACKSONS BRIDGE | 79 | 253 | 99.9 |
| Dwr Cymru Welsh Water | River Taff | CSO COLLEGE CAR PK MERTHYR TYDFIL | 56 | 251 | 94.1 |
| Dwr Cymru Welsh Water | River Taff | Gellideg Tai Mawr Rd CSO, Merthyr Tydfil | 47 | 140 | 99.4 |
| Dwr Cymru Welsh Water | Morlais Brook | CSO TREVITHICK MONUMENT MERTHYR | 69 | 127 | 98.7 |
| Dwr Cymru Welsh Water | Nant Morlais | Rocky Rd CSO Merthyr Tydfil | 61 | 88 | 91.5 |
| Dwr Cymru Welsh Water | River Taff | CSO Avenue De Clichy, Merthyr | 31 | 50 | 99.9 |
| Dwr Cymru Welsh Water | River Taff | Merthyr Tydfil Georgetown Lines Bridge CSO | 37 | 45 | 92.8 |
| Dwr Cymru Welsh Water | Goitre Brook | Goitre Lane CSO | 25 | 34 | 99 |
| Dwr Cymru Welsh Water | Taf Fechan | High St CSO, Cefn Coed | 28 | 20 | 99 |
| Dwr Cymru Welsh Water | Morlais Brook | Brewers Arms CSO, Balaclava Rd, Dowlais | 9 | 2 | 92.5 |
| Dwr Cymru Welsh Water | Morlais Brook | CSO AT DOWLAIS BALACLAVA ROAD | 4 | 1 | 100 |
| Dwr Cymru Welsh Water | Un Leading To Nant Morlais | Dowlais Market St & High St Junction | 2 | 0 | 97.1 |
| Dwr Cymru Welsh Water | Morlais Brook | Balaclava Rd CSO, Dowlais | 1 | 0 | 100 |
| Dwr Cymru Welsh Water | River Taff | CSO WILLOW GAS WORKS MERTHYR TYDFIL | 0 | 0 | 98.8 |
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.
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Get in touch if you have queries or want to discuss our data.
press [at] top-of-the-poops.org