Top of the Poops | Waterway | River Taff | Polluted by Dwr Cymru Welsh Water

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Totals for River Taff in 2025

25 Sites polluted by Dwr Cymru Welsh Water

1,285 sewage dumps
10,234 h duration

That's 1.18 years. On average 3.5 times a day

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Constituencies along River Taff

Places along River Taff

Pollution Summary 2025

Here are all the reported sewage overflow totals for River Taff in 2025. Sometimes sewage can be being dumped for months at a time.

Company	Waterway	Site	Sewage Dumps	Duration (Hours)	Reporting %
Dwr Cymru Welsh Water	River Taff	Hermon Wastewater Treatment Works	163	2,506	94.3
Dwr Cymru Welsh Water	River Taff	CILFYNYDD STW CILFYNYDD PONTYPRID	112	1,698	97.7
Dwr Cymru Welsh Water	River Taff	Tongwynlais CSO	69	1,222	99.9
Dwr Cymru Welsh Water	River Taff	Tonteg Road, Upper Boat CSO and Pumping Station Emergency Overflow	119	851	99.9
Dwr Cymru Welsh Water	River Taff	CYNON VALLEY STW GLYNCOCH PONTY	64	778	99.9
Dwr Cymru Welsh Water	River Taff	Abercynon Wood Rd SPS	66	703	99.9
Dwr Cymru Welsh Water	River Taff	Crossbrook St CSO, Pontypridd	62	379	98.8
Dwr Cymru Welsh Water	River Taff	Cilfynydd STW Cilfynydd Pontypridd Settled Storm	20	329	99.8
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	YNYSANGHARAD PARK CSO	93	217	99.9
Dwr Cymru Welsh Water	River Taff	Quakers Yard CSO, Greenfield Victoria Bridge	32	160	86.5
Dwr Cymru Welsh Water	River Taff	Quakers Yard CSO, Fiddlers Elbow St, Cynon	32	157	99.5
Dwr Cymru Welsh Water	River Taff	Ynys Bridge CSO	32	155	98.6
Dwr Cymru Welsh Water	River Taff	Rhydfelin CSO Off Lionel Terrace	32	154	99.9
Dwr Cymru Welsh Water	River Taff	Gellideg Tai Mawr Rd CSO, Merthyr Tydfil	47	140	99.4
Dwr Cymru Welsh Water	River Taff	CASTLE INN CSO ASSET NO 32280	30	86	63.6
Dwr Cymru Welsh Water	River Taff	Pontypridd West Street CSO	63	52	99.2
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	River Taff	Troedyrhiw, Yew Street CSO	16	17	81.6
Dwr Cymru Welsh Water	River Taff	Cardiff Wood St/Havelock St Jn CSO	13	13	99.6
Dwr Cymru Welsh Water	River Taff	Park Street PS	6	4	99.9
Dwr Cymru Welsh Water	River Taff	TROEDYRHIW PS	3	4	99.8
Dwr Cymru Welsh Water	River Taff	3rd Trunk CSO South of Glan Yr Afon	8	3	97.9
Dwr Cymru Welsh Water	River Taff	CSO WILLOW GAS WORKS MERTHYR TYDFIL	0	0	98.8
Dwr Cymru Welsh Water	River Taff	Phyllis Street CSO, Troedyrhiw	0	0	0
Dwr Cymru Welsh Water	River Taff	TRUNK CSO 2A OFF ABERFAN ROAD	0	0	100
Dwr Cymru Welsh Water	River Taff	Sion Street Sewage Pumping Station	0	0	99.9
Dwr Cymru Welsh Water	River Taff	Taff St CSO, Pontypridd	0	0	99.9
Dwr Cymru Welsh Water	River Taff	YNYSANGHARAD HIGH LEVEL RELIEF CSO	0	0	97.6

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.

Analysing sewage pollution by the Water Industry

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