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Merthyr Tydfil and Aberdare was polluted by sewage 3,015 times in 2023
lasting 15,316 hours - that's 1.77 years!
- but monitoring was disabled in some locations, so could be more

© OpenStreetMap contributors
Contains OS Data © Crown copyright & database right 2021-2023
© Top of the Poops 2021-2023
✔ means we have experimental daily data since 2023
Totals for Merthyr Tydfil and Aberdare in 2023
68 Sites polluted by Dwr Cymru Welsh Water
3,015 sewage dumps
15,316 h duration
That's 1.77 years! On average 8.3 times a day
Change Over Time
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Constituencies near Merthyr Tydfil and Aberdare
Waterways in Merthyr Tydfil and Aberdare

Pollution Summary 2023

Here are all the reported sewage overflow totals for Merthyr Tydfil and Aberdare in 2023. 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 constituency 2 of the total 76 CSO locations had reporting enabled for less than half the year, of which 2 had zero reporting.

Company Waterway Site Sewage Dumps Duration (Hours) Reporting %
Dwr Cymru Welsh Water River Cynon MIKES FIELD CSO ABERAMAN 135 2,042 99.9
Dwr Cymru Welsh Water River Cynon CSO Opposite Arthurs Place Trecynon 143 1,726 99.9
Dwr Cymru Welsh Water River Cynon CSO ABERAMAN IND EST ABERAMAN 61 989 85.8
Dwr Cymru Welsh Water River Cynon Penderyn CSO - Tank In Field Raked Scre 127 949 96.3
Dwr Cymru Welsh Water River Cynon CSO At Bottom Monk Street 121 933 100
Dwr Cymru Welsh Water Taf Fechan PONTSTICILL WWTW 78 829 100
Dwr Cymru Welsh Water Taff Bargoed CSO at Bedlinog- Bowling Green 99 759 98.9
Dwr Cymru Welsh Water Morlais Brook A CSO AT WATERLOO HOUSE MERTHYR 132 752 97.2
Dwr Cymru Welsh Water River Dare A CSO AT FIELD ADJACENT TO DAVID ST 100 584 84.6
Dwr Cymru Welsh Water Pandy Brook TRELEWIS CSO - REAR OF GLYNBARGOED 125 481 95.9
Dwr Cymru Welsh Water River Cynon CSO at West Bank Of River South Of A455 Br 87 439 100
Dwr Cymru Welsh Water Morlais Brook CSO at The Bont, Merthyr Tydfil 105 430 98.4
Dwr Cymru Welsh Water Nant-Y-Derlwyn ABERDARE FORECOURT CSO LLWYDCOED 77 426 100
Dwr Cymru Welsh Water Taff CSO PONT RHUN MERTHYR TYDFIL 68 421 100
Dwr Cymru Welsh Water Aberdare Canal Pant-Y-Cerdin CSO, Aberdare 116 359 97
Dwr Cymru Welsh Water River Taff A CSO AT JACKSONS BRIDGE 99 343 100
Dwr Cymru Welsh Water Pentrebach Brook Dixs Field CSO, Pentrebach, Merthyr 88 261 97.8
Dwr Cymru Welsh Water Unnamed Leading To River Cynon Llwydcoed CSO Side of Llwydcoed Motors 66 239 99.2
Dwr Cymru Welsh Water River Cynon Cwmbach CSO - Outside Bro Deg 79 235 98.1
Dwr Cymru Welsh Water River Taff Gellideg Tai Mawr Rd CSO, Merthyr Tydfil 58 212 99.2
Dwr Cymru Welsh Water River Cynon CSO AT BOTTOM MONK STREET (Station St Aberdare) 67 202 100
Dwr Cymru Welsh Water River Taff CSO COLLEGE CAR PK MERTHYR TYDFIL 56 197 100
Dwr Cymru Welsh Water River Aman PLEASANT VIEW CSO 70 179 79.6
Dwr Cymru Welsh Water Nant Morlais Rocky Rd CSO Merthyr Tydfil 70 128 96.5
Dwr Cymru Welsh Water River Taff Quakers Yard CSO, Fiddlers Elbow St, Cynon 41 124 99
Dwr Cymru Welsh Water River Cynon Cwmbach Bro Deg Near No44 53 111 99.4
Dwr Cymru Welsh Water River Taff Quakers Yard CSO, Greenfield Victoria Bridge 22 103 40.6
Dwr Cymru Welsh Water Nant Wenallt And Then To River Cynon Forge Tip CSO Aberdare 52 89 77.2
Dwr Cymru Welsh Water Morlais Brook CSO TREVITHICK MONUMENT MERTHYR 40 76 29.5
Dwr Cymru Welsh Water To Nant Gwrangon CSO at Rhigos- Heol Pendarren 56 75 99.5
Dwr Cymru Welsh Water River Cynon CSO at Hirwaun Trenant No 66 Rear of Garden 6 51 1.4
Dwr Cymru Welsh Water River Cynon HIRWAUN - REAR OF BUTE TERRACE 28 48 99.8
Dwr Cymru Welsh Water River Cynon Aberaman Curre St CSO 28 44 99.2
Dwr Cymru Welsh Water River Cynon River Aberaman Wind St CSO Nr Mardy lodge 42 40 99.8
Dwr Cymru Welsh Water River Taff CSO Avenue De Clichy, Merthyr 27 38 100
Dwr Cymru Welsh Water River Camnant Hirwaun Wastewater Treatment Works 22 35 100
Dwr Cymru Welsh Water River Cynon Elizabeth St CSO 22 34 53.2
Dwr Cymru Welsh Water River Dare CSO Off Glan Road (St John the Baptist Church) 14 33 25.2
Dwr Cymru Welsh Water River Cynon CSO at Cwmbach Side of Police House 14 30 99.8
Dwr Cymru Welsh Water Taf Fechan High St CSO, Cefn Coed 36 25 88.2
Dwr Cymru Welsh Water River Cynon ABERNANT RUGBY CLUB CSO 29 23 100
Dwr Cymru Welsh Water River Cynon Canal Rd CSO, Cwmbach 9 22 99.7
Dwr Cymru Welsh Water River Cynon CSO at Rear of No12 Bonhaul, Cwmbach 8 20 99.9
Dwr Cymru Welsh Water River Cynon Cwmbach Sion Terrace No 11 CSO 13 19 99.7
Dwr Cymru Welsh Water River Cynon Penywaun - Rear Of 37/39 Erw L 27 17 96.7
Dwr Cymru Welsh Water River Taff Phyllis Street CSO, Troedyrhiw 34 16 92.9
Dwr Cymru Welsh Water River Taff Merthyr Tydfil Georgetown Lines Bridge CSO 29 15 99.9
Dwr Cymru Welsh Water Goitre Brook Goitre Lane CSO 18 14 99.2
Dwr Cymru Welsh Water River Cynon Cwmbach SPS 7 13 99.8
Dwr Cymru Welsh Water River Aman Incline Row CSO, Aberaman 7 11 100
Dwr Cymru Welsh Water Aman R - Source To Conf River Cynon Aberaman Park Industrial Estate CSO, Aberdare 5 7 99.7
Dwr Cymru Welsh Water River Cynon CSO at Aberaman 8 7 99.6
Dwr Cymru Welsh Water Morlais Brook Brewers Arms CSO, Balaclava Rd, Dowlais 18 7 94.2
Dwr Cymru Welsh Water River Cynon No. 29 Maeshyfryd CSO, Cwmbach 13 6 100
Dwr Cymru Welsh Water River Taff Troedyrhiw, Yew Street CSO 5 6 83.1
Dwr Cymru Welsh Water River Cynon Abercwmboi Parkview Capcoch Infant School CSO 6 4 100
Dwr Cymru Welsh Water Gadlys Feeder GLADLYS TUDOR TERRACE CSO 15 4 99.9
Dwr Cymru Welsh Water River Taff TROEDYRHIW PS 4 4 98.5
Dwr Cymru Welsh Water Un Leading To Nant Morlais Dowlais Market St & High St Junction 12 3 59.5
Dwr Cymru Welsh Water River Cynon No 1 Wellington St CSO, Robertstown 4 1 88.3
Dwr Cymru Welsh Water Unnamed Leading To Aman River Aberaman Cynon St rear of 3 1 100
Dwr Cymru Welsh Water River Aman CSO at Junction of David St & Pant Rd, Aberaman 1 1 53
Dwr Cymru Welsh Water Morlais Brook CSO AT DOWLAIS BALACLAVA ROAD 3 0 100
Dwr Cymru Welsh Water River Taff 3rd Trunk CSO South of Glan Yr Afon 2 0 100
Dwr Cymru Welsh Water Aman R - Source To Conf River Cynon Fforchaman Street CSO 2 0 100
Dwr Cymru Welsh Water River Cynon CSO at Rear Of St Winifreds Church Hirwa 1 0 100
Dwr Cymru Welsh Water Nant-Y-Derlwyn Trecynon, Harriet St CSO 1 0 57.3
Dwr Cymru Welsh Water Bargoed Taf CSO at QUAKERS YARD - NEAR PUBLIC HOU 1 0 99.3
Dwr Cymru Welsh Water River Cynon CSO at Hirwaun Trenant No70 Rear of Garden 0 0 0
Dwr Cymru Welsh Water River Cynon CSO at Cwmbach Bryngolwg No 45 0 0 70
Dwr Cymru Welsh Water Nant Gwawr CSO at No20 Glancynon Terrace, Aberaman 0 0 41
Dwr Cymru Welsh Water Unnamed Stream And Thence To River Cynon CSO at HIRWAUN - ON TRAMWAY 0 0 77.2
Dwr Cymru Welsh Water Morlais Brook Balaclava Rd CSO, Dowlais 0 0 100
Dwr Cymru Welsh Water River Aman CSO at Aberaman Cardiff Road No 104 0 0 12.3
Dwr Cymru Welsh Water River Taff TRUNK CSO 2A OFF ABERFAN ROAD 0 0 100
Dwr Cymru Welsh Water River Taff CSO WILLOW GAS WORKS MERTHYR TYDFIL 0 0 0

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. This 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.

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