Cynon Valley polluted by sewage 2,967 times in 2023 - lasting 19,940 hours
- 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 Cynon Valley in 2023
59 Sites polluted by Dwr Cymru Welsh Water
2,967 sewage dumps
19,940 h duration
That's 2.31 years! On average 8.1 times a day
Change Over Time

Pollution Summary 2023

Here are all the reported sewage overflow totals for Cynon Valley 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 70 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 Taff Settled Storm at Cynon Valley Wastewater Treatment Works 167 2,789 99.8
Dwr Cymru Welsh Water River Taff Cilfynydd STW Cilfynydd Pontypridd Settled Storm 146 2,461 100
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 PONTCYNON PIPE BRIDGE CSO ABERCYNON 110 1,127 96.7
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 Nant Clydach Tank Near Pit CSO Ynysybwl 135 882 98.4
Dwr Cymru Welsh Water River Dare A CSO AT FIELD ADJACENT TO DAVID ST 100 584 84.6
Dwr Cymru Welsh Water Nant Clydach GLYN STREET CSO GLYN ST YNYSYBWL 117 558 98.6
Dwr Cymru Welsh Water River Taff Abercynon Wood Rd SPS 79 511 100
Dwr Cymru Welsh Water River Cynon CSO at West Bank Of River South Of A455 Br 87 439 100
Dwr Cymru Welsh Water Nant-Y-Derlwyn ABERDARE FORECOURT CSO LLWYDCOED 77 426 100
Dwr Cymru Welsh Water River Cynon CSO Opposite Miskin Hotel, far side of railway 102 425 98.9
Dwr Cymru Welsh Water River Cynon Oxford St CSO, Mountain Ash 69 409 49.4
Dwr Cymru Welsh Water Aberdare Canal Pant-Y-Cerdin CSO, Aberdare 116 359 97
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 Cynon CSO AT BOTTOM MONK STREET (Station St Aberdare) 67 202 100
Dwr Cymru Welsh Water River Aman PLEASANT VIEW CSO 70 179 79.6
Dwr Cymru Welsh Water Nant Clydach CSO at Clydach Rd, Ynysbwl 44 163 82.8
Dwr Cymru Welsh Water River Cynon Glassbrook Terrace CSO, Penrhiwceiber 57 132 99.3
Dwr Cymru Welsh Water River Cynon Cwmbach Bro Deg Near No44 53 111 99.4
Dwr Cymru Welsh Water River Cynon Duffryn Rd Mount 2 CSO 32 96 99.8
Dwr Cymru Welsh Water Nant Clydach CSO O/S 2 Clydach Terrace, Ynysybwl 25 90 81.5
Dwr Cymru Welsh Water Nant Wenallt And Then To River Cynon Forge Tip CSO Aberdare 52 89 77.2
Dwr Cymru Welsh Water To Nant Gwrangon CSO at Rhigos- Heol Pendarren 56 75 99.5
Dwr Cymru Welsh Water River Cynon Penrhiwceiber Point D CSO 49 70 99.6
Dwr Cymru Welsh Water River Cynon NEWTOWN COMMUNITY HALL CSO 34 63 99.7
Dwr Cymru Welsh Water River Cynon CSO at Hirwaun Trenant No 66 Rear of Garden 6 51 1.4
Dwr Cymru Welsh Water R Cynon - Conf Aman R To Conf R Taff Station Terrace CSO, Penrhiwceiber 32 49 85.7
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 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 Nant Clydach Old Parish Road CSO, Ynysbwl 16 30 16.3
Dwr Cymru Welsh Water River Cynon CSO at Cwmbach Side of Police House 14 30 99.8
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 Nant Cae-Dudwg End of Park Place CSO, Cilfynydd 8 17 99.8
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 River Cynon No. 29 Maeshyfryd CSO, Cwmbach 13 6 100
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 Cynon No 1 Wellington St CSO, Robertstown 4 1 88.3
Dwr Cymru Welsh Water River Aman CSO at Junction of David St & Pant Rd, Aberaman 1 1 53
Dwr Cymru Welsh Water Unnamed Leading To Aman River Aberaman Cynon St rear of 3 1 100
Dwr Cymru Welsh Water River Cynon CSO at Rear Of St Winifreds Church Hirwa 1 0 100
Dwr Cymru Welsh Water Aman R - Source To Conf River Cynon Fforchaman Street CSO 2 0 100
Dwr Cymru Welsh Water Nant-Y-Derlwyn Trecynon, Harriet St CSO 1 0 57.3
Dwr Cymru Welsh Water River Cynon Cwmpennar CSO, Adj Low Rd, Mountain Ash 0 0 9.2
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 Nant Cae-Dudwg PARK PLACE CSO 0 0 100
Dwr Cymru Welsh Water River Cynon Abercynon Rugby Club CSO 0 0 99.5
Dwr Cymru Welsh Water River Cynon CSO at Hirwaun Trenant No70 Rear of Garden 0 0 0
Dwr Cymru Welsh Water River Aman CSO at Aberaman Cardiff Road No 104 0 0 12.3
Dwr Cymru Welsh Water Unnamed Stream And Thence To River Cynon CSO at HIRWAUN - ON TRAMWAY 0 0 77.2
Dwr Cymru Welsh Water River Cynon No 10 Hamilton St CSO, Mountain Ash 0 0 40.7
Dwr Cymru Welsh Water Culvert NEW ROAD SEWERAGE SYSTEM (REDESIGNE 0 0 0
Dwr Cymru Welsh Water River Cynon TOWN HALL 0 0 99.9

Data Sources & Accuracy

EDM (Event Duration Monitoring) data and Consented Discharges to Controlled Waters with Conditions from Environment Agency & Data Map Wales

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.