Polluted by sewage 10,110 hours in 2025 - That's 1.17 years
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We get information about overflowing CSOs since January 2025. Here is a chart of the last three months of data for Blaenau Gwent and Rhymney, here you can see overflows in red, the darker the red, the more the CSO overflowed that day.
Each CSO has a row, the most recent data is on the right hand side.
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Donate Now| Company | Site Name | Receiving Waterway | Overflow Days | Total Duration (hours) | Total Duration (days) |
|---|---|---|---|---|---|
| Dwr Cymru Welsh Water | Brynmawr Blackrock WwTW Storm Overflow | River Clydach | 104 | 1,366 h 30m | 56.92 |
| Dwr Cymru Welsh Water | Abertysswg Troedrhiwfuwch Storm Overflow | River Rhymni | 72 | 721 h 42m | 30.04 |
| Dwr Cymru Welsh Water | Park Place Storm Overflow | River Sirhowy | 123 | 659 h 21m | 27.46 |
| Dwr Cymru Welsh Water | Beaufort Allotment Road Bridge Storm Overflow | River Ebbw | 84 | 644 h 57m | 26.83 |
| Dwr Cymru Welsh Water | Deri Riverside Walk Bargoed Storm Overflow | Nant Bargod Rhymni | 57 | 594 h 15m | 24.75 |
| Dwr Cymru Welsh Water | Bedwellty Road Bridge Storm Overflow | River Taff Bargoed | 127 | 511 h 30m | 21.29 |
| Dwr Cymru Welsh Water | New Tredegar Business Park West Storm Overflow | River Rhymni | 30 | 329 h 40m | 13.71 |
| Dwr Cymru Welsh Water | Pontlottyn Old Gasworks Storm Overflow | River Rhymni | 52 | 250 h 39m | 10.42 |
| Dwr Cymru Welsh Water | Garibaldi Bridge Storm Overflow | River Sirhowy | 59 | 238 h 15m | 9.92 |
| Dwr Cymru Welsh Water | The Square Street Abertillery Storm Overflow | River Ebbw | 34 | 238 h 5m | 9.92 |
| Dwr Cymru Welsh Water | Marine Street Industrial Estate Storm Overflow | River Ebbw | 38 | 228 h 40m | 9.5 |
| Dwr Cymru Welsh Water | Victoria Business Park Storm Overflow | River Ebbw | 19 | 199 h 20m | 8.29 |
| Dwr Cymru Welsh Water | Commercial street near Sirhowy river Storm Overflow | Sirhowy River | 58 | 189 h 45m | 7.88 |
| Dwr Cymru Welsh Water | Tredegar Greenfield Ter Storm Overflow | Sirhowy River | 53 | 183 h 26m | 7.62 |
| Dwr Cymru Welsh Water | Dukestown road Tredegar Storm Overflow | Sirhowy River | 44 | 173 h 16m | 7.21 |
| Dwr Cymru Welsh Water | Bargoed Viaduct Storm Overflow | River Rhymni | 31 | 171 h 46m | 7.12 |
| Dwr Cymru Welsh Water | South of Pochin Crescent Storm Overflow | Sirhowy River | 28 | 171 h 38m | 7.12 |
| Dwr Cymru Welsh Water | Abertillery Six Bells Colliery No. 2 Storm Overflow | Ebbw Fach River | 20 | 170 h 7m | 7.08 |
| Dwr Cymru Welsh Water | Rhymney Walk Storm Overflow | The River Rhymney | 46 | 163 h 58m | 6.79 |
| Dwr Cymru Welsh Water | The Terrace Rhymney Storm Overflow | River Rhymni | 43 | 160 h 31m | 6.67 |
| Dwr Cymru Welsh Water | Vale Terrace 1 Storm Overflow | Sirhowy River | 18 | 148 h 13m | 6.17 |
| Dwr Cymru Welsh Water | High Street Blaina Storm Overflow | Nant Yr Ystruth | 43 | 147 h 45m | 6.12 |
| Dwr Cymru Welsh Water | Steelworks Road and Clos Pen Y Cae Storm Overflow | River Ebbw | 47 | 146 h 30m | 6.08 |
| Dwr Cymru Welsh Water | Merthyr Road A4048 Roundabout Storm Overflow | Sirhowy River | 33 | 126 h 39m | 5.25 |
| Dwr Cymru Welsh Water | Heol Y Waun Storm Overflow | River Rhymney | 31 | 125 h 36m | 5.21 |
| Dwr Cymru Welsh Water | Berea Close Storm Overflow | Ebbw Fach River | 30 | 123 h 55m | 5.12 |
| Dwr Cymru Welsh Water | Vicarage Rd Rear of Hill Rest Tregerar Storm Overflow | River Sirhowy | 42 | 113 h 33m | 4.71 |
| Dwr Cymru Welsh Water | Bethania Cottages Storm Overflow | River Rhymni | 38 | 107 h 8m | 4.46 |
| Dwr Cymru Welsh Water | Factory Road Field Storm Overflow | Nant Bargoed Rhymney | 10 | 99 h 30m | 4.12 |
| Dwr Cymru Welsh Water | Carno Street Storm Overflow | River Rhymney | 34 | 94 h 25m | 3.92 |
| Dwr Cymru Welsh Water | Abertillery Six Bells Colliery No. 1 Storm Overflow | Ebbw Fach River | 10 | 81 h 42m | 3.38 |
| Dwr Cymru Welsh Water | Pont-Y-Gof Storm No.2 Overflow | River Ebbw | 7 | 77 h 34m | 3.21 |
| Dwr Cymru Welsh Water | Bargoed Old Colliery Washery Storm Overflow | River Rhymney | 35 | 75 h | 3.12 |
| Dwr Cymru Welsh Water | Pontlottyn Recreation Ground Storm Overflow | River Rhymni | 29 | 74 h 38m | 3.08 |
| Dwr Cymru Welsh Water | Beaufort Road Storm Overflow | Ebbw Fach River | 33 | 71 h 45m | 2.96 |
| Dwr Cymru Welsh Water | Junction of Scwrfa Road and Mechanic Square Storm Overflow | River Sirhowy | 27 | 71 h 7m | 2.96 |
| Dwr Cymru Welsh Water | Aubrey Terrace Overflow | Ebbw River | 24 | 66 h 35m | 2.75 |
| Dwr Cymru Welsh Water | Allotment Road Storm Overflow | River Ebbw | 12 | 62 h 41m | 2.58 |
| Dwr Cymru Welsh Water | Rassau Road Flyover Storm Overflow | Rasa Brook | 29 | 62 h 39m | 2.58 |
| Dwr Cymru Welsh Water | Steelworks Road Ebbw Vale Storm Overflow | Ebbw Fawr | 16 | 60 h 45m | 2.5 |
| Dwr Cymru Welsh Water | Glan Ebbw Terrace Storm Overflow | River Tillery | 17 | 56 h 52m | 2.33 |
| Dwr Cymru Welsh Water | Ebbw Vale Beaufort Rd Storm Overflow | River Ebbw | 41 | 56 h 24m | 2.33 |
| Dwr Cymru Welsh Water | Pont-Y-Gof Storm Overflow | Ebbw River | 28 | 55 h 40m | 2.29 |
| Dwr Cymru Welsh Water | Abertillery Tillery Street Storm Overflow | River Tillery | 22 | 52 h 21m | 2.17 |
| Dwr Cymru Welsh Water | Railway View Storm Overflow | River Sirhowy | 40 | 52 h 10m | 2.17 |
| Dwr Cymru Welsh Water | Tredegar Road Pennant Street Storm Overflow | Ebbw Fach River | 20 | 45 h 54m | 1.88 |
| Dwr Cymru Welsh Water | Pengam Road Roundabout Aberbargoed Storm Overflow | Tributary of Afon Rhymni | 22 | 45 h 21m | 1.88 |
| Dwr Cymru Welsh Water | King Street Brynmawr Storm Overflow | Ebbw Fach River | 26 | 39 h 13m | 1.62 |
| Dwr Cymru Welsh Water | South Griffin Colliery Storm Overflow | Ebbw Fach River | 11 | 38 h 14m | 1.58 |
| Dwr Cymru Welsh Water | Morgan Street Tredegar Storm Overflow | Sirhowy River | 27 | 35 h 29m | 1.46 |
| Dwr Cymru Welsh Water | Basin Football Field Storm Overflow | River Rhymni | 16 | 33 h 43m | 1.38 |
| Dwr Cymru Welsh Water | Coedcae Rassau Storm Overflow | Nant Melyn | 13 | 29 h 32m | 1.21 |
| Dwr Cymru Welsh Water | Abertillery Glandwr Street Storm Overflow | River Ebbw | 12 | 29 h 20m | 1.21 |
| Dwr Cymru Welsh Water | Market Road Nantyglo Storm Overflow | River Ebbw Fach | 6 | 29 h | 1.21 |
| Dwr Cymru Welsh Water | Vale Terrace 2 Storm Overflow | Sirhowy River | 20 | 26 h 11m | 1.08 |
| Dwr Cymru Welsh Water | Castle Street Abertillery Overflow | River Ebdw Fach | 20 | 20 h 35m | 0.83 |
| Dwr Cymru Welsh Water | Fitzroy Avenue Roundabout Ebbw Vale Overflow | River Ebbw | 9 | 20 h 17m | 0.83 |
| Dwr Cymru Welsh Water | Bryn Villas Storm Overflow | River Ebbw Fach | 8 | 19 h 39m | 0.79 |
| Dwr Cymru Welsh Water | River Road Cwm Storm Overflow | Ebbw Fach River | 9 | 18 h 30m | 0.75 |
| Dwr Cymru Welsh Water | Tredegar East of Pochin Crescent and A4048 Roundabout Storm Overflow | River Sirhowy | 5 | 18 h 27m | 0.75 |
| Dwr Cymru Welsh Water | Holland Street Ebbw Vale Overflow | River Ebbw | 16 | 12 h 12m | 0.5 |
| Dwr Cymru Welsh Water | Old School Site Nantyglo Storm Overflow | Ebbw Fach River | 6 | 8 h 58m | 0.33 |
| Dwr Cymru Welsh Water | Augusta Park Ebbw Vale Storm Overflow | Ebbw Fach River | 9 | 7 h 45m | 0.29 |
| Dwr Cymru Welsh Water | Chapel Road Six Bells Storm Overflow | River Ebbw Fach | 8 | 6 h 41m | 0.25 |
| Dwr Cymru Welsh Water | Unknown | Unknown | 21 | 6 h | 0.25 |
| Dwr Cymru Welsh Water | Unknown | Unknown | 6 | 5 h 57m | 0.21 |
| Dwr Cymru Welsh Water | Marine Street and Dyffryn Place Junction Cwm Storm Overflow | River Ebbw | 4 | 5 h 43m | 0.21 |
| Dwr Cymru Welsh Water | Ladies Row Storm Overflow | Sirhowy River | 6 | 4 h 38m | 0.17 |
| Dwr Cymru Welsh Water | Limestone Road Storm Overflow | Ebbw Fach River | 4 | 3 h 32m | 0.12 |
| Dwr Cymru Welsh Water | Brithdir Station Storm Overflow | River Rhymni | 2 | 3 h 15m | 0.12 |
| Dwr Cymru Welsh Water | Brooklyn Terrace Storm Overflow | River Ebbw | 5 | 2 h 43m | 0.08 |
| Dwr Cymru Welsh Water | Bargoed Station Road Storm Overflow | River Rhymni | 4 | 2 h 41m | 0.08 |
| Dwr Cymru Welsh Water | Commercial Road Abertillery Storm Overflow | River Ebbw | 4 | 2 h 14m | 0.08 |
| Dwr Cymru Welsh Water | Excelsior Street Storm Overflow | River Ebbw | 3 | 1 h 59m | 0.04 |
| Dwr Cymru Welsh Water | Beaufort Terrace Storm Overflow | River Ebbw | 2 | 1 h 44m | 0.04 |
| Dwr Cymru Welsh Water | Pant Street Storm Overflow | River Rhymni | 4 | 1 h | 0.04 |
| Dwr Cymru Welsh Water | Victoria Road Six Bells Storm Overflow | Ebbw Fach River | 1 | 0 h 45m | 0 |
| Dwr Cymru Welsh Water | Tredegar Road Rees Street Storm Overflow | Ebbw Fach River | 2 | 0 h 43m | 0 |
| Dwr Cymru Welsh Water | Alexandra Place Tredegar Storm Overflow | The Sirhowy River | 3 | 0 h 43m | 0 |
| Dwr Cymru Welsh Water | Lillian Grove Rear Storm Overflow | Ebbw Fach River | 2 | 0 h 38m | 0 |
| Dwr Cymru Welsh Water | High Street West Abertillery Overflow | River Tillery | 2 | 0 h 29m | 0 |
| Dwr Cymru Welsh Water | Badminton Grove Beaufort Road Storm Overflow | Ebbw Fawr | 1 | 0 h 15m | 0 |
| Dwr Cymru Welsh Water | Station Hill Abertillery Storm Overflow | River Tillery | 1 | 0 h 15m | 0 |
| Dwr Cymru Welsh Water | Crumlin Road Llanhilleth Storm Overflow | River Ebbw | 1 | 0 h 15m | 0 |
| Dwr Cymru Welsh Water | Vale Terrace 3 Storm Overflow | River Sirhowy | 1 | 0 h 15m | 0 |
| Dwr Cymru Welsh Water | Queens Square Ebbw Vale Storm Overflow | Ebbw Fach River | 1 | 0 h 15m | 0 |
| Dwr Cymru Welsh Water | School Street New Tredegar Overflow | River Rhymni | 1 | 0 h 14m | 0 |
| Dwr Cymru Welsh Water | Six Bells Road Storm Overflow | Ebbw Fach River | 1 | 0 h 14m | 0 |
| Dwr Cymru Welsh Water | Canning Street Storm Overflow | River Ebbw | 1 | 0 h 6m | 0 |
| Dwr Cymru Welsh Water | Harcourt Street Rear Storm Overflow | River Ebbw | 0 | 0 h | 0 |
| Dwr Cymru Welsh Water | High Street Abertillery Storm Overflow | River Tillery | 0 | 0 h | 0 |
| Dwr Cymru Welsh Water | Nantyglo Farm Road Junction of Market Road Storm Overflow | Ebbw Fach River | 0 | 0 h | 0 |
| Dwr Cymru Welsh Water | Sannan Street Storm Overflow | River Rhymni | 0 | 0 h | 0 |
| Dwr Cymru Welsh Water | Tillery Street Storm Overflow | River Tyleri | 0 | 0 h | 0 |
| Dwr Cymru Welsh Water | Rose Hayworth Road Storm Overflow | River Ebbw Fach | 0 | 0 h | 0 |
| Dwr Cymru Welsh Water | Lamb's Square Lower Square Storm Overflow | River Ebbw | 0 | 0 h | 0 |
| Dwr Cymru Welsh Water | Westville Rhymney Overflow | River Rhymni | 0 | 0 h | 0 |
| Dwr Cymru Welsh Water | Llwyn Helyg Storm Overflow | Sirhowy River | 0 | 0 h | 0 |
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.