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Polluted by sewage 6,943 hours in 2025
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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 Montgomeryshire and Glyndwr, 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 | Commins Coch Storm Overflow | River Twymyn | 102 | 2,288 h 29m | 95.33 |
| Dwr Cymru Welsh Water | Llanbrynmair Tafolwern WwTW Storm Overflow | Afon Iaen | 94 | 1,855 h 4m | 77.29 |
| Dwr Cymru Welsh Water | Machynlleth WwTW Settled Storm Overflow | Garsiwn Ffos | 52 | 400 h | 16.67 |
| Dwr Cymru Welsh Water | Machynlleth WwTW Storm Overflow | River Dyfi | 52 | 400 h | 16.67 |
| Dwr Cymru Welsh Water | Glyn Ceiriog WwTW Overflow | River Ceiriog | 56 | 264 h 9m | 11 |
| Dwr Cymru Welsh Water | Rhosllanerchrugog Pant Storm Overflow | Afon Goch | 61 | 233 h 47m | 9.71 |
| Dwr Cymru Welsh Water | Cefn Mawr WwTW Storm Overflow | River Dee | 36 | 183 h 45m | 7.62 |
| Dwr Cymru Welsh Water | Ceinws Esgairgeiliog Storm Overflow | Afon Glesrych Estuary | 16 | 167 h 45m | 6.96 |
| Dwr Cymru Welsh Water | Pontfadog WwTW Storm Overflow | River Ceiriog | 19 | 144 h 30m | 6 |
| Dwr Cymru Welsh Water | Bersham Colliery Railway Storm Overflow | Glanyrafon Brook | 25 | 140 h | 5.83 |
| Dwr Cymru Welsh Water | Cefn Storm Overflow | Tref-Y-Nant Brook | 39 | 111 h 30m | 4.62 |
| Dwr Cymru Welsh Water | Heol Y Doll Machynlleth Storm Overflow | Garsiwn ditch | 66 | 96 h 6m | 4 |
| Dwr Cymru Welsh Water | Afon Eitha Storm Overflow | Afon Goch | 43 | 79 h 45m | 3.29 |
| Dwr Cymru Welsh Water | Off Llangollen Road Cefn-mawr Storm Overflow | Tref-Y-Nant Brook | 17 | 69 h 48m | 2.88 |
| Dwr Cymru Welsh Water | Ffordd Offa Rhosllanerchrugog Storm Overflow | Unnamed Watercourse | 26 | 53 h 19m | 2.21 |
| Dwr Cymru Welsh Water | North West of Bro-Ddewi Dolywern Storm Overflow | River Ceiriog | 19 | 50 h 46m | 2.08 |
| Dwr Cymru Welsh Water | Penycae Storm Overflow | Afon Eitha | 10 | 47 h 30m | 1.96 |
| Dwr Cymru Welsh Water | Bangor Road Rhosllanerchrugog Storm Overflow | Black Brook | 22 | 42 h 30m | 1.75 |
| Dwr Cymru Welsh Water | Paddock Row Ruabon Storm Overflow No2 | Afon Eitha | 15 | 41 h 30m | 1.71 |
| Dwr Cymru Welsh Water | Chirk Canal Wood Storm Overflow | River Bradley | 13 | 39 h 45m | 1.62 |
| Dwr Cymru Welsh Water | Machynlleth Popular Terrace Storm Overflow | Unnamed Ditch | 13 | 33 h 6m | 1.38 |
| Dwr Cymru Welsh Water | Y Gamer Glyn Ceiriog Storm Overflow | River Ceiriog | 33 | 29 h 32m | 1.21 |
| Dwr Cymru Welsh Water | Bryn Glas Rhosllanerchrugog Storm Overflow | Afon Goch | 20 | 26 h 30m | 1.08 |
| Dwr Cymru Welsh Water | Trofryn Rhosllanerchrugog Overflow | River Eitha | 9 | 24 h 55m | 1 |
| Dwr Cymru Welsh Water | Offa Street Chirk Storm Overflow | Tributary of the Afon Dyfrdwy | 6 | 23 h 26m | 0.96 |
| Dwr Cymru Welsh Water | Colliery Road Rhostyllen Storm Overflow | Glanyrafon Brook | 26 | 22 h 30m | 0.92 |
| Dwr Cymru Welsh Water | Aberderfyn Road Rhosllanerchrugog Storm Overflow | Aberderfyn | 14 | 22 h 6m | 0.92 |
| Dwr Cymru Welsh Water | Park Road Rhosymedre Storm Overflow | Tributary of the River Dee | 7 | 16 h 26m | 0.67 |
| Dwr Cymru Welsh Water | Next to Bridge Newbridge Overflow | River Dee | 5 | 11 h | 0.46 |
| Dwr Cymru Welsh Water | Paddock Row Ruabon Storm Overflow | Afon Eitha | 3 | 8 h 32m | 0.33 |
| Dwr Cymru Welsh Water | Garsiwn Ditch Storm Overflow | Garsiwn Ditch | 10 | 7 h | 0.29 |
| Dwr Cymru Welsh Water | New Road Wrexham Storm Overflow | Tref-Y-Nant Brook | 9 | 6 h 30m | 0.25 |
| Dwr Cymru Welsh Water | South of Hampden Way Wrexham Storm Overflow | Tributary of the Afon Dyfrdwy | 2 | 1 h 14m | 0.04 |
| Dwr Cymru Welsh Water | Dolywern WwTW Storm Overflow | River Ceiriog | 2 | 0 h 45m | 0 |
| Dwr Cymru Welsh Water | Chirk Settled Storm Overflow | River Bradley | 0 | 0 h | 0 |
| Dwr Cymru Welsh Water | Pont-Yr-Afon Field Storm Overflow | Afon Eitha | 0 | 0 h | 0 |
| Dwr Cymru Welsh Water | Machynlleth WwTW Inlet Storm Overflow | Garsiwn Ditch | 0 | 0 h | 0 |
| Dwr Cymru Welsh Water | New Hall Road Ruabon Storm Overflow | Afon Goch | 0 | 0 h | 0 |
| Dwr Cymru Welsh Water | Unknown | Unknown | 0 | 0 h | 0 |
| Dwr Cymru Welsh Water | Llangurig Storm Overflow | River Wye | 0 | 0 h | 0 |
| Dwr Cymru Welsh Water | Bontdolgadfan Storm Overflow | River Twymyn | 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.
Get in touch if you have queries or want to discuss our data.
press [at] top-of-the-poops.org