Merthyr Tydfil and Aberdare - Live Sewage

Polluted by sewage 13,928 hours in 2026 - That's 1.61 years so far..

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Contains OS Data © Crown copyright & database right 2021-2024
© Top of the Poops 2021-2024

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View Annual Sewage Data

You're looking at the totals that we have calculated for sewage in Merthyr Tydfil and Aberdare so far for 2026. It is an estimate, based on very poor quality live data from the Water Companies. The water companies report their sewage to the Environment Agency every year in April. You can see the last reported year in the other page

What's a potential overflow? If the CSO goes 'Offline' while its Overflowing, we don't know if it stopped overflowing until we get a 'Stop' event.

Totals for Merthyr Tydfil and Aberdare in 2026

Sewage13,928 hours
Monitoring offline0 hours
Potential pollution0 hours
Storm overflows80

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Daily Data

Jan - 3,160 hours
Feb - 3,411 hours
Mar - 1,381 hours
Apr - 538 hours
May - 1,730 hours
Jun - 1,744 hours
Jul - 0 hours
Aug - 118 hours
Sept - 285 hours
Oct - 1,294 hours
Nov - 262 hours
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Totals so far

Company Site Name Receiving Waterway Overflow Days Total Duration (hours) Offline/Potential Pollution
Dwr Cymru Welsh Water Hirwaun Industrial Estate WwTW Storm Overflow Afon Camnant 187 3,764h 5m -
Dwr Cymru Welsh Water Pontsticill WwTW Storm Overflow River Taff 58 1,077h 15m -
Dwr Cymru Welsh Water Rocky Road 1 Storm Overflow Nant Morlais 68 1,006h 40m -
Dwr Cymru Welsh Water Mikes Field Storm Overflow River Cynon 77 871h 39m -
Dwr Cymru Welsh Water Cilmery WwTW Storm Overflow Afon Chwefri 74 827h 5m -
Dwr Cymru Welsh Water Bethesda Street Merthyr Tydfil Storm Overflow River Taff 80 825h 57m -
Dwr Cymru Welsh Water Aberaman Park West Storm Overflow River Cynon 74 754h 7m -
Dwr Cymru Welsh Water Trelewis Glynbargoed Road Storm Overflow Pandy Brook 65 679h 4m -
Dwr Cymru Welsh Water Merthyr Road Bridge Storm Overflow River Cynon 64 676h -
Dwr Cymru Welsh Water Pontbren Storm Overflow River Cynon 44 409h 27m -
Dwr Cymru Welsh Water Pontrhun Bridge Storm Overflow River Taff 62 326h 6m -
Dwr Cymru Welsh Water East of Rounabout A4102 jct with High Street Storm Overflow Morlais Brook 52 300h 49m -
Dwr Cymru Welsh Water Monk Street No1 Storm Overflow River Cynon 59 288h 55m -
Dwr Cymru Welsh Water Meirion Street Roundabout Trecynon Storm Overflow River Cynon 53 246h 14m -
Dwr Cymru Welsh Water Dare Road Storm Overflow River Dare 37 224h 20m -
Dwr Cymru Welsh Water Cyfarthfa Road Storm Overflow River Taff 46 208h 13m -
Dwr Cymru Welsh Water Llwydcoed Road New Scales Houses Storm Overflow Unnamed Tribuatary of Afon Cynon 16 199h 36m -
Dwr Cymru Welsh Water Gellifaelog Old Road Storm Overflow Morlais Brook 27 181h 14m -
Dwr Cymru Welsh Water Oakland Street Bedlinog Storm Overflow River Taff 27 176h 54m -
Dwr Cymru Welsh Water Pant-Y-Cerdin Storm Overflow Aberdare Canal 30 125h 16m -
Dwr Cymru Welsh Water Station Street Aberdare Storm Overflow River Cynon 37 111h 49m -
Dwr Cymru Welsh Water Maes Y Ffion Storm Overflow Nant-Y-Derlwyn 35 95h 27m -
Dwr Cymru Welsh Water Bro Deg 2 Storm Overflow River Cynon 31 93h 22m -
Dwr Cymru Welsh Water Merthyr Tydfil College Car Park Storm Overflow River Taff 26 61h 44m -
Dwr Cymru Welsh Water Pen-Y-Darren Rd jct with Gwalia Place Storm Overflow Morlais Brook 19 47h 25m -
Dwr Cymru Welsh Water Tai Mawr Way Storm Overflow River Taff 19 47h 1m -
Dwr Cymru Welsh Water Merthyr Tydfil Industrial Park Storm Overflow Pentrebach Brook 24 39h 59m -
Dwr Cymru Welsh Water Gladstone Street Storm Overflow Tributary of Afon Aman 19 38h 19m -
Dwr Cymru Welsh Water Trenant 1 Storm Overflow River Cynon 23 36h 55m -
Dwr Cymru Welsh Water Bro Deg 1 Storm Overflow River Cynon 15 33h 6m -
Dwr Cymru Welsh Water Tan Y Bryn Gardens Llwydcoed Overflow River Cynon 13 23h 24m -
Dwr Cymru Welsh Water Dean Street Aberdare Storm Overflow River Cynon 21 21h 58m -
Dwr Cymru Welsh Water Heol Pendarren Storm Overflow Ditch to Nant Gwrangon 5 12h 22m -
Dwr Cymru Welsh Water Sion Terrace Storm Overflow River Cynon 6 12h 8m -
Dwr Cymru Welsh Water Wind Street Storm Overflow River Amman 8 10h 40m -
Dwr Cymru Welsh Water Bute Place Hirwaun Storm Overflow River Cynon 13 7h 36m -
Dwr Cymru Welsh Water Canal Road Cwmbach Storm Overflow River Cynon 3 5h 43m -
Dwr Cymru Welsh Water Swan Street Merthyr Tydfil Storm Overflow River Taff 7 5h 27m -
Dwr Cymru Welsh Water Nr Aberaman Park Ind. Est. Storm Overflow RiverAman 4 5h 19m -
Dwr Cymru Welsh Water Cwmbach Storm Overflow River Cynon 1 5h -
Dwr Cymru Welsh Water Glan Road Storm Overflow River Dare 6 4h 23m -
Dwr Cymru Welsh Water Fiddlers Elbow Quakers Yard Storm Overflow River Taff 5 4h 12m -
Dwr Cymru Welsh Water Tram Road Side Storm Overflow River Taff 9 4h 11m -
Dwr Cymru Welsh Water Erw Las Rear Footpath Storm Overflow River Cynon 5 4h 8m -
Dwr Cymru Welsh Water Cwmbach Maeshyfryd Stoem Overflow River Cynon 2 3h 59m -
Dwr Cymru Welsh Water Commercial Street Aberdare Overflow River Cynon 3 3h 30m -
Dwr Cymru Welsh Water Pit Place Cwmbach Overflow River Cynon 3 3h 27m -
Dwr Cymru Welsh Water Glancynon Terrace Storm Overflow Nant Gwawr 5 2h 27m -
Dwr Cymru Welsh Water Aberaman Curre Street Storm Overflow Unnamed Stream 5 2h 16m -
Dwr Cymru Welsh Water Cardiff Road Aberaman Storm Overflow River Cynon 6 2h 15m -
Dwr Cymru Welsh Water Abernant Road Aberdare Storm Overflow Nant Wenallt 1 1h 27m -
Dwr Cymru Welsh Water Pont-y-Cefn Storm Overflow Taf Fechan 1 1h 14m -
Dwr Cymru Welsh Water Bron Haul Storm Overflow River Cynon 1 0h 59m -
Dwr Cymru Welsh Water Wellington St No1 Storm overflow River Cynon 2 0h 59m -
Dwr Cymru Welsh Water Goitre Lane Storm Overflow Goitre Brook 2 0h 58m -
Dwr Cymru Welsh Water Elizabeth Street Storm Overflow Tributary of River Cynon 3 0h 56m -
Dwr Cymru Welsh Water Bro Deg Canal Road Junction Storm Overflow River Cynon 2 0h 56m -
Dwr Cymru Welsh Water Well Place Storm Overflow River Cynon 1 0h 44m -
Dwr Cymru Welsh Water Aberfan Trunk Sewer Storm Overflow River Taff 1 0h 20m -
Dwr Cymru Welsh Water Market Street Dowlais Storm Overflow Unnamed Tributary Leading to Nant Morlais 1 0h 17m -
Dwr Cymru Welsh Water Park View Terrace Storm Overflow River Cynon 1 0h 15m -
Dwr Cymru Welsh Water Bryngolwg Storm Overflow River Cynon 1 0h 15m -
Dwr Cymru Welsh Water Cynon Street Storm Overflow Unnamed Tributary to Afon Amman 0 0h -
Dwr Cymru Welsh Water Hirwaun Tramway Storm Overflow Unnamed Stream 0 0h -
Dwr Cymru Welsh Water Troedyrhiw Storm Overflow River Taff 0 0h -
Dwr Cymru Welsh Water Merthyr Vale Trunk Sewer Storm Overflow River Taff 0 0h -
Dwr Cymru Welsh Water Tudor Terrace Rear Storm Overflow Gadlys Feeder 0 0h -
Dwr Cymru Welsh Water Rocky Road 2 Storm Overflow Morlais Brook 0 0h -
Dwr Cymru Welsh Water Foundry View Aberaman No 2 Storm Overflow River Amman 0 0h -
Dwr Cymru Welsh Water Foundry View Aberaman No 1 Overflow River Amman 0 0h -
Dwr Cymru Welsh Water Muriel Terrace Merthyr Tydfil Overflow River Taff 0 0h -
Dwr Cymru Welsh Water Trecynon Harriet Street Storm Overflow Nant-Y-Derlwyn 0 0h -
Dwr Cymru Welsh Water Hirwaun Mangoed Storm Overflow River Cynon 0 0h -
Dwr Cymru Welsh Water Rodericks Terrace Storm Overflow River Taff 0 0h -
Dwr Cymru Welsh Water Fforchaman Road Cwmaman River Amman 0 0h -
Dwr Cymru Welsh Water David Street Aberaman Storm Overflow River Cynon 0 0h -
Dwr Cymru Welsh Water Balaclava Road 2 Storm Overflow Morlais Brook 0 0h -
Dwr Cymru Welsh Water Wyndham Crescent Aberaman Storm Overflow River Cynon 0 0h -
Dwr Cymru Welsh Water Phyllis Street Storm Overflow River Taff 0 0h -
Dwr Cymru Welsh Water Yew Street Storm Overflow River Taff 0 0h -

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

Annual figures up to and including 2025 come from official water company returns. The 2026 figure is our own estimate, derived continuously from the companies' live data feeds.

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.