Top of the Poops | Constituency Sewage Map - Live Data| Merthyr Tydfil and Aberdare

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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.

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Constituencies near Merthyr Tydfil and Aberdare

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	45	1,003 h	-
Dwr Cymru Welsh Water	Pontsticill WwTW Storm Overflow	River Taff	41	899 h 20m	-
Dwr Cymru Welsh Water	Cilmery WwTW Storm Overflow	Afon Chwefri	46	737 h	-
Dwr Cymru Welsh Water	Mikes Field Storm Overflow	River Cynon	37	600 h 45m	-
Dwr Cymru Welsh Water	Aberaman Park West Storm Overflow	River Cynon	35	517 h 30m	-
Dwr Cymru Welsh Water	Pontbren Storm Overflow	River Cynon	29	296 h 26m	-
Dwr Cymru Welsh Water	East of Rounabout A4102 jct with High Street Storm Overflow	Morlais Brook	31	258 h 2m	-
Dwr Cymru Welsh Water	Pontrhun Bridge Storm Overflow	River Taff	30	211 h	-
Dwr Cymru Welsh Water	Oakland Street Bedlinog Storm Overflow	River Taff	21	174 h 13m	-
Dwr Cymru Welsh Water	Monk Street No1 Storm Overflow	River Cynon	28	166 h	-
Dwr Cymru Welsh Water	Rocky Road 1 Storm Overflow	Nant Morlais	15	139 h 23m	-
Dwr Cymru Welsh Water	Meirion Street Roundabout Trecynon Storm Overflow	River Cynon	26	130 h 15m	-
Dwr Cymru Welsh Water	Gellifaelog Old Road Storm Overflow	Morlais Brook	20	120 h 50m	-
Dwr Cymru Welsh Water	Trelewis Glynbargoed Road Storm Overflow	Pandy Brook	27	117 h 32m	-
Dwr Cymru Welsh Water	Dare Road Storm Overflow	River Dare	14	99 h 51m	-
Dwr Cymru Welsh Water	Pant-Y-Cerdin Storm Overflow	Aberdare Canal	20	91 h 57m	-
Dwr Cymru Welsh Water	Llwydcoed Road New Scales Houses Storm Overflow	Unnamed Tribuatary of Afon Cynon	7	81 h 28m	-
Dwr Cymru Welsh Water	Merthyr Road Bridge Storm Overflow	River Cynon	18	72 h 45m	-
Dwr Cymru Welsh Water	Station Street Aberdare Storm Overflow	River Cynon	18	72 h	-
Dwr Cymru Welsh Water	Maes Y Ffion Storm Overflow	Nant-Y-Derlwyn	16	52 h 22m	-
Dwr Cymru Welsh Water	Bethesda Street Merthyr Tydfil Storm Overflow	River Taff	20	51 h 45m	-
Dwr Cymru Welsh Water	Bro Deg 2 Storm Overflow	River Cynon	14	38 h 22m	-
Dwr Cymru Welsh Water	Merthyr Tydfil Industrial Park Storm Overflow	Pentrebach Brook	12	26 h 33m	-
Dwr Cymru Welsh Water	Merthyr Tydfil College Car Park Storm Overflow	River Taff	10	23 h 30m	-
Dwr Cymru Welsh Water	Gladstone Street Storm Overflow	Tributary of Afon Aman	9	18 h 55m	-
Dwr Cymru Welsh Water	Cyfarthfa Road Storm Overflow	River Taff	13	15 h 11m	-
Dwr Cymru Welsh Water	Pen-Y-Darren Rd jct with Gwalia Place Storm Overflow	Morlais Brook	7	12 h 59m	-
Dwr Cymru Welsh Water	Trenant 1 Storm Overflow	River Cynon	7	10 h 38m	-
Dwr Cymru Welsh Water	Tai Mawr Way Storm Overflow	River Taff	6	9 h 41m	-
Dwr Cymru Welsh Water	Dean Street Aberdare Storm Overflow	River Cynon	9	8 h 30m	-
Dwr Cymru Welsh Water	Tan Y Bryn Gardens Llwydcoed Overflow	River Cynon	6	7 h 10m	-
Dwr Cymru Welsh Water	Bro Deg 1 Storm Overflow	River Cynon	8	6 h 57m	-
Dwr Cymru Welsh Water	Sion Terrace Storm Overflow	River Cynon	3	5 h 43m	-
Dwr Cymru Welsh Water	Nr Aberaman Park Ind. Est. Storm Overflow	RiverAman	4	5 h 19m	-
Dwr Cymru Welsh Water	Bute Place Hirwaun Storm Overflow	River Cynon	5	3 h 42m	-
Dwr Cymru Welsh Water	Wind Street Storm Overflow	River Amman	5	3 h 13m	-
Dwr Cymru Welsh Water	Tram Road Side Storm Overflow	River Taff	5	2 h 43m	-
Dwr Cymru Welsh Water	Heol Pendarren Storm Overflow	Ditch to Nant Gwrangon	3	2 h 39m	-
Dwr Cymru Welsh Water	Pit Place Cwmbach Overflow	River Cynon	2	2 h 13m	-
Dwr Cymru Welsh Water	Fiddlers Elbow Quakers Yard Storm Overflow	River Taff	2	1 h 58m	-
Dwr Cymru Welsh Water	Swan Street Merthyr Tydfil Storm Overflow	River Taff	2	1 h 45m	-
Dwr Cymru Welsh Water	Abernant Road Aberdare Storm Overflow	Nant Wenallt	1	1 h 27m	-
Dwr Cymru Welsh Water	Aberaman Curre Street Storm Overflow	Unnamed Stream	3	1 h 18m	-
Dwr Cymru Welsh Water	Glancynon Terrace Storm Overflow	Nant Gwawr	2	1 h 14m	-
Dwr Cymru Welsh Water	Pont-y-Cefn Storm Overflow	Taf Fechan	1	1 h 14m	-
Dwr Cymru Welsh Water	Glan Road Storm Overflow	River Dare	3	1 h 9m	-
Dwr Cymru Welsh Water	Bron Haul Storm Overflow	River Cynon	1	0 h 59m	-
Dwr Cymru Welsh Water	Cardiff Road Aberaman Storm Overflow	River Cynon	2	0 h 43m	-
Dwr Cymru Welsh Water	Elizabeth Street Storm Overflow	Tributary of River Cynon	2	0 h 41m	-
Dwr Cymru Welsh Water	Wellington St No1 Storm overflow	River Cynon	1	0 h 29m	-
Dwr Cymru Welsh Water	Canal Road Cwmbach Storm Overflow	River Cynon	1	0 h 29m	-
Dwr Cymru Welsh Water	Goitre Lane Storm Overflow	Goitre Brook	1	0 h 29m	-
Dwr Cymru Welsh Water	Bro Deg Canal Road Junction Storm Overflow	River Cynon	1	0 h 27m	-
Dwr Cymru Welsh Water	Market Street Dowlais Storm Overflow	Unnamed Tributary Leading to Nant Morlais	1	0 h 17m	-
Dwr Cymru Welsh Water	Park View Terrace Storm Overflow	River Cynon	1	0 h 15m	-
Dwr Cymru Welsh Water	Bryngolwg Storm Overflow	River Cynon	1	0 h 15m	-
Dwr Cymru Welsh Water	Aberfan Trunk Sewer Storm Overflow	River Taff	0	0 h	-
Dwr Cymru Welsh Water	Muriel Terrace Merthyr Tydfil Overflow	River Taff	0	0 h	-
Dwr Cymru Welsh Water	Cynon Street Storm Overflow	Unnamed Tributary to Afon Amman	0	0 h	-
Dwr Cymru Welsh Water	Erw Las Rear Footpath Storm Overflow	River Cynon	0	0 h	-
Dwr Cymru Welsh Water	Hirwaun Mangoed Storm Overflow	River Cynon	0	0 h	-
Dwr Cymru Welsh Water	Wyndham Crescent Aberaman Storm Overflow	River Cynon	0	0 h	-
Dwr Cymru Welsh Water	Troedyrhiw Storm Overflow	River Taff	0	0 h	-
Dwr Cymru Welsh Water	Fforchaman Road Cwmaman	River Amman	0	0 h	-
Dwr Cymru Welsh Water	Merthyr Vale Trunk Sewer Storm Overflow	River Taff	0	0 h	-
Dwr Cymru Welsh Water	Trecynon Harriet Street Storm Overflow	Nant-Y-Derlwyn	0	0 h	-
Dwr Cymru Welsh Water	Cwmbach Maeshyfryd Stoem Overflow	River Cynon	0	0 h	-
Dwr Cymru Welsh Water	Phyllis Street Storm Overflow	River Taff	0	0 h	-
Dwr Cymru Welsh Water	Cwmbach Storm Overflow	River Cynon	0	0 h	-
Dwr Cymru Welsh Water	David Street Aberaman Storm Overflow	River Cynon	0	0 h	-
Dwr Cymru Welsh Water	Tudor Terrace Rear Storm Overflow	Gadlys Feeder	0	0 h	-
Dwr Cymru Welsh Water	Hirwaun Tramway Storm Overflow	Unnamed Stream	0	0 h	-
Dwr Cymru Welsh Water	Balaclava Road 2 Storm Overflow	Morlais Brook	0	0 h	-
Dwr Cymru Welsh Water	Yew Street Storm Overflow	River Taff	0	0 h	-
Dwr Cymru Welsh Water	Foundry View Aberaman No 2 Storm Overflow	River Amman	0	0 h	-
Dwr Cymru Welsh Water	Rocky Road 2 Storm Overflow	Morlais Brook	0	0 h	-
Dwr Cymru Welsh Water	Foundry View Aberaman No 1 Overflow	River Amman	0	0 h	-
Dwr Cymru Welsh Water	Commercial Street Aberdare Overflow	River Cynon	0	0 h	-
Dwr Cymru Welsh Water	Rodericks Terrace Storm Overflow	River Taff	0	0 h	-

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

1,003 h

Dwr Cymru Welsh Water

Pontsticill WwTW Storm Overflow