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Casnewydd Islwyn

Polluted by sewage 2,641 times in 2025 lasting 20,138 hours - That's 2.33 years!

Monitoring was disabled in some locations, so could be more

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Totals for Casnewydd Islwyn in 2025

65 Sites polluted by Dwr Cymru Welsh Water

2,641 sewage dumps

20,138 hours duration

That's 2.33 years. On average 7.2 times a day

Change Over Time

Senedd Constituencies near Casnewydd Islwyn

Westminster Constituencies within Casnewydd Islwyn

To see live data by overflow, go to the Westminster Constituency, then 'live data'

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Pollution Summary 2025

Here are all the reported sewage overflow totals for Casnewydd Islwyn in 2025. 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 71 CSO Combined Sewage Overflow - a device that, when operating, pours combined rainwater & sewage into a waterway locations had reporting enabled for less than half the year. Of these 2 had zero reporting.

Company	Waterway	Site	Sewage Dumps	Duration (Hours)	Reporting %
Dwr Cymru Welsh Water	River Ebbw	Tanybryn Risca CSO, Pontymister	196	3,474	98.9
Dwr Cymru Welsh Water	Ebbw River	CSO 36 CWMCARN HIGH SCHOOL CHAPEL F	133	2,358	99.9
Dwr Cymru Welsh Water	Severn Estuary	RHYMNEY VALLEY TRUNK SEWER CSO	140	2,262	99.9
Dwr Cymru Welsh Water	River Rhymney	A CSO 700M SE OF PLAS MACHEN COTAGE	102	1,509	85.7
Dwr Cymru Welsh Water	Severn Estuary	WESTERN VALLEY TRUNK SEWER CSO	59	1,319	99.8
Dwr Cymru Welsh Water	Malpas Brook	Malpas Road CSO	136	1,199	99.9
Dwr Cymru Welsh Water	Julians Pill	NASH STW WEST NASH ROAD NEWPORT	64	740	99.9
Dwr Cymru Welsh Water	Monks Ditch	Underwood PS Underwood Newport	72	735	99.9
Dwr Cymru Welsh Water	Ebbw Estuary	Maesglas SPS	63	715	96.8
Dwr Cymru Welsh Water	Ebbw River	Car Park of Old Globe CSO, St John Crescent	85	691	94.2
Dwr Cymru Welsh Water	Ebbw Fawr	Tredegar Park Golf Club CSO	94	592	99.1
Dwr Cymru Welsh Water	Ebbw River	CSO 47 ALCAN WORKS ROGERSTONE	46	437	98
Dwr Cymru Welsh Water	Rhynys Brook	4 Tredegar Terrace CSO	35	375	99.8
Dwr Cymru Welsh Water	River Ebbw	CSO 33 REAR BRYNGWYN ROAD/HIGH ST	51	272	99.9
Dwr Cymru Welsh Water	River Ebbw	Crosskeys Waunfawr Park CSO	26	227	97.6
Dwr Cymru Welsh Water	Malpas Brook	Westfield Way/Huxley Green CSO	62	227	99.9
Dwr Cymru Welsh Water	Usk Estuary	Pill South B Pumping Station	66	226	99.9
Dwr Cymru Welsh Water	River Usk	CSO at Christchurch WWTW	75	214	93.8
Dwr Cymru Welsh Water	Pillmawr Creek, River Usk	Rowan Way SPS	37	210	99.9
Dwr Cymru Welsh Water	Sirhowy River	Blackwood Cwmgelli CSO	66	205	99.4
Dwr Cymru Welsh Water	Nant Carn Brook	Pontywaun CSO, Newport	53	194	98.4
Dwr Cymru Welsh Water	River Usk Estuary	Pill North PS North Octopus Rdbt	69	164	99.9
Dwr Cymru Welsh Water	River Usk	St Cadocs Hospital CSO	51	150	99.6
Dwr Cymru Welsh Water	River Ebbw	MALVERN TERRACE CSO	21	148	99.7
Dwr Cymru Welsh Water	Pillmawr Creek	R/O 228 Pilton Vale CSO, Newport	24	147	99.6
Dwr Cymru Welsh Water	Ebbw Fawr	CRUMLIN SWFFRYD CSO CAERPHILLY	82	141	99.3
Dwr Cymru Welsh Water	River Usk Estuary	SPS At Corporation Road Liswerry	76	129	99.8
Dwr Cymru Welsh Water	Sirhowy River	Blackwood Oakdale Rhiw Hill CSO	41	105	89.2
Dwr Cymru Welsh Water	River Sirhowy	CSO 42 92 Tredegar St Cross Keys	12	83	99.9
Dwr Cymru Welsh Water	Sirhowy River	CSO CWM ROAD ARGOED CAERPHILLY	23	71	99.7
Dwr Cymru Welsh Water	Malpas Brook	Bettws Lane SPS Newport	13	67	100
Dwr Cymru Welsh Water	River Sirhowy	CSO 16 Woodfield Row Blackwood	25	63	99.9
Dwr Cymru Welsh Water	Pillmawr Creek	Woodlands (Horrocks Close) SPS	19	58	99.9
Dwr Cymru Welsh Water	River Sirhowy	Blackwood 100 Steps CSO	37	57	97.6
Dwr Cymru Welsh Water	River Usk Estuary	CSO ADJ SHAFTESBURY PS NEWPORT	8	52	99.9
Dwr Cymru Welsh Water	River Ebbw	S/O 108 Commercial St, Risca CSO	36	50	99.7
Dwr Cymru Welsh Water	Ebbw River	15 Tregwilym Close CSO	35	47	99.4
Dwr Cymru Welsh Water	Ebbw Fawr	Rhiwderin No 6258 in Field CSO	23	40	99.7
Dwr Cymru Welsh Water	Lliswerry Pill Reen	Hartridge Farm SPS	9	37	99.9
Dwr Cymru Welsh Water	River Usk	A Combined Sewer Overflow St Julian	31	34	99.9
Dwr Cymru Welsh Water	Liswerry Pill Reen	SOMERTON ROAD BALMORAL ROAD CSO NEW	36	33	99.9
Dwr Cymru Welsh Water	Rhynys Brook	Rifleman St CSO, Risca	28	30	98.8
Dwr Cymru Welsh Water	Pillmawr Creek	27 Wavell Drive CSO	16	27	88
Dwr Cymru Welsh Water	River Ebbw	WVTS-North Celynen Colliery CSO	4	26	99.1
Dwr Cymru Welsh Water	River Ebbw	CSO 52 TT Electronics Tregwilym Ind	3	21	99.9
Dwr Cymru Welsh Water	Monks Ditch	Maple Close CSO, Underwood	11	19	100
Dwr Cymru Welsh Water	Liswerry Pill Reen	CSO at Newport Chepstow Road Near No589	14	17	100
Dwr Cymru Welsh Water	River Ebbw	Forge Lane near Vicarage CSO, Bassaleg	25	14	86.8
Dwr Cymru Welsh Water	Pillmawr Reen	CSO AT NEWPORT PILLMAWR RD RELIEF SEW	20	13	100
Dwr Cymru Welsh Water	Ebbw Fawr	Thornhill Gardens CSO, Rogerstone	19	12	99.7
Dwr Cymru Welsh Water	Liswerry Pill	Chepstsow Road CSO	16	12	99.9
Dwr Cymru Welsh Water	Pillmawr Creek	11 Robertson Way CSO, Newport	10	11	100
Dwr Cymru Welsh Water	Nant Gwyddon Via Surface Water Sewer And A Culvert	High Street CSO, Abercarn	33	11	99.8
Dwr Cymru Welsh Water	Sirhowy River	Markham Colliery Gun Club CSO	12	10	89.3
Dwr Cymru Welsh Water	Crindau Pill	Newport No33 Brynglas Rd CSO	19	9	99.3
Dwr Cymru Welsh Water	Malpas Brook	Barrack Hill CSO, Newport	19	8	99.9
Dwr Cymru Welsh Water	Liswerry Pill Reen	Liswerry Rd/Aberthaw Rd Newport ,	18	7	99.8
Dwr Cymru Welsh Water	River Ebbw	CEDAR WOOD DRIVE CSO	26	6	100
Dwr Cymru Welsh Water	River Usk Estuary	CAERLEON WWTW (STW) CSO CAERLEON	3	2	86.5
Dwr Cymru Welsh Water	Unnamed Watercour	CSO at Howe Circle	2	2	98.7
Dwr Cymru Welsh Water	Ebbw Fawr River	21 Gladstone St CSO, Crosskeys	4	1	97.5
Dwr Cymru Welsh Water	River Ebbw	WVTS - NEWBRIDGE CSO CAERPHILLY	1	1	99.9
Dwr Cymru Welsh Water	Stream To Usk	Lodge Rd CSO	1	0	94.7
Dwr Cymru Welsh Water	River Lwyd	Usk Road Pumping Station	3	0	99.9
Dwr Cymru Welsh Water	River Usk Estuary	CSO at Pill South A	2	0	99.8
Dwr Cymru Welsh Water	River Usk	Caerleon Town Sewage Pumping Station	0	0	99.9
Dwr Cymru Welsh Water	Unnamed Watercourse	Treberth Estate CSO	0	0	99.9
Dwr Cymru Welsh Water	River Ebbw Fawr	CSO at Bassaleg Forge Lane near Nos 5 & 6	0	0	100
Dwr Cymru Welsh Water	River Sirhowy	CSO at Hollybush - Ancient Druid	0	0	0
Dwr Cymru Welsh Water	River Ebbw	R/O Cobden St CSO, Crosskeys	0	0	91.5
Dwr Cymru Welsh Water	Sirhowy	WVTS-HOLLYBUSH SSO	0	0	0

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

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.

Analysing sewage pollution by the Water Industry

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