Arfon was polluted by sewage 4,354 times in 2023
lasting 31,612 hours - that's 3.66 years!

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Constituency

✔ means we have experimental daily data since 2023

Totals for Arfon in 2023

66 Sites polluted by Dwr Cymru Welsh Water

4,354 sewage dumps
31,612 h duration

That's 3.66 years! On average 11.9 times a day

Change Over Time

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Your local MP is Hywel Williams (Plaid Cymru) - Find out more about their interests, donors, and voting at They Work For You

Constituencies near Arfon

Waterways in Arfon

Pollution Summary 2023

Here are all the reported sewage overflow totals for Arfon in 2023. 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 0 of the total 69 CSO locations had reporting enabled for less than half the year, of which 0 had zero reporting.

Company	Waterway	Site	Sewage Dumps	Duration (Hours)	Reporting %
Dwr Cymru Welsh Water	River Cadnant	BETHEL SEWAGE TRANSFER PS	235	4,377	99
Dwr Cymru Welsh Water	River Ogwen	Settled Storm Overflow at Tregarth Wastewater Treatment Works	185	3,556	100
Dwr Cymru Welsh Water	River Seiont	Llanrug WwTW Settled Storm	195	3,301	91.5
Dwr Cymru Welsh Water	River Gwyrfai	CSO at Waunfawr STW	123	1,807	100
Dwr Cymru Welsh Water	River Llyfni	Nantlle PS	141	1,770	100
Dwr Cymru Welsh Water	River Seiont	Pont Rhythallt Pumping Station	181	1,695	100
Dwr Cymru Welsh Water	River Seiont	CAERNARFON WWTW STORM TANKS	153	1,336	99.9
Dwr Cymru Welsh Water	River Ogwen	BETHESDA STW (FINAL) BETHESDA	124	1,294	100
Dwr Cymru Welsh Water	River Seiont	LLANBERIS WwTW	165	1,148	100
Dwr Cymru Welsh Water	River Seiont	Storm Overflow at Penisarwaun Wastewater Treatment Works	147	1,032	99.4
Dwr Cymru Welsh Water	Gwyrfai	LLANFAGLAN WWTW FINAL EFFLUENT	91	959	100
Dwr Cymru Welsh Water	Menai Strait	Treborth WwTW (Settled Storm)	99	939	99.2
Dwr Cymru Welsh Water	Cfgin	GLASINFRYN SPS CSO	87	760	99.9
Dwr Cymru Welsh Water	River Caledffrwd	Llwyn Celyn CSO Deinolen	174	673	97
Dwr Cymru Welsh Water	Menai Strait	ABERGWYNGREGYN PUMPING STATION	30	664	99.9
Dwr Cymru Welsh Water	River Ogwen	Rock Terrace CSO Bethesda	70	467	97.1
Dwr Cymru Welsh Water	River Llyfni	Talysarn No 4 - CSO	107	453	100
Dwr Cymru Welsh Water	River Gwyrfai	Bontnewydd CSO	119	426	97.3
Dwr Cymru Welsh Water	River Ogwen	Fron Ogwen PS	69	419	95
Dwr Cymru Welsh Water	River Ogwen	BETHESDA WWTW STORM	60	392	100
Dwr Cymru Welsh Water	Un-Named Stream Into Llifon	Dorlan Goch CSO	79	352	43.3
Dwr Cymru Welsh Water	River Gwyrfai	WAUNFAWR STW (FINAL EFFLUENT)	20	350	100
Dwr Cymru Welsh Water	River Carrog	CSO at Caernarfon Hen Gastell No5	94	346	99.2
Dwr Cymru Welsh Water	River Seiont	CAERNARFON WWTW INLET PUMP ST 6MM	124	328	99.9
Dwr Cymru Welsh Water	River Gwyrfai	Llanfaglan WwTW Settled Storm Overflow	30	301	99.2
Dwr Cymru Welsh Water	River Llyfni	Llanllyfni Glan Aber CSO	152	285	97.3
Dwr Cymru Welsh Water	Rhyd	CAERNARFON - GLANRHYD SSO NO.	108	230	92
Dwr Cymru Welsh Water	Carrog	CAERNARFON - RHOSTRYFAN CSO NO	94	185	100
Dwr Cymru Welsh Water	River Caledffwrd	BRYNREFAIL MAIN SPS	44	179	99.3
Dwr Cymru Welsh Water	River Llifon	Caernarfon - Llwyn Gwalch CSO Groes	55	153	100
Dwr Cymru Welsh Water	Gwyrfai	CAERNARFON - RHOSTRYFAN CSO NO	88	151	96.2
Dwr Cymru Welsh Water	Cadnant - Caernarfon	SSO AT MILL LANE CAERNARFON	97	144	100
Dwr Cymru Welsh Water	River Gwyrfai	CSO at Bontnewydd Glanrafon No10	64	130	95.8
Dwr Cymru Welsh Water	Llyn Nantlle Uchaf	Nantlle No 5-CSO	71	126	98.8
Dwr Cymru Welsh Water	River Ogwen	RACHUB MAES BLEDDYN CSO	61	117	99.5
Dwr Cymru Welsh Water	Cegin	RHIWLAS STW	69	97	100
Dwr Cymru Welsh Water	Unknown	CSO at Tai Craig-y-don Cwymyglo	21	90	58.4
Dwr Cymru Welsh Water	Menai Straits	CROSSVILLE CSO	72	65	100
Dwr Cymru Welsh Water	River Cegin	RHIWLAS STW	28	51	100
Dwr Cymru Welsh Water	River Hwch	Llanberis CSO NO. 2	38	49	98.8
Dwr Cymru Welsh Water	Unnamed Watercourse	CAERNARFON MARGARET STREET SSO	83	46	99
Dwr Cymru Welsh Water	River Seiont	Peblig Industrial Estate CSO	31	46	99.5
Dwr Cymru Welsh Water	Goch Bach	CSO Near Castle Gift Shop Llanberis	26	44	86.3
Dwr Cymru Welsh Water	Menai Strait	BEACH ROAD PS BANGOR ,	54	42	100
Dwr Cymru Welsh Water	Menai Strait	FELINHELI PS (QUAY COTTAGE) , ,	18	40	100
Dwr Cymru Welsh Water	River Llan	CAERNARFON - PENYGROES SSO NO.	44	38	99.9
Dwr Cymru Welsh Water	Menai Strait	TREBORTH STW (FINAL) BANGOR	15	28	99.3
Dwr Cymru Welsh Water	Menai Strait	Gorad Road SPS	27	18	100
Dwr Cymru Welsh Water	River Cadnant	BETHEL CSO BETHEL NEAR CAERNARFON	14	18	99.6
Dwr Cymru Welsh Water	Cadnant	BETHEL SSO NO. 3	8	16	100
Dwr Cymru Welsh Water	River Y Llan	LLANLLECHID SPS , ,	2	12	100
Dwr Cymru Welsh Water	River Ogwen	TALYBONT STW	6	12	100
Dwr Cymru Welsh Water	Llyn Padarn	LLANBERIS PS , ,	10	11	99.7
Dwr Cymru Welsh Water	River Seiont	Caernarfon WWTW Inlet Pump ST 6mm SPS	16	9	99.9
Dwr Cymru Welsh Water	Cadnant	MIN-Y-NANT CSO	17	8	99.9
Dwr Cymru Welsh Water	Menai Strait	COLEG NORMAL SEWAGE PUMPING STATION	5	3	99.9
Dwr Cymru Welsh Water	River Gwyrfai	Bontnewydd CSO Ysgol Gynradd Bontne	2	1	99.9
Dwr Cymru Welsh Water	River Siont	ANGLESEY ARMS PUMPING STATION	1	1	93.5
Dwr Cymru Welsh Water	Cadnant	BETHEL SSO NO. 2	4	1	99.9
Dwr Cymru Welsh Water	Seiont	CAERNARFON PONT SEIONT PS	1	0	98.7
Dwr Cymru Welsh Water	Menai Strait	FELINHELI PS (OPP SEA CADET CORPS)	1	0	100
Dwr Cymru Welsh Water	Menai Strait	FELINHELI PS (ADJ TO QUAY TOILETS)	1	0	100
Dwr Cymru Welsh Water	Menai Straits	BALACLAVA ROAD SEWAGE PUMPING ST	1	0	98.6
Dwr Cymru Welsh Water	Menai Strait	WATERLOO PORT SEWAGE PUMPING ST	1	0	99.8
Dwr Cymru Welsh Water	Menai Straits	CAERNARFON BANK QUAY PS	1	0	98.1
Dwr Cymru Welsh Water	Estuarial Waters	Meirion Road PS (Storm/Emerg)	1	0	100
Dwr Cymru Welsh Water	River Cegin	GLAENTRAETH ESTATE PS BANGOR ,	0	0	99.7
Dwr Cymru Welsh Water	River Llyfni	Talysarn No 3 - CSO	0	0	94.8
Dwr Cymru Welsh Water	River Caledffrwd	CSO at Pen yr Olchfa Clwt Y Bont Deiniolen	0	0	12.8

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. This 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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