Dwyfor Meirionnydd - 2025 Sewage

Polluted by sewage 79,173 hours in 2025 - That's 9.16 years

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

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You're looking at the totals that we have calculated for sewage in Dwyfor Meirionnydd for 2025. It is an estimate, based on very poor quality live data from the Water Companies. This may not align with the 'official' reported sewage values from the water companies, which is reported in April following then end of the year - so 2025 numbers are reported in April 2026.

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Daily Data

We get information about overflowing CSOs since January 2025. Here is a chart of the last three months of data for Dwyfor Meirionnydd, 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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Daily data is experimental and data is not guaranteed to be accurate. Please inform us of any issue, we will fix.
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Totals so far

Company Site Name Receiving Waterway Overflow Days Total Duration (hours) Total Duration (days)
Dwr Cymru Welsh Water Llan Ffestiniog WwTW Inlet Storm Overflow Nant Brisgyll 282 3,109 h 29m 129.54
Dwr Cymru Welsh Water Llangybi WwTW Overflow River Erch 162 3,089 h 15m 128.71
Dwr Cymru Welsh Water Blaenau Ffestiniog WwTW Point 1 Storm Overflow Afon Goedol 131 2,276 h 14m 94.83
Dwr Cymru Welsh Water Abererch WwTW Storm Overflow River Erch 116 2,238 h 38m 93.25
Dwr Cymru Welsh Water Beddgelert WwTW Storm Overflow River Glaslyn 137 2,099 h 12m 87.46
Dwr Cymru Welsh Water Fairbourne WwTW Storm Overflow Coastal Waters 102 2,025 h 30m 84.38
Dwr Cymru Welsh Water Four Crosses WwTW Storm Overflow River Erch 186 1,917 h 45m 79.88
Dwr Cymru Welsh Water Llanaelhaearn WwTW Overflow Unnamed Watercourse 196 1,911 h 57m 79.62
Dwr Cymru Welsh Water Chwilog WwTW Storm Overflow Afon Wen 111 1,786 h 30m 74.42
Dwr Cymru Welsh Water Trefor WwTW Relief Discharge Point Storm Overflow Unnamed Watercourse 123 1,650 h 57m 68.75
Dwr Cymru Welsh Water Nefyn Storm Overflow Caernarfon Bay 105 1,584 h 44m 66
Dwr Cymru Welsh Water Llithfaen WwTW Storm Overflow Rhyd Hir 78 1,552 h 45m 64.67
Dwr Cymru Welsh Water Criccieth WwTW Storm Overflow Tremadog Bay 89 1,491 h 30m 62.12
Dwr Cymru Welsh Water Llanllyfni WwTW Storm Overflow River Llynfi 108 1,489 h 15m 62.04
Dwr Cymru Welsh Water Llanelltyd Storm Overflow River Mawddach 75 1,396 h 11m 58.17
Dwr Cymru Welsh Water Llanrug WwTW Storm Overflow Afon Seiont 87 1,384 h 37m 57.67
Dwr Cymru Welsh Water Dolgellau WwTW Storm Overflow River Mawddach 77 1,229 h 59m 51.21
Dwr Cymru Welsh Water Llanystumdwy WwTW Settled Storm Overflow Dwyfor River 70 1,209 h 30m 50.38
Dwr Cymru Welsh Water Garndolbenmaen WwTW Storm Overflow Afon Dwyfor 77 1,190 h 30m 49.58
Dwr Cymru Welsh Water Station Road Pontrhythallt Storm Overflow River Seiont 104 1,152 h 26m 48
Dwr Cymru Welsh Water Waunfawr WwTW Storm Overflow Afon Gwyrfai 72 1,111 h 45m 46.29
Dwr Cymru Welsh Water Trawsfynydd WwTW Storm Overflow Afon Prysor 91 1,110 h 54m 46.25
Dwr Cymru Welsh Water Llanberis WwTW Storm Overflow Afon y Bala 97 938 h 45m 39.08
Dwr Cymru Welsh Water Corris WwTW Storm Overflow Afon Dulas 78 900 h 34m 37.5
Dwr Cymru Welsh Water B4418 Caernarfon Storm Overflow River Llynfi 64 895 h 15m 37.29
Dwr Cymru Welsh Water Penmaenpool Bridge Storm Overflow River Mawddach 83 895 h 37.29
Dwr Cymru Welsh Water Dyffryn Ardudwy WwTW Storm Overflow Ardudwy Marsh Main Drain 62 879 h 15m 36.62
Dwr Cymru Welsh Water Aberdyfi Storm Overflow River Dyfi 47 875 h 31m 36.46
Dwr Cymru Welsh Water Llanfaglan WwTW Storm Overflow Afon Gwyrfai 65 869 h 29m 36.21
Dwr Cymru Welsh Water Harlech Main High Level Storm Overflow Unnamed Watercourse 46 864 h 6m 36
Dwr Cymru Welsh Water Cwm Bowydd Blaenau Ffestiniog Storm Overflow Afon Bowydd 92 824 h 59m 34.33
Dwr Cymru Welsh Water Efailnewydd WwTW Storm Overflow Unnamed Tributary of the Afon Rhyd Hir 90 812 h 44m 33.83
Dwr Cymru Welsh Water Llan Ffestiniog WwTW Settled Storm Overflow Nant Brisgyll 93 803 h 15m 33.46
Dwr Cymru Welsh Water Penisarwaun WwTW Storm Overflow Afon Seiont 105 802 h 30m 33.42
Dwr Cymru Welsh Water Mynytho WwTW Storm Overflow Unnamed Watercourse 88 779 h 55m 32.46
Dwr Cymru Welsh Water Bron Castell Storm Overflow Unnamed Watercourse 42 758 h 53m 31.58
Dwr Cymru Welsh Water Cambrian View Penrhyndeudraeth Storm Overflow Tributary of Afon Dwyryd 99 748 h 45m 31.17
Dwr Cymru Welsh Water Unknown Unknown 37 724 h 48m 30.17
Dwr Cymru Welsh Water Nefyn WwTW Inlet PS (Discharge Point A) Storm Overflow Afon Geirch 80 724 h 45m 30.17
Dwr Cymru Welsh Water Llannor WwTW Storm Overflow Afon Rhyd Hir 83 703 h 24m 29.29
Dwr Cymru Welsh Water Llanuwchllyn WwTW Overflow Afon Twrch 85 699 h 15m 29.12
Dwr Cymru Welsh Water Maentwrog WwTW Storm Overflow River Dwyryd 52 693 h 30m 28.88
Dwr Cymru Welsh Water Pentrefelin WwTW Storm Overflow Afon Cedron 59 692 h 28.83
Dwr Cymru Welsh Water Lôn Goch Edern Storm Overflow Afon Geirch 60 681 h 17m 28.38
Dwr Cymru Welsh Water Llanystumdwy WwTW Storm Overflow Dwyfor River 64 661 h 45m 27.54
Dwr Cymru Welsh Water Talysarn Gas Works Storm Overflow Unnamed Tribuatary of Afon Llyfni 63 633 h 52m 26.38
Dwr Cymru Welsh Water Bontddu WwTW Storm Overflow Afon Cwmllechen 61 616 h 6m 25.67
Dwr Cymru Welsh Water Church Street Llanuwchllyn Storm Overflow River Dee 49 613 h 22m 25.54
Dwr Cymru Welsh Water Barmouth WwTW Long Sea Storm Overflow Cardigan Bay 136 579 h 45m 24.12
Dwr Cymru Welsh Water Glanypwll Road Storm Overflow Afon Barlwyd 112 572 h 48m 23.83
Dwr Cymru Welsh Water Bronaber WwTW Storm Overflow River Eden 63 545 h 9m 22.71
Dwr Cymru Welsh Water Llanbedrog Long Nant-Iago Storm Overflow Tremadog Bay 35 534 h 22.25
Dwr Cymru Welsh Water Stad Hafod Deiniolen Storm Overflow Afon Caledffrwd 104 526 h 11m 21.92
Dwr Cymru Welsh Water Castell Arthog Storm Overflow Unnamed Watercourse 40 522 h 30m 21.75
Dwr Cymru Welsh Water Pencefn Road Tanygrisiau Storm Overflow Afon Goedol 67 514 h 40m 21.42
Dwr Cymru Welsh Water Gellilydan WwTW Settled Storm Overflow Tributary of the Afon Tafarn Helyg 67 513 h 30m 21.38
Dwr Cymru Welsh Water South of River Bontnewydd Storm Overflow Afon Gwyrfai 73 504 h 18m 21
Dwr Cymru Welsh Water Talysarn Bridge Storm Overflow Unnamed Tribuatary of Afon Llyfni 67 486 h 17m 20.25
Dwr Cymru Welsh Water Corwen WwTW Storm Overflow River Dee 43 486 h 3m 20.25
Dwr Cymru Welsh Water Talsarnau WwTW Storm Overflow Unnamed Watercourse 53 467 h 46m 19.46
Dwr Cymru Welsh Water Bethel Storm Overflow Tributary of Afon Cadnant 48 456 h 50m 19
Dwr Cymru Welsh Water Pontllyfni No 3 Storm Overflow River Llyfni 35 455 h 15m 18.96
Dwr Cymru Welsh Water Taleymerau Pwllheli Storm Overflow Afon Rhyd Hir 57 443 h 49m 18.46
Dwr Cymru Welsh Water Llandrillo Storm Overflow Afon Ceidiog 68 436 h 19m 18.17
Dwr Cymru Welsh Water West Parade Criccieth Overflow Tremadog Bay 43 401 h 16.71
Dwr Cymru Welsh Water Caernarfon Hen Gastell Storm Overflow Afon Carrog 60 392 h 30m 16.33
Dwr Cymru Welsh Water West Parade Criccieth Storm Overflow Tremadog Bay 32 384 h 42m 16
Dwr Cymru Welsh Water Bala WwTW Storm Overflow River Dee 61 380 h 45m 15.83
Dwr Cymru Welsh Water East Bank Afon Glaslyn Beddgelert Storm Overflow River Glaslyn 43 376 h 44m 15.67
Dwr Cymru Welsh Water Congl Y Wal Blaenau Ffestiniog Storm Overflow Storm Overflow Afon Ceunant Sych 35 363 h 51m 15.12
Dwr Cymru Welsh Water Criccieth East Overflow Tremadog Bay 47 361 h 40m 15.04
Dwr Cymru Welsh Water Arthog Terrace Storm Overflow Unnamed Watercourse 37 355 h 15m 14.79
Dwr Cymru Welsh Water Tywyn WwTW Settled Storm Overflow Coastal Water - Cardigan Bay 68 353 h 30m 14.71
Dwr Cymru Welsh Water Esplanade Criccieth Storm Overflow Tremadog Bay 27 335 h 13.96
Dwr Cymru Welsh Water Nefyn WwTW Settled Storm Overflow Unnamed Tributary of Afon Geirch 25 327 h 32m 13.62
Dwr Cymru Welsh Water Tywyn WwTW Storm Overflow Dysynni Low Level Drainage Channel 60 325 h 15m 13.54
Dwr Cymru Welsh Water Clynnog Fawr Storm Overflow Unnamed Stream 54 313 h 30m 13.04
Dwr Cymru Welsh Water Llandanwg Station Storm Overflow Tremadog Bay 22 306 h 43m 12.75
Dwr Cymru Welsh Water Dolgellau Marian Mawr Storm Overflow River Wnion 76 291 h 15m 12.12
Dwr Cymru Welsh Water Caernarfon WwTW Storm Overflow Afon Seiont - Lower 71 271 h 15m 11.29
Dwr Cymru Welsh Water Outside Corwen WwTW Storm Overflow Unnamed Stream 63 265 h 16m 11.04
Dwr Cymru Welsh Water Glanrafon Bontnewydd Storm Overflow Afon Gwyrfai 28 264 h 37m 11
Dwr Cymru Welsh Water Caernarfon WwTW Storm Tank Storm Overflow Afon Seiont 24 262 h 49m 10.92
Dwr Cymru Welsh Water Bryncir WwTW Storm Overflow Afon Blaen-y-cae 40 248 h 30m 10.33
Dwr Cymru Welsh Water Marian Mawr Dolgellau Storm Overflow Ffos Ddu 23 244 h 41m 10.17
Dwr Cymru Welsh Water Brynrefail Main Storm Overflow Afon Caledffrwd 41 242 h 51m 10.08
Dwr Cymru Welsh Water Point B Nefyn WwTW Inlet Storm Overflow River Ceirch 62 241 h 55m 10.04
Dwr Cymru Welsh Water Llanllyfni Glan Aber Storm Overflow River Loughor 77 226 h 13m 9.42
Dwr Cymru Welsh Water Heulfryn Llanfaglan Storm Overflow Afon Carrog 62 223 h 51m 9.29
Dwr Cymru Welsh Water Rhiwlas WwTW Storm Overflow Afon Cegin 72 217 h 57m 9.04
Dwr Cymru Welsh Water Snowdon Street Storm Overflow Cyt Bach 58 205 h 15m 8.54
Dwr Cymru Welsh Water Nantlle No 5 Caernarfon Storm Overflow Llyn Nantlle Uchaf 46 204 h 5m 8.5
Dwr Cymru Welsh Water Cynwyd WwTW Storm Overflow River Dee 57 196 h 17m 8.17
Dwr Cymru Welsh Water Llwyngwril Storm Overflow Coastal Waters - Barmouth Bay 25 191 h 6m 7.96
Dwr Cymru Welsh Water Pen Y Cefn Road Storm Overflow River Wnion 38 180 h 45m 7.5
Dwr Cymru Welsh Water Rhosgadfan Storm Overflow Gwyrfai 43 176 h 7m 7.33
Dwr Cymru Welsh Water Abergynolwyn WwTW Storm Overflow River Dysynni 28 172 h 5m 7.17
Dwr Cymru Welsh Water Carmel Groeslon Fields Storm Overflow Afon Llifon 52 168 h 21m 7
Dwr Cymru Welsh Water Morfa Bychan WwTW Storm Overflow Coastal Waters 39 162 h 6.75
Dwr Cymru Welsh Water Aberdesach Storm Overflow Afon Desach 57 153 h 15m 6.38
Dwr Cymru Welsh Water Mill Lane Caernarfon Storm Overflow Afon Cadnant 66 151 h 30m 6.29
Dwr Cymru Welsh Water Llanwnda Storm Overflow Rhyd 38 150 h 38m 6.25
Dwr Cymru Welsh Water Fford Morfa Bychan Storm Overflow Tributary of Afon Glaslyn 58 143 h 40m 5.96
Dwr Cymru Welsh Water Caernarfon Seiont Bridge Storm Overflow River Seiont 15 139 h 49m 5.79
Dwr Cymru Welsh Water Hen Gei Llechi Felinheli Main Overflow Menai Strait 19 134 h 5.58
Dwr Cymru Welsh Water Bryncoch Storm Overflow Unnamed Watercourse 12 130 h 30m 5.42
Dwr Cymru Welsh Water Llanberis Maes Padarn Storm Overflow Goch Bach 32 122 h 32m 5.08
Dwr Cymru Welsh Water Borth-Y-Gest Storm Overflow River Glaslyn 29 120 h 34m 5
Dwr Cymru Welsh Water Llwyn-y-gwalch Storm Overflow Afon Llifon 48 113 h 45m 4.71
Dwr Cymru Welsh Water Alyn Road Fairbourne Storm Overflow Afon Henddol 18 113 h 30m 4.71
Dwr Cymru Welsh Water Abersoch Harbour Storm Overflow Afon Soch Estuary 10 101 h 30m 4.21
Dwr Cymru Welsh Water North of River Bontnewydd Storm Overflow Afon Gwyrfai 37 101 h 30m 4.21
Dwr Cymru Welsh Water Unknown Unknown 97 100 h 4m 4.17
Dwr Cymru Welsh Water Dôl Eilian Llanberis Storm Overflow Afon Hwch 28 93 h 36m 3.88
Dwr Cymru Welsh Water Llanbedr WwTW Storm Overflow Afon Artro 23 82 h 18m 3.42
Dwr Cymru Welsh Water Llanegryn Street Storm Overflow River Dysynni 25 81 h 30m 3.38
Dwr Cymru Welsh Water Penrhos Camp WwTW Storm Overflow Afon Penrhos 28 80 h 24m 3.33
Dwr Cymru Welsh Water Tai Craig Y Don Cwm Y Glo Storm Overflow Unknown 14 80 h 19m 3.33
Dwr Cymru Welsh Water B4419 Caernarfon Storm Overflow Menai Strait 55 77 h 36m 3.21
Dwr Cymru Welsh Water Idris Villas to NRA Storm Overflow Ditch 31 67 h 15m 2.79
Dwr Cymru Welsh Water Maes Gwyndy Trawsfynydd Storm Overflow Afon Prysor 43 67 h 12m 2.79
Dwr Cymru Welsh Water Lombard Street Bank Place Porthmadog Storm Overflow Unnamed Stream 41 57 h 13m 2.38
Dwr Cymru Welsh Water Tan Y Buarth Bethel Storm Overflow Afon Cadnant 20 55 h 13m 2.29
Dwr Cymru Welsh Water Y Maes Pwllheli Storm Overflow Estuarial Waters of Afon Rhyd Hir 24 54 h 30m 2.25
Dwr Cymru Welsh Water Aberdaron Storm Overflow Afon Daron 20 53 h 15m 2.21
Dwr Cymru Welsh Water Caernarfon Llanbeblig Road Storm Overflow Afon Seiont 30 52 h 57m 2.17
Dwr Cymru Welsh Water Penygroes Storm Overflow River Llynfi 17 47 h 1.96
Dwr Cymru Welsh Water Tremadog Iscraig Storm Overflow Y Cyt 11 47 h 1.96
Dwr Cymru Welsh Water Unknown Unknown 5 44 h 15m 1.83
Dwr Cymru Welsh Water Porthmadog WwTW Final Effluent Overflow Glaslyn Estuary within Glaslyn Marshes 6 43 h 45m 1.79
Dwr Cymru Welsh Water Market Street Llanberis Storm Overflow Llyn Padarn 12 41 h 36m 1.71
Dwr Cymru Welsh Water Tregof Bethel Storm Overflow Afon Cadnant 11 40 h 20m 1.67
Dwr Cymru Welsh Water Pontllyfni STW Storm Overflow River Llyfni 18 38 h 1.58
Dwr Cymru Welsh Water Glasfryn Terrace Storm Overflow Unnamed Watercourse 4 36 h 45m 1.5
Dwr Cymru Welsh Water Wesleyan Terrace Storm Overflow Unnamed Watercourse 5 34 h 45m 1.42
Dwr Cymru Welsh Water Porthmadog Britannia Place Storm Overflow River Glaslyn 4 34 h 30m 1.42
Dwr Cymru Welsh Water Penrhyndeudraeth WwTW Settled Storm Overflow River Dwyryd 6 32 h 13m 1.33
Dwr Cymru Welsh Water Margret Street Storm Overflow Afon Cadnant 37 29 h 43m 1.21
Dwr Cymru Welsh Water Trefor Storm Overflow Unnamed Stream 14 25 h 1m 1.04
Dwr Cymru Welsh Water Barmouth WwTW Short Sea Storm Overflow Cardigan Bay 16 20 h 45m 0.83
Dwr Cymru Welsh Water Llwyn Y Gell Road Ffestiniog Storm Overflow Barlwydd 11 17 h 45m 0.71
Dwr Cymru Welsh Water Friogg Storm Overflow Unnamed Watercourse 8 17 h 30m 0.71
Dwr Cymru Welsh Water Fronwynion Street Trawsfynydd Storm Overflow Afon Prysor 11 16 h 58m 0.67
Dwr Cymru Welsh Water Afonwen WwTW Storm Overflow Afon Wen 3 15 h 31m 0.62
Dwr Cymru Welsh Water Llandanwg Storm Overflow Tremadog Bay 2 14 h 7m 0.58
Dwr Cymru Welsh Water Aberdaron WwTW Storm Overflow Afon Cylch-y-Felin 12 13 h 45m 0.54
Dwr Cymru Welsh Water Ffordd Penllach Storm Overflow Unnamed Stream 13 13 h 23m 0.54
Dwr Cymru Welsh Water East Llanelltyd Storm Overflow River Mawddach 10 11 h 24m 0.46
Dwr Cymru Welsh Water North Western Road Blaenau Ffestiniog Overflow Afon Goedol 8 8 h 45m 0.33
Dwr Cymru Welsh Water Northern Terrace Corwen Storm Overflow River Dee 3 7 h 59m 0.29
Dwr Cymru Welsh Water Beach Bank Criccieth Storm Overflow Culverted stream which crosses Criccieth Beach 5 7 h 42m 0.29
Dwr Cymru Welsh Water Llanberis Road Storm Overflow Afon Cadnant 13 7 h 0.29
Dwr Cymru Welsh Water Stryd Y Felin Storm Overflow Unnamed Watercourse 12 6 h 21m 0.25
Dwr Cymru Welsh Water A470 A4212 Junction Storm Overflow Unnamed Stream 11 5 h 32m 0.21
Dwr Cymru Welsh Water Barmouth Harbour Storm Overflow Mawddach Estuary 8 4 h 30m 0.17
Dwr Cymru Welsh Water Llanfachreth WwTW Storm Overflow Afon y Llan 8 4 h 15m 0.17
Dwr Cymru Welsh Water Clwt-y-bont Storm Overflow Afon Caledffrwd 4 4 h 13m 0.17
Dwr Cymru Welsh Water Porthmadog WwTW Site Drainage Overflow Glaslyn Estuary 3 2 h 45m 0.08
Dwr Cymru Welsh Water Porthmadog WwTW Tank Overflow Glaslyn Estuary 2 2 h 19m 0.08
Dwr Cymru Welsh Water Minffordd Street Corris Storm Overflow River Deri 3 1 h 59m 0.04
Dwr Cymru Welsh Water Harlech Storm Overflow Tributary of Afon Dwyryd 7 1 h 59m 0.04
Dwr Cymru Welsh Water Chapel Street Porthmadog Storm Overflow Nant Y Cyt 1 1 h 29m 0.04
Dwr Cymru Welsh Water Glan-Y-Don Pwllheli Storm Overflow River Erch 3 1 h 28m 0.04
Dwr Cymru Welsh Water Maentwrog Storm Overflow River Dwyryd 4 0 h 59m 0
Dwr Cymru Welsh Water Ysgoldy Storm Overflow Afon Cadnant 3 0 h 52m 0
Dwr Cymru Welsh Water Mawddach Crescent Storm Overflow Mawddach Estuary 2 0 h 40m 0
Dwr Cymru Welsh Water Caernarfon WwTW Inlet Storm Overflow River Seiont 2 0 h 30m 0
Dwr Cymru Welsh Water Amanda Terrace Storm Overflow River Glaslyn Estuary 2 0 h 30m 0
Dwr Cymru Welsh Water Rhedyw Road Llanllyfni Overflow River Llynfi 2 0 h 29m 0
Dwr Cymru Welsh Water A496 Llanbedr Storm Overflow Culvert to Afon Artro 1 0 h 15m 0
Dwr Cymru Welsh Water St. Mary's Terrace Storm Overflow Unnamed Watercourse 1 0 h 15m 0
Dwr Cymru Welsh Water The Square Blaenau Ffestiniog Storm Overflow Afon Bowydd 1 0 h 15m 0
Dwr Cymru Welsh Water Chandlers Place Porthmadog Storm Overflow Nant Y Cyt 1 0 h 15m 0
Dwr Cymru Welsh Water Bank Quay Caernarfon Storm Overflow Menai Strait 0 0 h 0
Dwr Cymru Welsh Water Unknown Unknown 0 0 h 0
Dwr Cymru Welsh Water Unknown Unknown 0 0 h 0
Dwr Cymru Welsh Water Bryncrug Overflow Afon Fathew 0 0 h 0
Dwr Cymru Welsh Water Bridge on A499 Pontllyfni Overflow River Llyfni 0 0 h 0
Dwr Cymru Welsh Water Crown Street Caernarfon Overflow Menai Strait 0 0 h 0
Dwr Cymru Welsh Water Glan Y Mor Felinheli Overflow Menai Strait 0 0 h 0
Dwr Cymru Welsh Water Morfa Bychan WwTW High-level Storm Overflow Unnamed Stream 0 0 h 0
Dwr Cymru Welsh Water Unknown Unknown 0 0 h 0
Dwr Cymru Welsh Water Castle Ditch Storm Overflow Afon Seiont 0 0 h 0
Dwr Cymru Welsh Water Afon Angell Bridge Aberangell Storm Overflow Afon Angell 0 0 h 0
Dwr Cymru Welsh Water Corwen Clawdd Poncefn Storm Overflow Tributary of River Dee 0 0 h 0
Dwr Cymru Welsh Water Abererch Road Crossing Storm Overflow River Erch 0 0 h 0
Dwr Cymru Welsh Water Unknown Unknown 0 0 h 0
Dwr Cymru Welsh Water Unknown Unknown 0 0 h 0
Dwr Cymru Welsh Water Waterloo Port Road Storm Overflow Menai Strait 0 0 h 0
Dwr Cymru Welsh Water Port Terrace Felinheli Overflow Menai Strait 0 0 h 0
Dwr Cymru Welsh Water Blaenau Ffestiniog WwTW Point 2 Storm Overflow Afon Bowydd 0 0 h 0
Dwr Cymru Welsh Water Unknown Unknown 0 0 h 0
Dwr Cymru Welsh Water Unknown Unknown 0 0 h 0
Dwr Cymru Welsh Water Balaclava Road Caernarfon Storm Overflow Menai Strait 0 0 h 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.

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Contains Water UK National Storm Overflow Hub Data CC-BY-SA 4.0 and analysis © 2025 Top-Of-The-Poops

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