Area of Outstanding Natural Beauty

Clwydian Range & Dee Valley - 2025 Sewage

Polluted by sewage 1,928 hours in 2025

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

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Totals for Clwydian Range & Dee Valley in 2025

Sewage1,928 hours
Monitoring offline0 hours
Potential pollution0 hours
Storm overflows23

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Daily Data - when it rained, and when they spilled

Square = rainfall none → heavy
Drop = sewage minutes → all day
Potential pollution Monitoring offline
Jan - 0 hours
Feb - 86 hours
Mar - 67 hours
Apr - 23 hours
May - 3 hours
Jun - 55 hours
Jul - 38 hours
Aug - 40 hours
Sept - 247 hours
Oct - 73 hours
Nov - 651 hours
Dec - 642 hours

Storm overflows in and around Clwydian Range & Dee Valley

Company Site Name Receiving Waterway Overflow Days Total Duration (hours) Offline/Potential Pollution
Dwr Cymru Welsh Water Corwen WwTW Storm Overflow River Dee 43 486h 3m -
Dwr Cymru Welsh Water Llangollen WwTW Storm Overflow River Dee 37 311h 54m -
Dwr Cymru Welsh Water Outside Corwen WwTW Storm Overflow Unnamed Stream 63 267h 6m -
Dwr Cymru Welsh Water Cefn Mawr WwTW Storm Overflow River Dee 36 183h 18m -
Dwr Cymru Welsh Water Llangollen Queen Street Storm Overflow River Cyflymen 40 164h 13m -
Dwr Cymru Welsh Water Cefn Storm Overflow Tref-Y-Nant Brook 39 113h 34m -
Dwr Cymru Welsh Water Abbey Road Storm Overflow River Dee 33 98h 3m -
Dwr Cymru Welsh Water Llanarmon Yn Ial WwTW Overflow River Alyn 38 74h 41m -
Dwr Cymru Welsh Water Nannerch Storm Overflow Tributary of River Wheeler 8 62h 45m -
Dwr Cymru Welsh Water Bridge Street No 2 Storm Overflow River Dee 31 54h 19m -
Dwr Cymru Welsh Water Llangollen West Street Storm Overflow River Dee 7 35h 25m -
Dwr Cymru Welsh Water Llanferres Storm Overflow Tributary of Afon Alun 5 35h 17m -
Dwr Cymru Welsh Water Off Church Terrace Llandegla Storm Overflow River Alyn 6 14h 14m -
Dwr Cymru Welsh Water Next to Bridge Newbridge Overflow River Dee 5 11h -
Dwr Cymru Welsh Water Northern Terrace Corwen Storm Overflow River Dee 3 8h 28m -
Dwr Cymru Welsh Water Church Road Minera Storm Overflow Afon Clywedog 6 2h 15m -
Dwr Cymru Welsh Water Bridge Street Storm Overflow No1 River Dee 2 1h 55m -
Dwr Cymru Welsh Water Berwyn Street Storm Overflow River Dee via surface water sewer 2 1h 45m -
Dwr Cymru Welsh Water Llangollen East Street Storm Overflow River Dee 4 1h 15m -
Dwr Cymru Welsh Water Llangollen Church Street Storm Overflow River Dee 1 1h 14m -
Dwr Cymru Welsh Water Llangollen Riverside Park Storm Overflow River Dee 0 0h -
Dwr Cymru Welsh Water Llangollen Victoria Prom Storm Overflow River Dee 0 0h -
Dwr Cymru Welsh Water Park Avenue Storm Overflow River Dee 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.