Monmouthshire - 2025 Sewage

Polluted by sewage 18,319 hours in 2025 - That's 2.12 years

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

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View Annual Sewage Data

You're looking at the totals that we have calculated for sewage in Monmouthshire 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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Constituencies near Monmouthshire

Daily Data

We get information about overflowing CSOs since January 2025. Here is a chart of the last three months of data for Monmouthshire, 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 Pwllmeyric Storm Overflow Mounton Brook 148 3,200 h 20m 133.33
Dwr Cymru Welsh Water Usk WwTW Storm Overflow River Usk 119 2,511 h 49m 104.62
Dwr Cymru Welsh Water Little Mill WwTW Overflow Berthin Brook 77 1,459 h 45m 60.79
Dwr Cymru Welsh Water Castell Coch Overflow Mill Reen 111 1,405 h 22m 58.54
Dwr Cymru Welsh Water Hunger Pill Overflow River Wye Estuary 99 1,387 h 34m 57.79
Dwr Cymru Welsh Water Goytre WwTW Storm Overflow River Usk 71 885 h 22m 36.88
Dwr Cymru Welsh Water Llangybi WwTW Storm Overflow River Usk 126 868 h 15m 36.17
Dwr Cymru Welsh Water Welsh Street Storm Overflow River Wye 100 795 h 50m 33.12
Dwr Cymru Welsh Water Forge Hammer Storm Overflow River Clydach 73 760 h 30m 31.67
Dwr Cymru Welsh Water Pandy WwTW Inlet Overflow. River Honddu 48 726 h 15m 30.25
Dwr Cymru Welsh Water Pentraeth WwTW Storm Overflow Afon Nodwydd 56 723 h 30m 30.12
Dwr Cymru Welsh Water Aberbaiden WwTW Inlet Storm Overflow River Usk 75 520 h 6m 21.67
Dwr Cymru Welsh Water Bryngwenin Overflow Mynachdy Brook 25 389 h 44m 16.21
Dwr Cymru Welsh Water Llanfoist WwTW Storm Overflow River Usk 54 383 h 30m 15.96
Dwr Cymru Welsh Water Caravan Park Clydach Storm Overflow River Clydach 42 370 h 15.42
Dwr Cymru Welsh Water Great Oak WwTW Storm Overflow Tributary of Clawdd Brook 28 339 h 15m 14.12
Dwr Cymru Welsh Water Tintern Main Road Storm Overflow River Wye 15 285 h 47m 11.88
Dwr Cymru Welsh Water Chepstow Fairfield Storm Overflow River Wye Estuary 66 281 h 53m 11.71
Dwr Cymru Welsh Water Wyesham Monmouth WwTW Storm Overflow River Wye 31 231 h 30m 9.62
Dwr Cymru Welsh Water Mill Street Castle Meadows Storm Overflow River Usk 50 194 h 15m 8.08
Dwr Cymru Welsh Water Mathern Storm Overflow Tributary of Mounton Brook 14 128 h 50m 5.33
Dwr Cymru Welsh Water Granville Street Riverbank Storm Overflow River Wye 27 95 h 30m 3.96
Dwr Cymru Welsh Water Little Mill Storm Overflow Berthin Brook 19 93 h 30m 3.88
Dwr Cymru Welsh Water Chepstow North Storm Overflow River Wye Estuary 43 55 h 45m 2.29
Dwr Cymru Welsh Water Thornwell Road Storm Overflow River Wye 36 53 h 30m 2.21
Dwr Cymru Welsh Water Mill Lane Usk Overflow River Usk 32 46 h 40m 1.92
Dwr Cymru Welsh Water Glangrwyney Road Storm Overflow River Clydach 16 33 h 57m 1.38
Dwr Cymru Welsh Water Tintern WwTW Overflow River Wye 22 22 h 56m 0.92
Dwr Cymru Welsh Water Unknown Unknown 3 18 h 15m 0.75
Dwr Cymru Welsh Water Blestium Street Monmouth Storm Overflow River Monnow 12 12 h 45m 0.5
Dwr Cymru Welsh Water Raglan WwTW Storm Overflow Nant Y Wilcae 9 10 h 45m 0.42
Dwr Cymru Welsh Water Raglan Way Storm Overflow River Wye 11 9 h 14m 0.38
Dwr Cymru Welsh Water Bluebell Drive Overflow River Wye 1 7 h 30m 0.29
Dwr Cymru Welsh Water West of Barton Bridge Storm Overflow Tributary of Nant Wilcae 5 5 h 43m 0.21
Dwr Cymru Welsh Water Cwrt Bryn Derwen Storm Overflow Olway Brook 1 2 h 45m 0.08
Dwr Cymru Welsh Water Magor Storm Overflow Severn Estuary 4 1 h 0.04
Dwr Cymru Welsh Water Unknown Unknown 0 0 h 0
Dwr Cymru Welsh Water South Hillcrest Road Monmouth Overflow River Wye 0 0 h 0
Dwr Cymru Welsh Water Caldicot Storm Overflow Severn Estuary 0 0 h 0
Dwr Cymru Welsh Water North Hillcrest Road Monmouth Overflow River Wye 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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© 2020-2025 Top-Of-The-Poops CC-BY-SA 4.0,
© Openstreetmap contributors, Contains OS data © Crown copyright and database right 2021-2025,
Contains Water UK National Storm Overflow Hub Data CC-BY-SA 4.0 and analysis © 2025 Top-Of-The-Poops

Some data reproduced under Open Government Licence

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