It's a Dirty Business

Watch Channel 4's documentary about the state of the water industry, then sign the petition to bring water back to public ownership.

Monmouthshire - 2025 Sewage

Polluted by sewage 18,381 hours in 2025 - That's 2.13 years

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

Which Year?

Select Another Constituency

Select the constituency from the drop-down
✔ means we have live data (𝑥 if not)

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.

What's a potential overflow? If the CSO goes 'Offline' while its Overflowing, we don't know if it stopped overflowing until we get a 'Stop' event.

Take Action

Your local MP is Catherine Fookes (Labour) - Find out more about their interests, donors, and voting at They Work For You

Share this page, post a message, and tell others about the huge problem of sewage pollution across the UK
Post
Post

Constituencies near Monmouthshire

Daily Data

Jan - 0 hours
Feb - 1,622 hours
Mar - 1,565 hours
Apr - 475 hours
May - 21 hours
Jun - 251 hours
Jul - 98 hours
Aug - 116 hours
Sept - 1,364 hours
Oct - 2,046 hours
Nov - 4,800 hours
Dec - 5,954 hours
Daily data is experimental and data is not guaranteed to be accurate. Please inform us of any issue, we will fix.
Please note: We don't have rainfall data for Wales. If you know where to source it please let us know!
We need your support!

Please consider a one-off or small recurring donation. We need your help to keep this site going.

Donate Now

Totals so far

Company Site Name Receiving Waterway Overflow Days Total Duration (hours) Offline/Potential Pollution
Dwr Cymru Welsh Water Pwllmeyric Storm Overflow Mounton Brook 149 3,223h 45m -
Dwr Cymru Welsh Water Usk WwTW Storm Overflow River Usk 119 2,511h 49m -
Dwr Cymru Welsh Water Little Mill WwTW Overflow Berthin Brook 77 1,459h 45m -
Dwr Cymru Welsh Water Castell Coch Overflow Mill Reen 112 1,419h 37m -
Dwr Cymru Welsh Water Hunger Pill Overflow River Wye Estuary 99 1,387h 25m -
Dwr Cymru Welsh Water Goytre WwTW Storm Overflow River Usk 71 885h 22m -
Dwr Cymru Welsh Water Llangybi WwTW Storm Overflow River Usk 126 868h 15m -
Dwr Cymru Welsh Water Welsh Street Storm Overflow River Wye 100 795h 50m -
Dwr Cymru Welsh Water Forge Hammer Storm Overflow River Clydach 73 760h 30m -
Dwr Cymru Welsh Water Pandy WwTW Inlet Overflow. River Honddu 48 726h 15m -
Dwr Cymru Welsh Water Pentraeth WwTW Storm Overflow Afon Nodwydd 56 723h 30m -
Dwr Cymru Welsh Water Aberbaiden WwTW Inlet Storm Overflow River Usk 76 523h 25m -
Dwr Cymru Welsh Water Bryngwenin Overflow Mynachdy Brook 25 389h 44m -
Dwr Cymru Welsh Water Llanfoist WwTW Storm Overflow River Usk 54 383h 30m -
Dwr Cymru Welsh Water Caravan Park Clydach Storm Overflow River Clydach 42 370h -
Dwr Cymru Welsh Water Great Oak WwTW Storm Overflow Tributary of Clawdd Brook 29 361h 30m -
Dwr Cymru Welsh Water Tintern Main Road Storm Overflow River Wye 15 285h 40m -
Dwr Cymru Welsh Water Chepstow Fairfield Storm Overflow River Wye Estuary 66 281h 53m -
Dwr Cymru Welsh Water Wyesham Monmouth WwTW Storm Overflow River Wye 31 231h 30m -
Dwr Cymru Welsh Water Mill Street Castle Meadows Storm Overflow River Usk 50 194h 15m -
Dwr Cymru Welsh Water Mathern Storm Overflow Tributary of Mounton Brook 14 128h 25m -
Dwr Cymru Welsh Water Granville Street Riverbank Storm Overflow River Wye 27 95h 30m -
Dwr Cymru Welsh Water Little Mill Storm Overflow Berthin Brook 19 93h 30m -
Dwr Cymru Welsh Water Chepstow North Storm Overflow River Wye Estuary 43 55h 45m -
Dwr Cymru Welsh Water Thornwell Road Storm Overflow River Wye 36 53h 30m -
Dwr Cymru Welsh Water Mill Lane Usk Overflow River Usk 32 46h 40m -
Dwr Cymru Welsh Water Glangrwyney Road Storm Overflow River Clydach 16 33h 57m -
Dwr Cymru Welsh Water Tintern WwTW Overflow River Wye 22 22h 56m -
Dwr Cymru Welsh Water Unknown Unknown 3 18h 15m -
Dwr Cymru Welsh Water Blestium Street Monmouth Storm Overflow River Monnow 12 12h 45m -
Dwr Cymru Welsh Water Raglan WwTW Storm Overflow Nant Y Wilcae 9 10h 45m -
Dwr Cymru Welsh Water Raglan Way Storm Overflow River Wye 11 9h 14m -
Dwr Cymru Welsh Water Bluebell Drive Overflow River Wye 1 7h 30m -
Dwr Cymru Welsh Water West of Barton Bridge Storm Overflow Tributary of Nant Wilcae 5 5h 43m -
Dwr Cymru Welsh Water Cwrt Bryn Derwen Storm Overflow Olway Brook 1 2h 45m -
Dwr Cymru Welsh Water Magor Storm Overflow Severn Estuary 4 1h -
Dwr Cymru Welsh Water Unknown Unknown 0 0h -
Dwr Cymru Welsh Water North Hillcrest Road Monmouth Overflow River Wye 0 0h -
Dwr Cymru Welsh Water Caldicot Storm Overflow Severn Estuary 0 0h -
Dwr Cymru Welsh Water South Hillcrest Road Monmouth Overflow River Wye 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

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.

Top of the Poops

Analysing sewage pollution by the Water Industry

Follow on Instagram

Media Queries

Get in touch if you have queries or want to discuss our data.

press [at] top-of-the-poops.org

Please Support Us

We rely on donations to fund our work. Please support us if you can
Yes! Support TOTP!

© 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

Please don't scrape these pages - we can maybe share our data with you

Full Copyright information available at: our GitHub page