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Caerphilly - 2025 Sewage

Polluted by sewage 7,590 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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View Annual Sewage Data

You're looking at the totals that we have calculated for sewage in Caerphilly 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.

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Constituencies near Caerphilly

Daily Data

Jan - 0 hours
Feb - 568 hours
Mar - 16 hours
Apr - 158 hours
May - 39 hours
Jun - 81 hours
Jul - 13 hours
Aug - 32 hours
Sept - 593 hours
Oct - 426 hours
Nov - 2,111 hours
Dec - 3,548 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!
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Totals so far

Company Site Name Receiving Waterway Overflow Days Total Duration (hours) Offline/Potential Pollution
Dwr Cymru Welsh Water Bedwas Road Storm Overflow Porset Brook 99 1,081 h 3m -
Dwr Cymru Welsh Water Glan-yr-Afon Lane 2 Storm Overflow River Rhymney 92 1,064 h 26m -
Dwr Cymru Welsh Water Pontllanfraith Gelligroes Mill Road Storm Overflow Sirhowy River 93 917 h 59m -
Dwr Cymru Welsh Water Cwm Las Storm Overflow River Rhymni 72 805 h 22m -
Dwr Cymru Welsh Water Caerphilly Bypass Supermarket Storm Overflow Nant Yr Aber 38 476 h 14m -
Dwr Cymru Welsh Water Twyn Road Ystrad Mynach Storm Overflow River Rhymni 59 474 h 57m -
Dwr Cymru Welsh Water Springfield Estate Storm Overflow River Sirhowy 61 438 h 18m -
Dwr Cymru Welsh Water Bryn Siriol Storm Overflow Nant Yr Aber 43 384 h 30m -
Dwr Cymru Welsh Water A472 Maesycwmmer Storm Overflow River Rhymni 54 286 h 9m -
Dwr Cymru Welsh Water Oaks End Close Footbridge Storm Overflow Nant Cylla 65 237 h 41m -
Dwr Cymru Welsh Water River Terrace Pengham Storm Overflow River Rhymney 35 196 h 45m -
Dwr Cymru Welsh Water Ford Road Pengam Storm Overflow River Rhymni 47 179 h 15m -
Dwr Cymru Welsh Water Pentwyngwyn Road Storm Overflow River Rhymney 40 159 h 18m -
Dwr Cymru Welsh Water William Street Tir-y-berth Storm Overflow River Rhymney 42 150 h 33m -
Dwr Cymru Welsh Water South of Nine Mile Point Road Wattsville Storm Overflow Sirhowy River 25 111 h 1m -
Dwr Cymru Welsh Water Gelligroes Roundabout A472 Storm Overflow Sirhowy River 61 104 h 52m -
Dwr Cymru Welsh Water Trelyn Lane Storm Overflow River Rhymni 27 99 h 51m -
Dwr Cymru Welsh Water Pontllanfraith Tram Road Storm Overflow Sirhowy River 25 89 h 15m -
Dwr Cymru Welsh Water Ystrad Mynach Bridge Storm Overflow River Rhymney 23 76 h 45m -
Dwr Cymru Welsh Water Wyllie Halt Storm Overflow Sirhowy River 18 66 h 40m -
Dwr Cymru Welsh Water Pant Glas Industrial Estate Storm Overflow River Rhymney 15 57 h 15m -
Dwr Cymru Welsh Water Woodland Place Storm Overflow River Rhymney 23 38 h 56m -
Dwr Cymru Welsh Water High Street Gant-y-nant Storm Overflow River Rhymni 8 18 h 48m -
Dwr Cymru Welsh Water Nine Mile Point Storm Overflow River Sirhowy 8 17 h 8m -
Dwr Cymru Welsh Water Graig-Y-Fedw Storm Overflow Nant Yr Aber 7 15 h 19m -
Dwr Cymru Welsh Water Commercial Street Senghenydd Storm Overflow Nant Cwm-Parc 10 7 h 56m -
Dwr Cymru Welsh Water Coopers Court Storm Overflow River Rhymni 9 5 h 46m -
Dwr Cymru Welsh Water Windsor Place Storm Overflow Nant Yr Aber 5 5 h 43m -
Dwr Cymru Welsh Water Forge Road Machen Overflow River Rhymni 4 4 h 30m -
Dwr Cymru Welsh Water Senghenydd Storm Overflow Nant Yr Aber 3 4 h -
Dwr Cymru Welsh Water Glan-y-nant Riverside Path Storm Overflow River Rhymni 3 3 h 36m -
Dwr Cymru Welsh Water Forge Road Storm Overflow River Rhymni 6 3 h 10m -
Dwr Cymru Welsh Water Riverside Park Trethomas Storm Overflow River Rhymney 6 2 h 37m -
Dwr Cymru Welsh Water Islwyn Road Storm Overflow Sirhowy River 3 1 h 14m -
Dwr Cymru Welsh Water New Road Roundabout Storm Overflow River Rhymni 1 0 h 59m -
Dwr Cymru Welsh Water Nantgawr Road Storm Overflow Nant-yr-Aber 1 0 h 59m -
Dwr Cymru Welsh Water Trelyn Park Storm Overflow River Rhymney 2 0 h 41m -
Dwr Cymru Welsh Water Railway Cottages Storm Overflow Sirhowy River 1 0 h 28m -
Dwr Cymru Welsh Water Main Road Maesycwmmer Overflow Rhymney River 1 0 h 17m -
Dwr Cymru Welsh Water Coedcae Road Abertridwr Storm Overflow Nant Yr Aber 1 0 h 15m -
Dwr Cymru Welsh Water Victoria Road Fleur-De-Lis Storm Overflow River Rhymni 0 0 h -
Dwr Cymru Welsh Water Church Street Ystrad Mynach Overflow River Rhymni 0 0 h -
Dwr Cymru Welsh Water Church Street Rear Ystrad Mynnach Storm Overflow Nant Caeach 0 0 h -
Dwr Cymru Welsh Water William Street Fleur-de-lis Storm Overflow River Rhymney 0 0 h -
Dwr Cymru Welsh Water Greenway Bedwas Storm Overflow River Rhymni 0 0 h -

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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© 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

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