Dwr Cymru Welsh Water

Responsible for at least 105,986 sewage overflows in 2024

On average 290.4 times a day

These lasted for 856,351 hours

That's 99.11 years!

Affecting 2,025 different locations across their service area

Map showing CSO locations for Dwr Cymru Welsh Water
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Dwr Cymru Welsh Water has 250 CSOs dumping sewage right now

Here are the ones that have been overflowing for the longest, without interruption

We are getting more data collated for each of the CSOs... right now we just have the Constituency. Unfortunately, the water companies use different names for the CSOs in their live data than in the annual returns, so it will take a bit of time to link all the data up....

1 . 743016016d87b3394be6c77168d80c3299c57166c54ea507201d01930ddf122a
Started 3 months ago
2 . 6449fbc8b537e806b80fd4be2d7a270bfc650ec9daf83d8c6d7c5d59e905f1ca
Started 3 months ago
3 . 7947151681b2c2377bfc49edf323fb0fbb520b8f7e253b93eb00fa3b38479f26
Started 1 month ago
4 . 30ae2ae58a3e8d8617340e97e2cfce8370e46e1e02d1b6bce8cdceb42f453ae8
Started 1 month ago
5 . dab14caa93ecb424a3ca04113f5ac272051a23d8ab80c7f5ab35bcb5c8df02dd
Started 1 month ago
6 . 4fab3e03c6ae73fe9570ad7c0bbf18b7ae49dc1bf9b3d98165aef812bf07f061
Started 1 month ago
7 . a3ef6b9a8888e185683572e253997decb47904e7fc7f66095b4075b0834777c3
Started 1 month ago
8 . eb46c9df01567d20a2845bec07b40bc4c36fef9f5fc9dcd652a9ddf2a8963bd8
Started 1 month ago
9 . 50df999f38d046f7efea16fe614bd5476292062765d31595293d7fbc9ee7e337
Started 1 month ago

How many Sewage Overflows are dumping sewage?

We have live data for Dwr Cymru Welsh Water so we can track what happens every day - given that overflows are supposed to happen on an 'exceptional' basis only - does the chart indicate that?

Total CSOs monitored
CSOs overflowing (30+ mins)
CSOs offline (30+ mins)

There is daily updated information on all constituencies covered by Dwr Cymru Welsh Water

2024 - By Water Company

How does each water company compare? These are the totals by company for each. The totals are really high, counting things in hours doesn't make it very easy to think about. Here we show how many years of continuous sewage dumps happened in a single year, by water company.

2024 - Asset Spill Duration Comparison

It isn't like there are just a few outliers... the problem exists across the entire estate of water assets. Here we show a 'cumulative frequency diagram' - where the number of CSOs that dumped sewage for a time, or longer, is shown. You can see that many CSOs dumped sewage into a river for months and months.

Dwr Cymru Welsh Water is highlighted in the plot below

2024 - Worst Locations: Dwr Cymru Welsh Water

1 . Pwllmeyric SPS (CSO)
6,266 hours - That's 8.7 months.
278 incidents - 5.3 times a week, on average
2 . Reynoldson WwTW Settled Storm
5,302 hours - That's 7.36 months.
253 incidents - 4.9 times a week, on average
3 . CRYNANT STW CRYNANT NEATH
5,190 hours - That's 7.21 months.
258 incidents - 5 times a week, on average
4 . CSO 6 NR BRYN MARLAIS FARM
4,812 hours - That's 6.68 months.
256 incidents - 4.9 times a week, on average
5 . Ewenni No 2 Pumping Station
4,778 hours - That's 6.64 months.
211 incidents - 4.1 times a week, on average
6 . Commins Coch Pumping Station CSO
4,270 hours - That's 5.93 months.
190 incidents - 3.7 times a week, on average

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.