Dwr Cymru Welsh Water

was responsible for 81,937 sewage overflows in 2022
On average 224.5 times a day

These lasted for 573,201 hours (That's 66.34 years!) - in 1,831 different locations across their service area

Worst Locations Dwr Cymru Welsh Water

1. STATION ROW CSO PONTYRHYL BRIDGEND

Ogmore polluted for 7,804 hours, into River Garw

340 incidents

That's 10.84 months.

6.5 times a week, on average

2. BETTWS ROAD CSO LLANGEINOR

Ogmore polluted for 7,784 hours, into River Garw

350 incidents

That's 10.81 months.

6.7 times a week, on average

3. Abererch WwTW Storm Overflow

Dwyfor Meirionnydd polluted for 4,298 hours, into River Erch

224 incidents

That's 5.97 months.

4.3 times a week, on average

4. CWRT NEWYDD STW STORM OVERFLOW

Ceredigion polluted for 4,280 hours, into Nant Cledlyn

366 incidents

That's 5.94 months.

On average 1 times a day

5. Settled Storm Overflow at Carmel Wastewater Treatment Works

Carmarthen East and Dinefwr polluted for 3,900 hours, into River Marlas

226 incidents

That's 5.42 months.

4.3 times a week, on average

6. CSO at Llanbrynmair STW Llanbrynmair

Montgomeryshire polluted for 3,663 hours, into River Laen

261 incidents

That's 5.09 months.

5 times a week, on average

Water Companies

Data Sources & Accuracy

EDM (Event Duration Monitoring) data and Consented Discharges to Controlled Waters with Conditions from Environment Agency & Data Map Wales

Experimental derived data from Thames Water API, Some data may be missing or inaccurate. This 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.