Wessex Water

was responsible for at least 41,453 sewage overflows in 2023
On average 113.6 times a day

These lasted for 372,340 hours (That's 43.09 years!) - in 1,118 different locations across their service area

2023 - 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.

2023 - 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.

Wessex Water is highlighted in the plot below

2023 - Worst Locations Wessex Water

1. SHREWTON WATER RECYCLING CENTRE

East Wiltshire polluted for 6,183 hours, into River Till

262 incidents

That's 8.59 months.

5 times a week, on average

2. SPANIEL'S BRIDGE PUMPING STATION

Melksham and Devizes polluted for 4,210 hours, into River Avon

193 incidents

That's 5.85 months.

3.7 times a week, on average

3. HURDCOTT WASTEWATER TREATMENT WORKS

Salisbury polluted for 3,980 hours, into River Bourne

253 incidents

That's 5.53 months.

4.9 times a week, on average

4. WOOKEY WATER RECYCLING CENTRE

Wells and Mendip Hills polluted for 3,696 hours, into River Axe

217 incidents

That's 5.13 months.

4.2 times a week, on average

5. CHICKSBRIDGE PS

West Dorset polluted for 3,671 hours, into River Bride

184 incidents

That's 5.1 months.

3.5 times a week, on average

6. GREAT BADMINTON WWTW

Thornbury and Yate polluted for 3,654 hours, into Luckington Brook

167 incidents

That's 5.08 months.

3.2 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, and Scottish Water

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.