Thames Water

Responsible for at least 23,061 sewage overflows in 2024

On average 63.2 times a day

These lasted for 298,080 hours

That's 34.5 years!

Affecting 525 different locations across their service area

Map showing CSO locations for Thames Water

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Thames Water has 5 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 . ThW0001

Didcot and Wantage

Started 3 days ago

2 . ThW0079

Dorking and Horley

Started 5 days ago

3 . ThW0146

Harpenden and Berkhamsted

Started 2 days ago

4 . ThW0177

Banbury

Started 1 week ago

5 . ThW0282

Chelsea and Fulham

Started 2 weeks ago

How many Sewage Overflows are dumping sewage?

We have live data for Thames 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 Thames 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.

Thames Water is highlighted in the plot below

2024 - Worst Locations: Thames Water

1 . South Moreton

Didcot and Wantage

Mill Brook

5,353 hours - That's 7.43 months.

261 incidents - 5 times a week, on average

2 . WINTERBOURNE STW, WINTERBOURNE, BER

Newbury

Winterbournestream

5,062 hours - That's 7.03 months.

219 incidents - 4.2 times a week, on average

3 . Amersham Balancing Tanks

Chesham and Amersham

Misbourne

4,842 hours - That's 6.72 months.

210 incidents - 4 times a week, on average

4 . STEWKLEY WASTEWATER TREATMENT WORKS

Buckingham and Bletchley

Hardwick Brook

4,482 hours - That's 6.22 months.

217 incidents - 4.2 times a week, on average

5 . CIRENCESTER WWTW

South Cotswolds

Shorncote Ditch

4,459 hours - That's 6.19 months.

236 incidents - 4.5 times a week, on average

6 . BODDINGTON WWTW

Daventry

Boddington Canal Feeder

4,433 hours - That's 6.16 months.

235 incidents - 4.5 times a week, on average

2024 - Rivers Polluted by Thames Water

1 . River Cherwell

9,097 hours

- That's 1.05 years!

667 incidents - On average 1.8 times a day

2 . Misbourne

7,681 hours

- That's 10.67 months.

354 incidents - 6.8 times a week, on average

3 . River Thames

7,309 hours

- That's 10.15 months.

1,077 incidents - On average 3 times a day

4 . Hanwell Brook

6,148 hours

- That's 8.54 months.

422 incidents - On average 1.2 times a day

5 . Mill Brook

5,353 hours

- That's 7.43 months.

261 incidents - 5 times a week, on average

6 . Winterbournestream

5,062 hours

- That's 7.03 months.

219 incidents - 4.2 times a week, on average

2024 - Beaches Polluted by Thames Water

1 . Wolvercote Mill Stream

15,444 hours

- That's 1.79 years!

866 incidents - On average 2.4 times a day

2 . Wallingford Beach, River Thames

1,770 hours

- That's 2.46 months.

101 incidents - 1.9 times a week, on average

3 . Frensham Great Pond

9 hours

- That's 0.38 days.

6 incidents - 0.5 times a month, over the year

Water Companies

These water companies are responsible for managing sewage treatment and preventing pollution in our waterways.

Anglian Water

Dwr Cymru Welsh Water

Northumbrian Water

Scottish Water

Severn Trent Water

South West Water

Southern Water

Thames Water

United Utilities

Wessex Water

Yorkshire Water

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.

Analysing sewage pollution by the Water Industry

Media Queries

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

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

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