Polluted by sewage 6,859 hours in 2026 , monitoring offline 429 hours so far..
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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Donate Now| Company | Site Name | Receiving Waterway | Overflow Days | Total Duration (hours) | Offline/Potential Pollution |
|---|---|---|---|---|---|
| Thames Water | Hanwell STW | Hanwell Brook | 53 | 1,151h | - |
| Thames Water | Cropredy STW | River Cherwell | 59 | 1,117h 30m | - |
| Thames Water | Chadlington STW | Chadlington Stream | 48 | 876h | - |
| Thames Water | Bloxham STW | Bloxham Brook | 52 | 786h 30m | 359 h |
| Thames Water | Wardington SPS | River Cherwell | 63 | 676h 45m | - |
| Thames Water | Banbury STW | River Cherwell | 36 | 545h | - |
| Thames Water | Chipping Norton STW | Blue Brook | 29 | 503h 15m | - |
| Thames Water | Shutford STW | Shutford Stream | 30 | 317h 15m | - |
| Thames Water | Hook Norton STW | Hook Nortonbrook | 16 | 186h 15m | - |
| Thames Water | Horley (Oxon) STW | Sor Brook | 24 | 186h 15m | - |
| Thames Water | Middle Barton STW | River Dorn | 28 | 136h 45m | - |
| Thames Water | The Mill (Kingham) SPS | Cornwell Brook | 20 | 113h 30m | - |
| Thames Water | Finstock STW | River Evenlode | 11 | 84h 30m | - |
| Thames Water | Clifton STW | Clifton Brook | 11 | 68h | - |
| Anglian Water | FRITWELL STW | Padbury Brook River Great Ouse | 13 | 48h 18m | - |
| Thames Water | Charlbury STW | Evenlode | 8 | 47h 15m | - |
| Thames Water | Hornton STW | Hornton Stream | 1 | 15h | 70 h |
| Thames Water | Finstock STW | River Evenlode | 0 | 0h | - |
| Thames Water | Cherwell Street (Banbury) SPS & SSP | River Cherwell | 0 | 0h | - |
| Thames Water | Bloxham STW | Bloxham Brook | 0 | 0h | - |
| Thames Water | Chipping Norton STW | Blue Brook | 0 | 0h | - |
| Thames Water | Clifton STW | Clifton Brook | 0 | 0h | - |
| Thames Water | The Mill (Kingham) SPS | Cornwell Brook | 0 | 0h | - |
| Thames Water | Banbury STW | River Cherwell | 0 | 0h | - |
| Thames Water | Fergusson road, banbury | Cherwell | 0 | 0h | - |
| Thames Water | Chadlington STW | Chadlington Stream | 0 | 0h | - |
| Thames Water | Hanwell STW | Hanwell Brook | 0 | 0h | - |
| Thames Water | Charlbury STW | Evenlode | 0 | 0h | - |
| Thames Water | Cherwell Street (Banbury) SPS & SSP | River Cherwell | 0 | 0h | - |
| Thames Water | Hornton STW | Hornton Stream | 0 | 0h | - |
| Thames Water | Middle Barton STW | River Dorn | 0 | 0h | - |
| Thames Water | Hook Norton STW | Hook Nortonbrook | 0 | 0h | - |
| Thames Water | Wardington SPS | River Cherwell | 0 | 0h | - |
| Thames Water | Shutford STW | Shutford Stream | 0 | 0h | - |
| Thames Water | Cropredy STW | River Cherwell | 0 | 0h | - |
| Thames Water | Horley (Oxon) STW | Sor Brook | 0 | 0h | - |
| Anglian Water | FRITWELL STW | Padbury Brook River Great Ouse | 0 | 0h | - |
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
Annual figures up to and including 2025 come from official water company returns. The 2026 figure is our own estimate, derived continuously from the companies' live data feeds.
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.