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Polluted by sewage 643 times in 2024 lasting 7,704 hours
Monitoring fell below 50% in some locations so could be more
So far this year (as of May 12, 2025, 1:15 PM) there has been 1,813 hours of sewage overflows
Your local MP is Chris Coghlan (Liberal Democrat) - Find out more about their interests, donors, and voting at They Work For You
We get information about overflowing CSOs since January 2025. Here is a chart of the last three months of data for Dorking and Horley, here you can see overflows in red, the darker the red, the more the CSO overflowed that day.
Each CSO has a row, the most recent data is on the right hand side.
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Donate NowHere are all the reported sewage overflow totals for Dorking and Horley in 2024. Sometimes sewage can be being dumped for months at a time.
Reporting refers to how much of the time the monitoring was active. In this constituency 1 of the total 19 CSO locations had reporting enabled for less than half the year.
| Company | Waterway | Site | Sewage Dumps | Duration (Hours) | Reporting % |
|---|---|---|---|---|---|
| Thames Water | Burstow Stream | BURSTOW STW, HATHERSHAM ROAD, SMALL | 133 | 1,758 | 99.6 |
| Thames Water | Holmwood Stm Leigh Brk | HOLMWOOD SEWAGE TREATMENT WORKS | 107 | 1,630 | 99.9 |
| Thames Water | Mole | LEE STREET | 91 | 1,444 | 99.7 |
| Thames Water | River Mole | DORKING STW (STORM) | 69 | 978 | 99.5 |
| Thames Water | River Mole | IRONSBOTTOM (SIDLOW) WWTW | 63 | 858 | 86.2 |
| Thames Water | Mans Brook | CHARLWOOD, SURREY | 35 | 268 | 98.5 |
| Thames Water | River Mole | Brockham Bridge | 15 | 122 | 99.9 |
| Thames Water | Thornhurst Brook | Canfold Wood | 26 | 122 | 99.9 |
| Thames Water | River Mole | COACH ROAD CSO ON STONEBRIDGE SEWER | 11 | 121 | 36.3 |
| Thames Water | Mole | CASTLE GARDENS SPS | 12 | 119 | 100 |
| Thames Water | Deanoak Brook | CSO AT CAPEL SPS | 22 | 89 | 99.4 |
| Thames Water | Into Land | Box Hill | 9 | 46 | 90.6 |
| Thames Water | Bookham Brook | Commonside | 13 | 37 | 99.8 |
| Thames Water | Tanners Brook | SPOOKS HILL, NORTH HOLMWOOD, SURREY | 12 | 36 | 99.9 |
| Thames Water | Salfords Stream | SALFORDS SEWAGE PUMPING STATION | 8 | 35 | 99.9 |
| Thames Water | Cobbler'S Brook | Ockley Road | 7 | 17 | 100 |
| Thames Water | Mole | RIVER LANE PUMPING STATION, FETCHAM | 6 | 10 | 99.5 |
| Thames Water | Tanners Brook | SURFACE WATER SEWER | 4 | 8 | 100 |
| Thames Water | Deanoak Brook | Dean Oak Lane | 0 | 0 | 100 |
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.
Get in touch if you have queries or want to discuss our data.
press [at] top-of-the-poops.org