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Polluted by sewage 199 times in 2025 - lasting 1,467 hours
Portsmouth Harbour was the #19 most polluted shellfish area in England & Wales, by duration of sewage overflows, as reported by the water companies
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Donate NowHere are all the reported sewage overflow totals for Portsmouth Harbour in 2025.
We use data from the water companies, but we are seeing many anomalies that make us believe that location information is quite poor. The situation is likely far worse than reported here.
In particular: Totals on this page can differ from totals in the Ranked Shellfish page - number on this page are higher - this is due to a lack of standardization on shellfish area names. This page more accurately counts the differing names. For example "Solway" and "SOLWAY" are counted as different in the rankings, but correctly aggregated here.
Other CSO Combined Sewage Overflow - a device that, when operating, pours combined rainwater & sewage into a waterway s may also be located nearby, however the water companies claim that these do not affect the water quality here.
| Company | Waterway | Site | Sewage Dumps | Duration (Hours) | Reporting % |
|---|---|---|---|---|---|
| Southern Water | River Meon | WICKHAM WWTW | 59 | 1,040 | 99.4 |
| Southern Water | River Wallington | SOUTHWICK WWTW | 9 | 93 | 99.5 |
| Southern Water | Hoeford Lake | HOEFORD FAREHAM CEO | 16 | 61 | 99.7 |
| Southern Water | Fareham Lake | FAREHAM ROAD GOSPORT OUTSIDE 359CSO | 26 | 46 | 99.7 |
| Southern Water | Black Brook | ELMHURST ROAD (COMPASS POINT) CSO | 19 | 37 | 99.6 |
| Southern Water | Blackbrook Stream | THE GILLIES FAREHAM CSO | 11 | 32 | 99.7 |
| Southern Water | Wallington River | HIGH STREET FAREHAM CSO | 12 | 29 | 100 |
| Southern Water | Fareham Creek/Portsmouth Hbr | QUAY STREET, FAREHAM CSO | 5 | 28 | 99.7 |
| Southern Water | Saline Estuary | GREEN CRESCENT O/FLOW | 2 | 19 | 85.9 |
| Southern Water | Black Brook | ARUNDEL DRIVE FAREHAM CSO | 14 | 18 | 99.7 |
| Southern Water | River Wallington | NEWMANS BRIDGE SOUTHWICK CEO | 3 | 17 | 99.9 |
| Southern Water | Frater Lake, Portsmouth Hbr | BREWERS LANE GOSPORT CSO | 2 | 13 | 99.7 |
| Southern Water | Black Brook | REDLANDS LANE FAREHAM CSO | 5 | 12 | 99.7 |
| Southern Water | Frater Lake | FAREHAM ROAD GOSPORT O/S 68 CSO | 3 | 11 | 99.7 |
| Southern Water | Portsmouth Harbour | SALTERNS LANE FAREHAM CEO | 4 | 2 | 100 |
| Southern Water | Portsmouth Harbour | WICOR MILL LANE PORTCHESTER CEO | 5 | 1 | 100 |
| Southern Water | Portsmouth Harbour | COW LANE PORTCHESTER CEO | 1 | 0 | 100 |
| Southern Water | River Wallington | WICKHAM ROAD FAREHAM CSO | 2 | 0 | 99.5 |
| Southern Water | Portsmouth Harbour | SALTERNS LANE FAREHAM O/S 12 CSO | 1 | 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. Live sewage data from Stream Water API
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