Overflow history upstream of River Ouse (Sussex), Barcombe Mills
The spot's forecast · For event organisers
This page lists the monitored storm overflows upstream of this spot and how often each spilled in each year. It is not a water test, and it does not say whether the water is fit to swim in. It does not include farm runoff, misconnected drains, treated sewage effluent, wildlife or overflows without a monitor. A year's count depends on how long the monitor worked, shown as monitor uptime.
Each year, all overflows upstream
| Year | Overflows with a return | Spills | Spill hours | Spill hours, weighted by reach |
|---|---|---|---|---|
| 2021 | 34 | 908 | 8,635 | 155 |
| 2022 | 43 | 1,118 | 12,362 | 297 |
| 2023 | 44 | 1,634 | 19,292 | 542 |
| 2024 | 45 | 1,842 | 21,172 | 508 |
| 2025 | 45 | 857 | 7,296 | 170 |
Reach is the share of a spill's bacteria SwimSignal's model expects to arrive here, after die-off on the way and dilution by the river. Weighting by it counts an hour of spilling just upstream for far more than one 40 km away. Spills are counted by the Environment Agency's 12/24 method: any discharge in the first 12 hours counts as one spill, then one more for each 24 hours with any discharge. How reach is worked out.
The overflows, by reach
All 47, the one whose spills matter most here first. Hours away is how long sewage takes to arrive at the model's river speed.
| Overflow and id | Company | km upstream | Hours away | Reach | Spills 2023 | Spills 2024 | Spills 2025 | Spill hours 2025 | Monitor uptime 2025 |
|---|---|---|---|---|---|---|---|---|---|
| Newick storm sewage overflow Newick SSO - 115728 · SWS00602 | Southern Water | 12.0 | 7 | 27% | 38 | 28 | 15 | 64 | 100% |
| Newick storm overflow Newick CSO - 115996 · SWS00601 | Southern Water | 12.0 | 7 | 27% | 30 | 28 | 18 | 36 | 100% |
| Scaynes Hill storm sewage overflow Scaynes Hill SSO - 115742 · SWS00746 | Southern Water | 20.7 | 12 | 14% | 61 | 58 | 32 | 291 | 100% |
| Scaynes Hill storm overflow Scaynes Hill CSO - 116199 · SWS00745 | Southern Water | 20.7 | 12 | 14% | 3 | 1 | 0 | 0 | 100% |
| Bell Lane Uckfield pumping station overflow Bell Lane Uckfield CEO - 108349 · SWS00054 | Southern Water | 11.3 | 6 | 10% | 4 | 4 | 3 | 14 | 100% |
| High Street Uckfield storm overflow High Street Uckfield CSO - 108371 · SWS00431 | Southern Water | 11.6 | 6 | 10% | 31 | 26 | 16 | 40 | 99% |
| Barcombe New storm sewage overflow Barcombe NEW SSO - 115373 · SWS00039 | Southern Water | 6.4 | 4 | 7% | 91 | 105 | 49 | 510 | 100% |
| Buxted storm sewage overflow Buxted SSO - 115400 · SWS00131 | Southern Water | 16.0 | 9 | 4% | 99 | 97 | 19 | 171 | 100% |
| Britts Farm Buxted pumping station overflow Britts Farm Buxted CEO - 110192 · SWS00100 | Southern Water | 15.2 | 8 | 2% | 0 | 0 | 0 | 0 | 100% |
| South Street Chailey pumping station overflow South Street Chailey CEO - 108337 · SWS00791 | Southern Water | 12.9 | 7 | 2% | 5 | 5 | 1 | 8 | 99% |
| Maresfield storm sewage overflow Maresfield SSO - 115778 · SWS00548 | Southern Water | 12.6 | 7 | 2% | 50 | 45 | 13 | 114 | 98% |
| Uckfield storm sewage overflow Uckfield SSO - 115857 · SWS00892 | Southern Water | 10.5 | 6 | 2% | 20 | 19 | 6 | 41 | 98% |
| Framfield Road Uckfield pumping station overflow Framfield Road Uckfield CEO - 108227 · SWS00331 | Southern Water | 12.6 | 7 | 2% | 8 | 2 | 1 | 1 | 100% |
| Blackboys storm sewage overflow Blackboys SSO - 115873 · SWS00069 | Southern Water | 18.5 | 10 | 1% | 81 | 103 | 48 | 397 | 99% |
| SWS90105 SWS90105 | Southern Water | 13.5 | 8 | 1% | – | – | – | – | – |
| Framfield Road Uckfield Outside storm overflow 29 Framfield Road Uckfield Outside 29 CSO - 108228 · SWS00238 | Southern Water | 12.7 | 7 | 1% | – | 0 | 0 | 0 | 100% |
| Framfield pumping station overflow Framfield CEO - 111797 · SWS00330 | Southern Water | 15.1 | 8 | 1% | 57 | 46 | 33 | 213 | 100% |
| Noahs Ark Lane Lindfield pumping station overflow Noahs ARK Lane Lindfield CEO - 108290 · SWS00606 | Southern Water | 24.6 | 14 | 1% | 15 | 3 | 2 | 12 | 100% |
| Lewes Road Lindfield pumping station overflow Lewes Road Lindfield CEO - 108273 · SWS00502 | Southern Water | 24.8 | 14 | 1% | 0 | 86 | 50 | 430 | 100% |
| Pelham Road Lindfield storm overflow Pelham Road Lindfield CSO - 108308 · SWS00698 | Southern Water | 25.8 | 14 | 1% | 68 | 96 | 50 | 287 | 100% |
| Haylind Road Haywards Heath storm overflow Haylind Road Haywards Heath CSO - 111829 · SWS00948 | Southern Water | 25.2 | 14 | 1% | 50 | 47 | 32 | 110 | 100% |
| Penn Crescent Haywards Heath Outside storm overflow 31 Penn Crescent Haywards Heath Outside 31 CSO - 108309 · SWS00920 | Southern Water | 25.7 | 14 | 1% | 38 | 28 | 13 | 23 | 100% |
| Western Road Haywards Heath storm overflow Western Road Haywards Heath CSO - 108811 · SWS00931 | Southern Water | 25.7 | 14 | 1% | 2 | 7 | 7 | 6 | 100% |
| Penn Crescent Haywards Heath Outside storm overflow 53 Penn Crescent Haywards Heath Outside 53 CSO - 108310 · SWS00653 | Southern Water | 25.7 | 14 | 1% | 1 | 1 | 5 | 11 | 85% |
| Horsted Keynes storm sewage overflow Horsted Keynes SSO - 115915 · SWS00452 | Southern Water | 28.1 | 16 | 1% | 85 | 99 | 11 | 78 | 100% |
| Jackies Lane Newick pumping station overflow Jackies Lane Newick CEO - 108263 · SWS00467 | Southern Water | 13.7 | 8 | 1% | 62 | 75 | 23 | 105 | 100% |
| Horsted Keynes pumping station overflow Horsted Keynes CEO - 115988 · SWS00451 | Southern Water | 28.1 | 16 | 1% | 0 | 0 | 0 | 0 | 100% |
| Strawlands Plumpton Green pumping station overflow Strawlands Plumpton Green CEO - 108350 · SWS00837 | Southern Water | 13.7 | 8 | 1% | 25 | 22 | 10 | 76 | 100% |
| Furnace Wood Fairwarp pumping station overflow Furnace Wood Fairwarp CEO - 109335 · SWS00299 | Southern Water | 17.0 | 9 | 1% | 23 | 64 | 10 | 53 | 100% |
| Coopers Green pumping station overflow Coopers Green CEO - 108210 · SWS00201 | Southern Water | 14.8 | 8 | 1% | 18 | 28 | 14 | 44 | 100% |
| Ditchling storm sewage overflow Ditchling SSO - 115798 · SWS00251 | Southern Water | 17.9 | 10 | 1% | 151 | 158 | 85 | 1,141 | 99% |
| Halland storm sewage overflow Halland SSO - 115932 · SWS00387 | Southern Water | 17.3 | 10 | 1% | 140 | 183 | 76 | 1,208 | 100% |
| Staplefield storm overflow Staplefield CSO - 116128 · SWS00823 | Southern Water | 34.7 | 19 | 1% | 33 | 30 | 19 | 125 | 100% |
| Wivelsfield pumping station overflow Wivelsfield CEO - 108387 · SWS00962 | Southern Water | 16.3 | 9 | 1% | 15 | 27 | 28 | 279 | 100% |
| Danehill storm sewage overflow Danehill SSO - 115720 · SWS00245 | Southern Water | 19.6 | 11 | 1% | 90 | 110 | 49 | 637 | 100% |
| Nursery Lane Nutley pumping station overflow Nursery Lane Nutley CEO - 108298 · SWS00624 | Southern Water | 18.6 | 10 | 1% | 11 | 14 | 23 | 57 | 100% |
| School Lane Danehill storm overflow School Lane Danehill CSO - 108311 · SWS00749 | Southern Water | 19.7 | 11 | 1% | 0 | 0 | 2 | 3 | 59% |
| SWS90018 SWS90018 | Southern Water | 31.8 | 18 | 1% | – | – | – | – | – |
| Portsmouth Lane Lindfield pumping station overflow Portsmouth Lane Lindfield CEO - 108316 · SWS00673 | Southern Water | 27.3 | 15 | 1% | 3 | 6 | 2 | 7 | 100% |
| Ardingly storm sewage overflow Ardingly SSO - 115774 · SWS00021 | Southern Water | 28.0 | 16 | 0% | 36 | 36 | 17 | 122 | 98% |
| Balcombe storm sewage overflow Balcombe SSO - 115796 · SWS00035 | Southern Water | 30.8 | 17 | 0% | 98 | 59 | 33 | 416 | 100% |
| Pasture Hill Road storm overflow Pasture Hill Road CSO - 111608 · SWS00646 | Southern Water | 27.8 | 16 | 0% | 20 | 25 | 10 | 51 | 100% |
| Balcombe pumping station overflow Balcombe CEO - 115977 · SWS00034 | Southern Water | 30.8 | 17 | 0% | 23 | 39 | 7 | 55 | 94% |
| Mill Green Road Haywards Heath storm overflow Mill Green Road Haywards Heath CSO - 108287 · SWS00569 | Southern Water | 27.1 | 15 | 0% | 8 | 9 | 2 | 1 | 100% |
| Ardingly storm overflow Ardingly CSO - 111045 · SWS00022 | Southern Water | 28.0 | 16 | 0% | 3 | 4 | 3 | 6 | 98% |
| St James Cottage Balcombe storm overflow ST James Cottage Balcombe CSO - 108896 · SWS00812 | Southern Water | 32.5 | 18 | <1% | 14 | 16 | 10 | 25 | 88% |
| West Hoathly pumping station overflow West Hoathly CEO - 108378 · SWS00922 | Southern Water | 32.0 | 18 | <1% | 24 | 3 | 10 | 28 | 99% |
A dash: no annual return for that overflow in that year.
Sources and credits
Storm overflow annual returns: © Environment Agency copyright and/or database right 2025, Open Government Licence v3.0. Overflow positions: the water companies via the National Storm Overflow Hub, CC BY 4.0. River network: contains OS data © Crown copyright and database right 2026 (OS Open Rivers). Traced and weighted by SwimSignal (swimsignal.co.uk), whose method is at swimsignal.co.uk/methods.html. All credits and licences.