Storm overflow register · 2025 annual return

United Utilities storm overflows, 2025

United Utilities reported 2,270 storm overflows in England for 2025. Together they recorded 60,843 spills over 327,452 hours, an average of 26.8 spills per overflow against 20.4 across England. That ranks 9 of 10 companies, where 1 is the fewest spills per overflow. Counting the same overflows in both years, spills were down 23% on 2024.

295 overflows did not spill · 313 spilled more than 60 times · 2,076 had monitors working for 90% of the year or more · 289 sewage treatment works with overflows

Hours spilling by month, 2025

Hours spilling, all United Utilities overflows, from the start/stop records. Spills running across a month end are split between the months.

All United Utilities storm overflows

Sorted by hours spilling. Open an overflow for its permit, location, reasons for high spills and improvement status.

Overflow	Discharges to	Spills vs 2024	Monitor uptime
Entwistle St CSO Overflow on sewer network Company site name Entwistle Street Combined Sewer Overflow (073DQ) (BOL0093) EA ID / permit UUP00706 · 016983217 Outlet location SD7269009850 (OS grid reference) · View on Apple Maps WFD catchment Tonge (GB112069064530) 2024 spills / hours 0 / 0.0 Long-term average 24.6 spills a year (monitored since 2019) Monitor below 90% Telemetry or data archiving failure / issue · Resolved - Nov Investigation No investigation activity in reporting period Improvement No improvement action in reporting period	River Tonge	no change	76%
Motherby Wastewater Treatment Works Inlet overflow at sewage works Sewage works Motherby Company site name MOTHERBY WwTW EA ID / permit UUP01356 · 017670105 Outlet location NY4322028690 (OS grid reference) · View on Apple Maps WFD catchment Petteril u/s M6 (GB102076073992) 2024 spills / hours 55 / 76 Long-term average 27.5 spills a year (monitored since 2024) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period	River Petteril	down 100%	100%
Ainslie St Oxford St CSO 041A9 Overflow on sewer network Company site name Ainslie Street/Oxford Street CSO EA ID / permit UUP00089 · 017480392 Outlet location SD1966070550 (OS grid reference) · View on Apple Maps WFD catchment Furness Permo-Triassic sandstone aquifers (GB41201G101900) Bathing water Walney West Shore Shellfish water Walney 2024 spills / hours 11 / 1.5 Long-term average 28.8 spills a year (monitored since 2017) Investigation No investigation activity in reporting period Improvement Env Act (SODRP) improvement ongoing	Ormsgill Reservoir	down 100%	98%
Failsworth WwTW Storm tank at sewage works Sewage works Failsworth Company site name FAILSWORTH WwTW EA ID / permit UUP00713 · 016983268 Outlet location SJ8960099710 (OS grid reference) · View on Apple Maps WFD catchment Medlock (Lumb Brook to Irwell) (GB112069061152) 2024 spills / hours 1 / 1.7 Long-term average 29.0 spills a year (monitored since 2021) Investigation Operational investigation completed Improvement Operational improvement completed	The River Medlock	down 100%	99%
Riverside CSO Bolto BOL0058 Overflow on sewer network Company site name Riverside CSO EA ID / permit UUP01662 · 016950464 Outlet location SD7633005220 (OS grid reference) · View on Apple Maps WFD catchment Irwell (Croal to Irk) (GB112069061451) 2024 spills / hours 0 / 0.0 Long-term average 29.4 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period	River Irwell	no change	100%
Stonegarth Combined Sewer Overflow Overflow on sewer network Company site name STONEGARTH CSO EA ID / permit UUP01870 · 01CAR0012 Outlet location NY3821054740 (OS grid reference) · View on Apple Maps WFD catchment Caldew d/s Caldbeck (GB102076073880) 2024 spills / hours 16 / 18 Long-term average 29.8 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period	Dow Beck Culvert	down 100%	93%
Kenyon Lane CSO Overflow on sewer network Company site name Kenyon Lane CSO EA ID / permit UUP01057 · 016982953 Outlet location SD8770001160 (OS grid reference) · View on Apple Maps WFD catchment Irk (Wince to Irwell) (GB112069061131) 2024 spills / hours 33 / 132 Long-term average 39.0 spills a year (monitored since 2020) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period	Trib River Irk	down 100%	100%
Lancaster Road/Hayfield Road Tank Overflow on sewer network Company site name Lancaster Road/Hayfield Road Detention Tank EA ID / permit UUP01101 · 016993482 Outlet location SJ7877099770 (OS grid reference) · View on Apple Maps WFD catchment Irwell / Manchester Ship Canal (Irk to confluence with Upper Mersey) (GB112069061452) 2024 spills / hours 54 / 7.4 Long-term average 39.0 spills a year (monitored since 2020) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period	Gilda Brook(Manc Ship) via SWS	down 100%	100%
Blackpool Old Road CSO Overflow on sewer network Company site name Blackpool Old Road CSO EA ID / permit UUP00253 · 017290529 Outlet location SD3372038940 (OS grid reference) · View on Apple Maps WFD catchment WYRE - transitional (GB531207212200) Bathing water St Annes; St Annes North 2024 spills / hours 15 / 13 Long-term average 45.1 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period	Horsebridge Dyke (trib of Main Dyke)	down 100%	100%
Marsh Lane CSO PRE0021 Overflow on sewer network Company site name Marsh Lane CSO EA ID / permit UUP01257 · 017190874 Outlet location SD5269129413 (OS grid reference) · View on Apple Maps WFD catchment RIBBLE_Transitional (GB531207112400) Bathing water St Annes 2024 spills / hours 137 / 302 Long-term average 45.7 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period	Chain Caul culvert, via a surface water sewer	down 100%	100%
Staveley WwTW Inlet overflow at sewage works Sewage works Staveley Company site name STAVELEY WwTW EA ID / permit UUP01855 · 017370061 Outlet location SD4827098020 (OS grid reference) · View on Apple Maps WFD catchment Kent - conf Gowan to conf Sprint (GB112073071380) 2024 spills / hours 1 / 0.2 Long-term average 47.3 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing, Operational investigation completed Improvement Env Act (SODRP) improvement ongoing, Operational improvement completed	River Kent	down 100%	100%
Birkenhead WwTW Birke Inlet overflow at sewage works Sewage works Birkenhead Birke Company site name BIRKENHEAD WWTW EA ID / permit UUP00244 · 016993399 Outlet location SJ3292089440 (OS grid reference) · View on Apple Maps WFD catchment The Birket including Arrowe Brook and Fender (GB112068060530) Bathing water Moreton; Wallasey 2024 spills / hours 0 / 0.0 Long-term average 51.9 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period	River Birket (Great Culvert -downstream length) / Mersey Estuary	no change	100%
Wood Lane Road, near High Barn Cottage Lb Overflow on sewer network (with treatment) Company site name Park Hall Road combined sewer overflow (CHR0012a) EA ID / permit UUP02280 · Unpermitted Outlet location SD5330915616 (OS grid reference) · View on Apple Maps WFD catchment Syd Brook (GB112070064920) Treatment Reed bed 2024 spills / hours 117 / 663 Long-term average 58.5 spills a year (monitored since 2024) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period	Syd Brook	down 100%	100%
Askam-in-Furness WwTW Askam Inlet overflow at sewage works Sewage works Askam In Furness Askam Company site name ASKAM-IN-FURNESS WwTW EA ID / permit UUP00150 · 017470136 Outlet location SD2118078600 (OS grid reference) · View on Apple Maps WFD catchment Duddon Sands (GB641211172000) Bathing water Haverigg; Walney Biggar Bank; Walney West Shore; Walney Sandy Gap Shellfish water Duddon; Walney 2024 spills / hours 1 / 0.0 Long-term average 61.0 spills a year (monitored since 2018) Investigation Operational investigation ongoing Improvement Operational improvement ongoing	Blea Beck	down 100%	100%
Lawton Road Wesley Ave CSO 132CM Overflow on sewer network Company site name Lawton Road/Wesley Avenue CSO EA ID / permit UUP01122 · 016892429 Outlet location SJ7989056282 (OS grid reference) · View on Apple Maps WFD catchment Kidsgrove Stream (including Day Green Stream) (GB112068055390) 2024 spills / hours 106 / 1,092 Long-term average 67.3 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period	Cresswellshawe Brook via SWS	down 100%	99%
Strangeway No.1 Ww Ntwk PS Storm discharge at pumping station Company site name Strangeways No1 Ww Ntwk PS EA ID / permit UUP01880 · 01WIG0097 Outlet location SD6132003450 (OS grid reference) · View on Apple Maps WFD catchment Hey/Borsdane Brook (GB112069064520) 2024 spills / hours 141 / 3,226 Long-term average 70.5 spills a year (monitored since 2024) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period	Borsdane Brook	down 100%	100%
Lindal Pumping Station 04509 Storm discharge at pumping station Company site name Lindal PS EA ID / permit UUP01146 · 017370050 Outlet location SD2471075510 (OS grid reference) · View on Apple Maps WFD catchment Deep Meadows Beck (GB112073071150) Bathing water Haverigg Shellfish water Walney 2024 spills / hours 39 / 100 Long-term average 71.4 spills a year (monitored since 2017) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period	Tributary of Clarkes Beck	down 100%	100%
Newbiggin (Leven) WwTW Newbg Storm tank at sewage works Sewage works Newbiggin Newbg Company site name NEWBIGGIN WwTW EA ID / permit UUP01381 · 017370051 Outlet location SD2675168941 (OS grid reference) · View on Apple Maps WFD catchment Deep Meadows Beck (GB112073071150) 2024 spills / hours 205 / 3,863 Long-term average 101.0 spills a year (monitored since 2018) Monitor below 90% Telemetry or data archiving failure / issue · Resolved - Aug Investigation Operational investigation completed Improvement Operational improvement completed	Deep Meadows Beck	down 100%	58%
Longsight Park CSO 07038 Overflow on sewer network Company site name Longsight Park CSO EA ID / permit UUP00165 · 016982587 Outlet location SD7340211800 (OS grid reference) · View on Apple Maps WFD catchment Bradshaw Brook (GB112069064580) 2024 spills / hours 117 / 227 Long-term average 113.4 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period	Bradshaw Brook	down 100%	98%
Cargo Wastewater Treatment Works Inlet overflow at sewage works Sewage works Cargo Company site name CARGO WwTW EA ID / permit UUP00401 · 017670194 Outlet location NY3610058800 (OS grid reference) · View on Apple Maps WFD catchment Eden - Eamont to tidal (GB102076073940) 2024 spills / hours 2 / 22 Long-term average 205.0 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement Env Act (SODRP) improvement ongoing	River Eden	down 100%	94%

Sewage treatment works

Storm tanks and inlet overflows at each United Utilities sewage works. The figures are 2025 spills.

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