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 2025	Hours 2025	Spills vs 2024	Monitor uptime
Oakcliffe Road CSO Overflow on sewer network Company site name Oakcliffe Road CSO EA ID / permit UUP01429 · 016993527 Outlet location SD9159014540 (OS grid reference) · View on Apple Maps WFD catchment Beal (GB112069064690) 2024 spills / hours 26 / 33 Long-term average 39.7 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 52 hours spilling →	Culverted Trib of River Roch	26	52	no change	100%
Greenleach Lane CSO Overflow on sewer network Company site name Greenleach Lane CSO EA ID / permit UUP00854 · 016993659 Outlet location SD7520001310 (OS grid reference) · View on Apple Maps WFD catchment Folly Brook and Salteye Brook (GB112069061430) 2024 spills / hours 10 / 35 Long-term average 12.0 spills a year (monitored since 2020) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 52 hours spilling →	Kempnough Brook	8	52	down 20%	100%
Eastham Rake CSO Overflow on sewer network Company site name Eastham Rake Combined Sewer Overflow (Site ID 51068) (WIR0111) EA ID / permit UUP00677 · 016892412 Outlet location SJ3483079350 (OS grid reference) · View on Apple Maps WFD catchment Dibbinsdale Brook and Clatter Brook (GB112068060270) 2024 spills / hours 25 / 78 Long-term average 18.3 spills a year (monitored since 2020) Investigation Env Act (SODRP) investigation ongoing Improvement Env Act (SODRP) improvement ongoing Volume & pollution Estimate from 52 hours spilling →	Dibbinsdale Brook	9	52	down 64%	100%
Yorkshire St Oswald St CSO 35024 Overflow on sewer network Company site name Yorkshire Street / Oswald Street CSO EA ID / permit UUP02187 · 016993538 Outlet location SD9044014030 (OS grid reference) · View on Apple Maps WFD catchment Roch (Source to Spodden) (GB112069064720) 2024 spills / hours 26 / 37 Long-term average 43.3 spills a year (monitored since 2019) High-spill reason (company) Not asset maintenance - Hydraulic capacity Investigation No investigation activity in reporting period Improvement Env Act (SODRP) improvement ongoing Volume & pollution Estimate from 51 hours spilling →	Hey Brook Trib of River Roch	31	51	up 19%	99%
Hesketh Bank WwTW Hskbk Storm tank at sewage works Sewage works Hesketh Bank Hskbk Company site name HESKETH BANK WwTW EA ID / permit UUP00943 · 017030023 Outlet location SD4562023980 (OS grid reference) · View on Apple Maps WFD catchment RIBBLE (GB531207112400) Bathing water Southport; St Annes; St. Annes North; Blackpool South 2024 spills / hours 22 / 131 Long-term average 14.6 spills a year (monitored since 2017) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 51 hours spilling →	Douglas Estuary	6	51	down 73%	100%
Westleigh Etherstone Md CSO 508AP Overflow on sewer network Company site name Westleigh/Etherstone Main Drainage CSO EA ID / permit UUP02088 · 016993705 Outlet location SJ6475099780 (OS grid reference) · View on Apple Maps WFD catchment Westleigh Brook (GB112069060820) 2024 spills / hours 16 / 51 Long-term average 11.0 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 51 hours spilling →	Westleigh Brook	13	51	down 19%	92%
Newearth Road CSO Overflow on sewer network Company site name Newearth Road CSO EA ID / permit UUP01393 · 01SAL0061 Outlet location SD7267001650 (OS grid reference) · View on Apple Maps WFD catchment Shaw Brook (GB112069061090) 2024 spills / hours 29 / 52 Long-term average 28.2 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 51 hours spilling →	Tributary of Ellen Brook	26	51	down 10%	100%
Stonehill Road CSO 07049 Overflow on sewer network Company site name Stonehill Road CSO EA ID / permit UUP01872 · 016982823 Outlet location SD7382704740 (OS grid reference) · View on Apple Maps WFD catchment Irwell (Croal to Irk) (GB112069061451) 2024 spills / hours 31 / 60 Long-term average 37.4 spills a year (monitored since 2019) Monitor below 90% Sensor failure / issue · Resolved - January after reporting year Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 51 hours spilling →	Singing Clough Brook	19	51	down 39%	77%
Duddle Lane CSO Overflow on sewer network Company site name Duddle Lane CSO EA ID / permit UUP00658 · 017180617 Outlet location SD5599026920 (OS grid reference) · View on Apple Maps WFD catchment Darwen - conf Roddlesworth to tidal (GB112071065300) 2024 spills / hours 12 / 73 Long-term average 7.2 spills a year (monitored since 2021) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 51 hours spilling →	Hennel Brook	8	51	down 33%	100%
Rear Meadow Lane CSO Overflow on sewer network Company site name Rear of XX Meadow Lane CSO EA ID / permit UUP01622 · 01VRY0106 Outlet location SJ6611069210 (OS grid reference) · View on Apple Maps WFD catchment Dane (Wheelock to Weaver) (GB112068060470) 2024 spills / hours 4 / 2.4 Long-term average 8.0 spills a year (monitored since 2021) High-spill reason (company) Not asset maintenance - Hydraulic capacity Monitor below 90% Sensor failure / issue · Resolved - Jul Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 51 hours spilling →	Trib Peckmill Brook via SWS	33	51	up 725%	67%
Warwick Bridge PS Storm discharge at pumping station Company site name Warwick Bridge PS EA ID / permit UUP02031 · 017680331 Outlet location NY4737056940 (OS grid reference) · View on Apple Maps WFD catchment Trout Beck (Cairn Beck) (GB102076073900) 2024 spills / hours 27 / 50 Long-term average 23.0 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 50 hours spilling →	Cairn Beck	28	50	up 4%	100%
Manchester Rd/Park Lane CSO Overflow on sewer network Company site name Manchester Road/Park Lane CSO EA ID / permit UUP01232 · 01WIG0199 Outlet location SJ6721099720 (OS grid reference) · View on Apple Maps WFD catchment Bedford Brook (GB112069060810) 2024 spills / hours 27 / 59 Long-term average 39.8 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement Env Act (SODRP) improvement ongoing Volume & pollution Estimate from 50 hours spilling →	Bedford Brook	23	50	down 15%	100%
Hyde Road (Denton) CSO Overflow on sewer network Company site name HYDE ROAD Denton CSO EA ID / permit UUP01010 · 01TAM0069 Outlet location SJ9370895365 (OS grid reference) · View on Apple Maps WFD catchment Tame (Swineshaw Brook to Mersey) (GB112069061112) 2024 spills / hours 52 / 84 Long-term average 60.6 spills a year (monitored since 2021) High-spill reason (company) Not asset maintenance - Hydraulic capacity Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 50 hours spilling →	River Tame	40	50	down 23%	100%
Rolls Crescent/Yew Street CSO Overflow on sewer network Company site name Rolls Crescent/Yew Street CSO EA ID / permit UUP01682 · 016982958 Outlet location SJ8252097363 (OS grid reference) · View on Apple Maps WFD catchment Irwell / Manchester Ship Canal (Irk to confluence with Upper Mersey) (GB112069061452) 2024 spills / hours 18 / 45 Long-term average 16.8 spills a year (monitored since 2021) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 50 hours spilling →	Manchester Ship Canal via SWS	14	50	down 22%	100%
Station Hill CSO Overflow on sewer network Company site name Station Hill CSO EA ID / permit UUP01847 · 017580225 Outlet location NY2539048820 (OS grid reference) · View on Apple Maps WFD catchment Wiza Beck (GB102075073390) 2024 spills / hours 23 / 28 Long-term average 22.7 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement Env Act (SODRP) improvement ongoing Volume & pollution Estimate from 50 hours spilling →	Wiza Beck	25	50	up 9%	100%
Queensway CSO Overflow on sewer network Company site name The Queensway CSO EA ID / permit UUP01599 · 016892228 Outlet location SD7915001870 (OS grid reference) · View on Apple Maps WFD catchment Irwell (Croal to Irk) (GB112069061451) 2024 spills / hours 22 / 44 Long-term average 25.9 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 49 hours spilling →	Slack Brook via Suface Water S	14	49	down 36%	100%
Tbc Inlet overflow at sewage works Sewage works Tbc Company site name Cocklakes WwTW EA ID / permit UUP02275 · Unpermitted Outlet location NY4620051100 (OS grid reference) · View on Apple Maps WFD catchment Pow Maughan Beck (GB102076073910) 2024 spills / hours 134 / 383 Long-term average 6.0 spills a year (monitored since 2024) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 49 hours spilling →	Trib Pow Maughan Beck	6	49	down 96%	100%
Heads Nook WwTW Inlet overflow at sewage works Sewage works Heads Nook Company site name HEADS NOOK WwTW EA ID / permit UUP00931 · 017670062 Outlet location NY4903055070 (OS grid reference) · View on Apple Maps WFD catchment Cairn Beck (GB102076073870) 2024 spills / hours 26 / 76 Long-term average 61.5 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement Env Act (SODRP) improvement ongoing Volume & pollution Estimate from 49 hours spilling →	Cairn Beck	22	49	down 15%	100%
Queens Park Road CSO Overflow on sewer network Company site name Queens Park Road CSO EA ID / permit UUP01594 · EPRJP3122XY Outlet location SD6934827603 (OS grid reference) · View on Apple Maps WFD catchment Blakewater (GB112071065310) 2024 spills / hours 19 / 48 Long-term average 32.5 spills a year (monitored since 2020) High-spill reason (company) Not asset maintenance - Hydraulic capacity Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 49 hours spilling →	Queens Park Culvert	33	49	up 74%	100%
Oughterby Pumping Station Storm discharge at pumping station Company site name Oughterby Pumping Station (Site ID 02587) (ALL0067) EA ID / permit UUP01483 · 01ALL0067 Outlet location NY2921055660 (OS grid reference) · View on Apple Maps WFD catchment SOLWAY (GB530207614700) 2024 spills / hours 9 / 55 Long-term average 6.7 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 49 hours spilling →	Unnamed Trib. of Grass Dyke	7	49	down 22%	100%
Ribchester WwTW Storm tank at sewage works Sewage works Ribchester Company site name RIBCHESTER WwTW EA ID / permit UUP01650 · 017160043 Outlet location SD6516034401 (OS grid reference) · View on Apple Maps WFD catchment Ribble - conf Calder to tidal (GB112071065500) 2024 spills / hours 8 / 37 Long-term average 46.3 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 49 hours spilling →	River Ribble	6	49	down 25%	98%
Bradeley Hall Road CSO Overflow on sewer network Company site name Bradeley Hall Road CSO EA ID / permit UUP00293 · 016810325 Outlet location SJ7284256238 (OS grid reference) · View on Apple Maps WFD catchment Fowle Brook (GB112068055400) 2024 spills / hours 29 / 50 Long-term average 28.0 spills a year (monitored since 2021) Investigation Operational investigation completed Improvement Operational improvement completed Volume & pollution Estimate from 49 hours spilling →	Fowle Brook via SWS	24	49	down 17%	95%
Bickerstaffe W.Water Pump Station Storm discharge at pumping station Company site name Bickerstaffe Wastewater PS EA ID / permit UUP00231 · 016930107 Outlet location SD4373004370 (OS grid reference) · View on Apple Maps WFD catchment Downholland (Lydiate/Cheshires Lines) Brook (GB112069060640) 2024 spills / hours 12 / 40 Long-term average 10.0 spills a year (monitored since 2024) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 49 hours spilling →	Bickerstaffe Brook	8	49	down 33%	100%
Buffalo Court Detention Tank Overflow on sewer network Company site name BUFFALO COURT DETENTION TANK (37066) EA ID / permit UUP00359 · EPRDB3690DM Outlet location SJ8013097730 (OS grid reference) · View on Apple Maps WFD catchment Irwell / Manchester Ship Canal (Irk to confluence with Upper Mersey) (GB112069061452) 2024 spills / hours 20 / 116 Long-term average 14.5 spills a year (monitored since 2024) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 49 hours spilling →	Manchester Ship Canal	9	49	down 55%	100%
Thornton Road Depot CSO 482U7 Overflow on sewer network Company site name Thornton Road Depot CSO EA ID / permit UUP01935 · 01WAR0013 Outlet location SJ5776087340 (OS grid reference) · View on Apple Maps WFD catchment MERSEY - Transitional (GB531206908100) 2024 spills / hours 35 / 41 Long-term average 58.6 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 49 hours spilling →	Sankey Brook	15	49	down 57%	100%
Oakfield St Combined Sewer Overflow Overflow on sewer network Company site name Oakfield Street CSO EA ID / permit UUP01432 · 016892327 Outlet location SJ7744087990 (OS grid reference) · View on Apple Maps WFD catchment Timperley Brook (GB112069061260) 2024 spills / hours 40 / 49 Long-term average 45.5 spills a year (monitored since 2020) Investigation Env Act (SODRP) investigation ongoing, Operational investigation completed Improvement Operational improvement completed Volume & pollution Estimate from 48 hours spilling →	Timperley Brook	26	48	down 35%	99%
Culgaith WwTW Storm tank at sewage works Sewage works Culgaith Company site name CULGAITH WwTW EA ID / permit UUP00592 · 017670167 Outlet location NY6010029500 (OS grid reference) · View on Apple Maps WFD catchment Eden Lyvennet to Eamont (GB102076070980) 2024 spills / hours 21 / 106 Long-term average 21.5 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 48 hours spilling →	River Eden	9	48	down 57%	100%
Opp West View Combined Sewer O/Flow Overflow on sewer network Company site name Opp West View CSO EA ID / permit UUP01468 · 01ALL0012 Outlet location NY1752050520 (OS grid reference) · View on Apple Maps WFD catchment Waver (GB102075073440) 2024 spills / hours 12 / 26 Long-term average 17.2 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 48 hours spilling →	Stank Beck	16	48	up 33%	100%
Roa Island Pumping Station Storm discharge at pumping station Company site name Roa Island PS EA ID / permit UUP01665 · 017480366 Outlet location SD2318164600 (OS grid reference) · View on Apple Maps WFD catchment Morecambe Bay - transitional (GB641211171000) Bathing water Walney Biggar Bank Shellfish water Roosebeck 2024 spills / hours 57 / 161 Long-term average 77.3 spills a year (monitored since 2017) Monitor below 90% Sensor failure / issue · Resolved - January after reporting year Investigation No investigation activity in reporting period Improvement Env Act (SODRP) improvement ongoing Volume & pollution Estimate from 48 hours spilling →	Piel Channel	23	48	down 60%	76%
The Avenue (Churchtown) CSO Overflow on sewer network Company site name The Avenue (churchtown) CSO EA ID / permit UUP01908 · 017290551 Outlet location SD4877042970 (OS grid reference) · View on Apple Maps WFD catchment Wyre DS Grizedale Brook confl (GB112072065822) 2024 spills / hours 15 / 90 Long-term average 10.4 spills a year (monitored since 2021) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 48 hours spilling →	River Wyre	10	48	down 33%	95%
273 Regent St CSO (32013) Overflow on sewer network Company site name Rear of 273 Regent Street CSO EA ID / permit UUP00026 · 01PEN0006 Outlet location SD8681039160 (OS grid reference) · View on Apple Maps WFD catchment Colne Water - Wanless Water to Pendle Water (GB112071065150) 2024 spills / hours 25 / 105 Long-term average 27.0 spills a year (monitored since 2021) Investigation Operational investigation completed Improvement Operational improvement completed Volume & pollution Estimate from 48 hours spilling →	Swinden Clough	9	48	down 64%	100%
Smith St and John St CSO 35021 Overflow on sewer network Company site name Junction of Smith Street/John Street CSO EA ID / permit UUP01774 · 016993536 Outlet location SD9011013440 (OS grid reference) · View on Apple Maps WFD catchment Roch (Source to Spodden) (GB112069064720) 2024 spills / hours 32 / 26 Long-term average 45.3 spills a year (monitored since 2019) High-spill reason (company) Not asset maintenance - Hydraulic capacity Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 48 hours spilling →	River Roch	34	48	up 6%	99%
Reeman Court Manhole H4 CSO 272NY Overflow on sewer network Company site name Reeman Court (Manhole H4) EA ID / permit UUP01644 · EPRJB3298WZ Outlet location SJ8449382562 (OS grid reference) · View on Apple Maps WFD catchment Dean (Bollington to Bollin) (GB112069061360) 2024 spills / hours 16 / 49 Long-term average 43.3 spills a year (monitored since 2019) Investigation Operational investigation completed Improvement Operational improvement completed Volume & pollution Estimate from 48 hours spilling →	River Dean	9	48	down 44%	99%
Molyneux Drive CSO 24009 Overflow on sewer network Company site name Molyneux Drive CSO EA ID / permit UUP01333 · 016993826 Outlet location SJ4581090940 (OS grid reference) · View on Apple Maps WFD catchment Prescot Brook (Logwood Mill Brook) (GB112069060710) 2024 spills / hours 34 / 59 Long-term average 55.4 spills a year (monitored since 2019) High-spill reason (company) Not asset maintenance - Hydraulic capacity Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 47 hours spilling →	Prescot Brook	38	47	up 12%	100%
Skelmersdale WwTW Inlet overflow at sewage works Sewage works Skelmersdale Company site name SKELMERSDALE WwTW EA ID / permit UUP01761 · 017020107 Outlet location SD4817412024 (OS grid reference) · View on Apple Maps WFD catchment Douglas - Lower (GB112070064820) Bathing water St Annes Shellfish water Ribble 2024 spills / hours 24 / 83 Long-term average 43.2 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 47 hours spilling →	River Douglas	14	47	down 42%	96%
Bidston by-Pass CSO Overflow on sewer network Company site name Bidston Bypass CSO EA ID / permit UUP00234 · 016892425 Outlet location SJ2845090890 (OS grid reference) · View on Apple Maps WFD catchment The Birket including Arrowe Brook and Fender (GB112068060530) Bathing water Wallasey Shellfish water North Wirral (East) 2024 spills / hours 22 / 19 Long-term average 87.0 spills a year (monitored since 2019) Monitor below 90% Sensor failure / issue · Resolved - Jul Investigation Env Act (SODRP) investigation ongoing Improvement Env Act (SODRP) improvement ongoing Volume & pollution Estimate from 47 hours spilling →	River Birket	13	47	down 41%	72%
Hanging Green Lane CSO LAN0123 Overflow on sewer network Company site name Hanging Green Lane CSO (258G9) EA ID / permit UUP02213 · EPRJB3894RC Outlet location SD4726266573 (OS grid reference) · View on Apple Maps WFD catchment Lune - conf Wenning to tidal (GB112072065980) 2024 spills / hours 32 / 37 Long-term average 31.5 spills a year (monitored since 2024) High-spill reason (company) Not asset maintenance - Hydraulic capacity Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 47 hours spilling →	Hatlex Beck Via a surface water sewer	31	47	down 3%	99%
Watford Bridge CSO 212W1 Overflow on sewer network Company site name Watford Bridge CSO EA ID / permit UUP02059 · 016982636 Outlet location SK0055086410 (OS grid reference) · View on Apple Maps WFD catchment Sett (GB112069060970) 2024 spills / hours 26 / 78 Long-term average 44.3 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement Env Act (SODRP) improvement ongoing Volume & pollution Estimate from 47 hours spilling →	River Sett	23	47	down 12%	97%
Mauldeth Road West CSO (28043) Overflow on sewer network Company site name Mauldeth Road West CSO EA ID / permit UUP01264 · 01MAN0230 Outlet location SJ8340093650 (OS grid reference) · View on Apple Maps WFD catchment Chorlton Brook (Princess Parkway to Mersey) (GB112069061040) 2024 spills / hours 19 / 39 Long-term average 39.4 spills a year (monitored since 2021) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 47 hours spilling →	Chorlton Brook via Culvert	26	47	up 37%	100%
Garstang Road/Bilsborrow PS Storm discharge at pumping station Company site name Garstang Road, Bilsborrow PS EA ID / permit UUP00776 · 017280326 Outlet location SD5095039680 (OS grid reference) · View on Apple Maps WFD catchment New Draught Brook (GB112072065790) 2024 spills / hours 13 / 125 Long-term average 27.3 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 47 hours spilling →	Bacchus Brook	4	47	down 69%	100%
Rosthwaite WwTW Inlet overflow at sewage works Sewage works Rosthwaite Company site name ROSTHWAITE WwTW EA ID / permit UUP01690 · 017570053 Outlet location NY2548015050 (OS grid reference) · View on Apple Maps WFD catchment Derwent - headwaters to conf Stonethwaite Beck (GB112075070330) 2024 spills / hours 30 / 69 Long-term average 33.5 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 47 hours spilling →	Trib of River Derwent	21	47	down 30%	99%
Lime Tree Close CSO Overflow on sewer network Company site name Lime Tree Close CSO EA ID / permit UUP01143 · 016940381 Outlet location SJ7714093810 (OS grid reference) · View on Apple Maps WFD catchment Mersey (upstream of Manchester Ship Canal) (GB112069061030) 2024 spills / hours 14 / 38 Long-term average 13.4 spills a year (monitored since 2021) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 46 hours spilling →	River Mersey	11	46	down 21%	99%
Lomeshaye Way CSO Overflow on sewer network Company site name Lomeshaye Way CSO EA ID / permit UUP01170 · 017180488 Outlet location SD8513037900 (OS grid reference) · View on Apple Maps WFD catchment Calder - Pendle Water to conf Ribble (GB112071065490) 2024 spills / hours 28 / 75 Long-term average 29.2 spills a year (monitored since 2021) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 46 hours spilling →	Pendle Water	19	46	down 32%	100%
Armathwaite WwTW Inlet overflow at sewage works Sewage works Armathwaite Company site name ARMATHWAITE WwTW EA ID / permit UUP00133 · 017670054 Outlet location NY5107046370 (OS grid reference) · View on Apple Maps WFD catchment Eden - Eamont to tidal (GB102076073940) 2024 spills / hours 146 / 147 Long-term average 106.5 spills a year (monitored since 2018) High-spill reason (company) Not asset maintenance - Hydraulic capacity Investigation Env Act (SODRP) investigation ongoing Improvement Env Act (SODRP) improvement ongoing Volume & pollution Estimate from 46 hours spilling →	River Eden	67	46	down 54%	99%
Lane Bottom STW Inlet overflow at sewage works Sewage works Lane Bottom Company site name Lanebottom WwTW EA ID / permit UUP02269 · Unpermitted Outlet location SD8760035800 (OS grid reference) · View on Apple Maps WFD catchment Walverden Water (GB112071065130) 2024 spills / hours 30 / 94 Long-term average 24.5 spills a year (monitored since 2024) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 46 hours spilling →	Pig Hole Clough	19	46	down 37%	93%
Arbour Lane Pumping Station Storm discharge at pumping station Company site name Arbour Lane Pumping Station (50033) (WIG0029 ) EA ID / permit UUP00127 · 017091563 Outlet location SD5503009730 (OS grid reference) · View on Apple Maps WFD catchment Douglas - Lower (GB112070064820) 2024 spills / hours 15 / 58 Long-term average 22.2 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 46 hours spilling →	Mill Brook	14	46	down 7%	100%
Bolton Road Combined Sewer Overflow Overflow on sewer network Company site name Bolton Road CSO EA ID / permit UUP00270 · NPSWQD010684 Outlet location SD6769026340 (OS grid reference) · View on Apple Maps WFD catchment Darwen - headwaters to conf Davy Field Bk (GB112071065240) 2024 spills / hours 54 / 59 Long-term average 48.5 spills a year (monitored since 2020) High-spill reason (company) Not asset maintenance - Hydraulic capacity Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 46 hours spilling →	Unnamed Trib of River Darwen	45	46	down 17%	100%
Robin Hood Clifton Pumping Station Storm discharge at pumping station Company site name Robin Hood (Clifton) PS EA ID / permit UUP01667 · 016993828 Outlet location SD7845003556 (OS grid reference) · View on Apple Maps WFD catchment Irwell (Croal to Irk) (GB112069061451) 2024 spills / hours 16 / 46 Long-term average 12.8 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 46 hours spilling →	River Irwell via SWS	7	46	down 56%	97%
Nearer Holker House Farm PS (22012) Storm discharge at pumping station Company site name Nearer Holker House Farm EA ID / permit UUP00999 · 01HYN0050 Outlet location SD7695030690 (OS grid reference) · View on Apple Maps WFD catchment Calder - Pendle Water to conf Ribble (GB112071065490) 2024 spills / hours 6 / 16 Long-term average 15.5 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 45 hours spilling →	Clough Brook	17	45	up 183%	100%
Dibbs Lane CSO 381RT Overflow on sewer network Company site name O/S 32 Hall Road East CSO EA ID / permit UUP00639 · 016982651 Outlet location SD2955001650 (OS grid reference) · View on Apple Maps WFD catchment MERSEY MOUTH - transitional (GB641211630001) Bathing water Formby 2024 spills / hours 58 / 93 Long-term average 57.1 spills a year (monitored since 2018) High-spill reason (company) Not asset maintenance - Hydraulic capacity Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 45 hours spilling →	River Mersey Estuary	37	45	down 36%	99%

Sewage treatment works

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

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