Storm overflow register · 2025 annual return

Thames Water storm overflows, 2025

Thames Water reported 581 storm overflows in England for 2025. Together they recorded 9,189 spills over 107,822 hours, an average of 15.8 spills per overflow against 20.4 across England. That ranks 3 of 10 companies, where 1 is the fewest spills per overflow. Counting the same overflows in both years, spills were down 60% on 2024.

135 overflows did not spill · 28 spilled more than 60 times · 548 had monitors working for 90% of the year or more · 233 sewage treatment works with overflows

Hours spilling by month, 2025

010k20k30k40kJan 2025: 37,152 hours spillingJanFeb 2025: 23,894 hours spillingFebMar 2025: 7,398 hours spillingMarApr 2025: 2,669 hours spillingAprMay 2025: 809 hours spillingMayJun 2025: 213 hours spillingJunJul 2025: 854 hours spillingJulAug 2025: 258 hours spillingAugSep 2025: 754 hours spillingSepOct 2025: 1,381 hours spillingOctNov 2025: 8,586 hours spillingNovDec 2025: 23,856 hours spillingDec
Hours spilling, all Thames Water overflows, from the start/stop records. Spills running across a month end are split between the months.

All Thames Water storm overflows

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

OverflowDischarges toSpills 2025Hours 2025Spills vs 2024Monitor uptime
Avondale Road
Storm discharge at pumping station
Company site name
Avondale Road (Fleet) SPS
EA ID / permit
TWL00021 · TEMP.0376
Outlet location
SU8180054600 (OS grid reference) · View on Apple Maps
WFD catchment
Fleet Brook (GB106039017120)
2024 spills / hours
0 / 0.0
Long-term average
2.1 spills a year (monitored since 2018)
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
Fleet Brook 0 0.0 no change 98%
Bell Wharf CSO
Overflow on sewer network
Company site name
Bell wharf
EA ID / permit
TWL00033 · CSAB.0526
Outlet location
TQ3563080710 (OS grid reference) · View on Apple Maps
WFD catchment
THAMES MIDDLE (GB530603911402)
2024 spills / hours
7 / 4.7
Long-term average
6.9 spills a year (monitored since 2019)
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
Tidal Riverthames 0 0.0 down 100% 100%
Bentsbrook Road SWS
Overflow on sewer network
Company site name
Bentsbrook road
EA ID / permit
TWL00738 · CTCR.1923
Outlet location
TQ1769047490 (OS grid reference) · View on Apple Maps
WFD catchment
Tanners Brook (Holmewood to River Mole confluence at Brockham) (GB106039017570)
2024 spills / hours
4 / 8.0
Long-term average
1.7 spills a year (monitored since 2023)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
Tanners Brook (Bents Brook) 0 0.0 down 100% 100%
Birchanger - Duck End
Storm discharge at pumping station
Company site name
Duck End (Bishops Stortford) SPS
EA ID / permit
TWL00039 · TEMP.0455
Outlet location
TL5150021800 (OS grid reference) · View on Apple Maps
WFD catchment
Great Hallingbury Brook (GB106038033330)
2024 spills / hours
0 / 0.0
Long-term average
0.0 spills a year (monitored since 2019)
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
Great Hallingbury Brook 0 0.0 no change 100%
Brentfield Gardens CSO A
Overflow on sewer network
Company site name
Brentfield gardens
EA ID / permit
TWL00491 · TEMP.2413
Outlet location
TQ2357087980 (OS grid reference) · View on Apple Maps
WFD catchment
Dollis Brook and Upper Brent (GB106039022980)
2024 spills / hours
0 / 0.0
Long-term average
6.1 spills a year (monitored since 2019)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
River Brent 0 0.0 no change 95%
Bucknell Pumping Station
Storm discharge at pumping station
Company site name
XX (Bucknell) SPS
EA ID / permit
TWL00498 · CNTM.0214
Outlet location
SP5653025690 (OS grid reference) · View on Apple Maps
WFD catchment
Town Brook at Bicester (GB106039030150)
2024 spills / hours
7 / 55
Long-term average
3.5 spills a year (monitored since 2023)
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
Town Brook 0 0.0 down 100% 94%
Canfield End, Little Canfield
Storm discharge at pumping station
Company site name
Canfield End (Takeley) SPS
EA ID / permit
TWL00071 · TEMP.0596
Outlet location
TL5850021301 (OS grid reference) · View on Apple Maps
WFD catchment
Upper Roding (to Cripsey Brook) (GB106037033500)
2024 spills / hours
1 / 6.0
Long-term average
8.1 spills a year (monitored since 2019)
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
Roding 0 0.0 down 100% 100%
Canterbury Road, Thornton Heath
Overflow on sewer network
Company site name
Canterbury road, thornton heath
EA ID / permit
TWL00073 · TEMP.2514
Outlet location
TQ3130066900 (OS grid reference) · View on Apple Maps
WFD catchment
Wandle (Croydon to Wandsworth) and the Graveney (GB106039023460)
2024 spills / hours
2 / 3.3
Long-term average
1.7 spills a year (monitored since 2019)
Monitor below 90%
Comms failure / issue · Resolved - Nov
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
Wandle 0 0.0 down 100% 87%
Cassington (New)
Storm tank at sewage works
Sewage works
Cassington
Company site name
Cassington STW
EA ID / permit
TWL00075 · TEMP.2457
Outlet location
SP4660010100 (OS grid reference) · View on Apple Maps
WFD catchment
Thames (Evenlode to Thame) (GB106039030334)
Bathing water
Wolvercote Mill Stream
2024 spills / hours
22 / 337
Long-term average
15.3 spills a year (monitored since 2019)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
Thames 0 0.0 down 100% 100%
Castle Drive
Storm discharge at pumping station
Company site name
Castle Drive (Reigate) SPS
EA ID / permit
TWL00076 · TEMP.0615
Outlet location
TQ2540048000 (OS grid reference) · View on Apple Maps
WFD catchment
Mole - Horley to Dorking (GB106039017625)
2024 spills / hours
10 / 36
Long-term average
3.4 spills a year (monitored since 2019)
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
Norman'S Gill 0 0.0 down 100% 100%
Charlton Storm Relief CSO
Overflow on sewer network
Company site name
Charlton storm relief (B)
EA ID / permit
TWL00505 · CSAB.0551
Outlet location
TQ4126079230 (OS grid reference) · View on Apple Maps
WFD catchment
THAMES MIDDLE (GB530603911402)
2024 spills / hours
0 / 0.0
Long-term average
20.5 spills a year (monitored since 2020)
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
R.Thames ( Tidal ) 0 0.0 no change 100%
Charlton Storm Relief CSO
Overflow on sewer network
Company site name
Charlton storm relief (A)
EA ID / permit
TWL00084 · CSAB.0551
Outlet location
TQ4126079230 (OS grid reference) · View on Apple Maps
WFD catchment
THAMES MIDDLE (GB530603911402)
2024 spills / hours
2 / 1.0
Long-term average
15.8 spills a year (monitored since 2020)
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
R.Thames ( Tidal ) 0 0.0 down 100% 100%
Charlton Storm Relief CSO
Overflow on sewer network
Company site name
Charlton storm relief (C)
EA ID / permit
TWL00506 · CSAB.0551
Outlet location
TQ4126079230 (OS grid reference) · View on Apple Maps
WFD catchment
THAMES MIDDLE (GB530603911402)
2024 spills / hours
1 / 0.5
Long-term average
15.2 spills a year (monitored since 2020)
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
R.Thames ( Tidal ) 0 0.0 down 100% 100%
Chieveley
Storm tank at sewage works
Sewage works
Chieveley
Company site name
Chieveley STW
EA ID / permit
TWL00090 · TEMP.2475
Outlet location
SU4690073901 (OS grid reference) · View on Apple Maps
WFD catchment
Winterbourne (GB106039023210)
2024 spills / hours
7 / 46
Long-term average
4.3 spills a year (monitored since 2019)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
Winterbourne Stream 0 0.0 down 100% 100%
Chigwell Road, Woodford Green
Overflow on sewer network
Company site name
WINN VALLEY SPS LB REDBRIDGE 6 (ARUNDEL DRIVE) TQ40913107 CSO
EA ID / permit
TWL00787 · CETR.0232
Outlet location
TQ4160091300 (OS grid reference) · View on Apple Maps
WFD catchment
Lower Roding (Loughton to Thames) (GB106037028181)
2024 spills / hours
1 / 0.1
Long-term average
0.3 spills a year (monitored since 2023)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
Roding 0 0.0 down 100% 100%
Chigwell Road, Woodford Green
Overflow on sewer network
Company site name
WINN VALLEY SPS LB REDBRIDGE 4 (SALWAY GARDENS) TQ40914102 CSO
EA ID / permit
TWL00785 · CETR.0232
Outlet location
TQ4160091300 (OS grid reference) · View on Apple Maps
WFD catchment
Lower Roding (Loughton to Thames) (GB106037028181)
2024 spills / hours
0 / 0.0
Long-term average
0.0 spills a year (monitored since 2023)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
Roding 0 0.0 no change 100%
Chingford Storm Tanks
Overflow on sewer network
Company site name
Chingford storm tanks
EA ID / permit
TWL00092 · TEMP.2520
Outlet location
TQ3710091800 (OS grid reference) · View on Apple Maps
WFD catchment
Ching Brook (GB106038027930)
2024 spills / hours
2 / 4.8
Long-term average
2.1 spills a year (monitored since 2019)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
Lee 0 0.0 down 100% 100%
Colgate Wastewater Treatment Works
Inlet overflow at sewage works
Sewage works
Colgate
Company site name
Colgate STW
EA ID / permit
TWL00109 · TEMP.2495
Outlet location
TQ2320033020 (OS grid reference) · View on Apple Maps
WFD catchment
Ifield Brook (GB106039017460)
2024 spills / hours
0 / 0.0
Long-term average
21.0 spills a year (monitored since 2019)
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
Ifield Brook 0 0.0 no change 100%
CSO at Barbers Lane
Overflow on sewer network
Company site name
Barbers lane
EA ID / permit
TWL00026 · TEMP.2431
Outlet location
TL0922021380 (OS grid reference) · View on Apple Maps
WFD catchment
Lee (from Luton to Luton Hoo Lakes) (GB106038033391)
2024 spills / hours
0 / 0.0
Long-term average
1.1 spills a year (monitored since 2019)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
Lee 0 0.0 no change 100%
CSO at Field End Road Storm
Overflow on sewer network
Company site name
Field end rd storm (harrow)
EA ID / permit
TWL00128 · TEMP.2592
Outlet location
TQ1235085740 (OS grid reference) · View on Apple Maps
WFD catchment
Yeading Brook (GB106039023051)
2024 spills / hours
3 / 9.3
Long-term average
1.1 spills a year (monitored since 2018)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
Yeading Brook East 0 0.0 down 100% 100%
CSO at Gap Road (Cemetery)
Overflow on sewer network
Company site name
Wimbledon Hill Road
EA ID / permit
TWL00766 · TEMP.2630
Outlet location
TQ2586071870 (OS grid reference) · View on Apple Maps
WFD catchment
Wandle (Croydon to Wandsworth) and the Graveney (GB106039023460)
2024 spills / hours
1 / 1.0
Long-term average
0.3 spills a year (monitored since 2023)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
River Wandle 0 0.0 down 100% 100%
CSO at Gap Road (Cemetery)
Overflow on sewer network
Company site name
Wimbledon Hill Wimbledon
EA ID / permit
TWL00767 · TEMP.2630
Outlet location
TQ2586071870 (OS grid reference) · View on Apple Maps
WFD catchment
Wandle (Croydon to Wandsworth) and the Graveney (GB106039023460)
2024 spills / hours
1 / 0.1
Long-term average
0.3 spills a year (monitored since 2023)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
River Wandle 0 0.0 down 100% 100%
CSO at Gap Road (Cemetery)
Overflow on sewer network
Company site name
Gap road (cemetery)
EA ID / permit
TWL00129 · TEMP.2630
Outlet location
TQ2586071870 (OS grid reference) · View on Apple Maps
WFD catchment
Wandle (Croydon to Wandsworth) and the Graveney (GB106039023460)
2024 spills / hours
2 / 1.0
Long-term average
0.4 spills a year (monitored since 2018)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
River Wandle 0 0.0 down 100% 100%
CSO at Markenfield Road
Overflow on sewer network
Company site name
Markenfield road, guildford
EA ID / permit
TWL00135 · TEMP.2792
Outlet location
SU9928050320 (OS grid reference) · View on Apple Maps
WFD catchment
Wey (Shalford to River Thames confluence at Weybridge) (GB106039017630)
2024 spills / hours
1 / 0.1
Long-term average
0.4 spills a year (monitored since 2019)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
River Wey 0 0.0 down 100% 100%
CSO at New Bedford Road
Overflow on sewer network
Company site name
New bedford road, luton
EA ID / permit
TWL00137 · CANM.0550
Outlet location
TL0886021690 (OS grid reference) · View on Apple Maps
WFD catchment
Lee (from Luton to Luton Hoo Lakes) (GB106038033391)
2024 spills / hours
4 / 11
Long-term average
1.1 spills a year (monitored since 2019)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
River Lee 0 0.0 down 100% 98%
CSO at Oakentrough
Overflow on sewer network
Company site name
Oakentrough
EA ID / permit
TWL00138 · CANM.0029
Outlet location
TQ4354083230 (OS grid reference) · View on Apple Maps
WFD catchment
THAMES MIDDLE (GB530603911402)
2024 spills / hours
11 / 17
Long-term average
12.6 spills a year (monitored since 2019)
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
River Roding 0 0.0 down 100% 100%
CSO at Penwith Road
Overflow on sewer network
Company site name
Penwith road
EA ID / permit
TWL00139 · TEMP.2841
Outlet location
TQ2588073040 (OS grid reference) · View on Apple Maps
WFD catchment
Wandle (Croydon to Wandsworth) and the Graveney (GB106039023460)
2024 spills / hours
1 / 1.5
Long-term average
0.9 spills a year (monitored since 2018)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
River Wandle 0 0.0 down 100% 100%
CSO at Vauxhall Motors
Overflow on sewer network
Company site name
Vauxhall motors
EA ID / permit
TWL00144 · TEMP.2984
Outlet location
TL0991020730 (OS grid reference) · View on Apple Maps
WFD catchment
Lee (from Luton to Luton Hoo Lakes) (GB106038033391)
2024 spills / hours
7 / 8.3
Long-term average
2.6 spills a year (monitored since 2018)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
River Lee / Lea 0 0.0 down 100% 100%
Dartford Creek Storm
Overflow on sewer network
Company site name
Dartford creek storm
EA ID / permit
TWL00150 · TEMP.2537
Outlet location
TQ5370075500 (OS grid reference) · View on Apple Maps
WFD catchment
THAMES MIDDLE (GB530603911402)
2024 spills / hours
– / –
Long-term average
2.0 spills a year (monitored since 2020)
Monitor below 90%
Installation set-up/design issue · Not Applicable - Ongoing investigation
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
Darent/dartford Creek – – 0%
Dean Oak Lane
Storm discharge at pumping station
Company site name
Dean Oak Lane (Leigh) SPS
EA ID / permit
TWL00151 · TEMP.0822
Outlet location
TQ2380045300 (OS grid reference) · View on Apple Maps
WFD catchment
Deanoak Brook (GB106039017530)
2024 spills / hours
0 / 0.0
Long-term average
1.9 spills a year (monitored since 2019)
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
Deanoak Brook 0 0.0 no change 100%
Draycott Foliat
Storm discharge at pumping station
Company site name
Draycot Foliat SPS
EA ID / permit
TWL00161 · TEMP.0856
Outlet location
SU1870077700 (OS grid reference) · View on Apple Maps
WFD catchment
Og (GB106039023180)
2024 spills / hours
1 / 8.0
Long-term average
0.3 spills a year (monitored since 2018)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
River Ray 0 0.0 down 100% 100%
East Garston
Storm discharge at pumping station
Company site name
East Garston SPS
EA ID / permit
TWL00165 · TEMP.0882
Outlet location
SU3670076400 (OS grid reference) · View on Apple Maps
WFD catchment
Lambourn (Source to Newbury) (GB106039023220)
2024 spills / hours
0 / 0.0
Long-term average
37.0 spills a year (monitored since 2019)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
River Lambourn 0 0.0 no change 100%
Eastcote Avenue
Overflow on sewer network
Company site name
Eastcote avenue
EA ID / permit
TWL00168 · TEMP.2580
Outlet location
TQ1648084980 (OS grid reference) · View on Apple Maps
WFD catchment
Lower Brent (GB106039023590)
2024 spills / hours
2 / 5.5
Long-term average
1.0 spills a year (monitored since 2019)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
Wembley Brook 0 0.0 down 100% 97%
Elmcroft Avenue,
Overflow on sewer network
Company site name
THE DRIVE TQ4089171A CSO
EA ID / permit
TWL00170 · CANM.0910
Outlet location
TQ4140089300 (OS grid reference) · View on Apple Maps
WFD catchment
Lower Roding (Loughton to Thames) (GB106037028181)
2024 spills / hours
0 / 0.0
Long-term average
0.3 spills a year (monitored since 2023)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
The River Roding 0 0.0 no change 100%
Essendon, Holywell Bridge
Storm discharge at pumping station
Company site name
Essendon SPS
EA ID / permit
TWL00175 · TEMP.0924
Outlet location
TL2760009700 (OS grid reference) · View on Apple Maps
WFD catchment
Lee (from Luton Hoo Lakes to Hertford) (GB106038033392)
2024 spills / hours
17 / 63
Long-term average
5.3 spills a year (monitored since 2019)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
Lea 0 0.0 down 100% 100%
Ewhurst Road
Overflow on sewer network
Company site name
Ewhurst road, cranleigh, surrey
EA ID / permit
TWL00570 · CTCR.1927
Outlet location
TQ0650039400 (OS grid reference) · View on Apple Maps
WFD catchment
Cranleigh Waters (GB106039017810)
2024 spills / hours
0 / 0.0
Long-term average
0.0 spills a year (monitored since 2023)
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
Littlemead Brook 0 0.0 no change 100%
Fergusson Road, Banbury
Overflow on sewer network
Company site name
Fergusson road, banbury
EA ID / permit
TWL00183 · TEMP.2606
Outlet location
SP4616041200 (OS grid reference) · View on Apple Maps
WFD catchment
Cherwell (Cropredy to Nell Bridge) (GB106039037310)
2024 spills / hours
5 / 28
Long-term average
2.9 spills a year (monitored since 2019)
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
Cherwell 0 0.0 down 100% 100%
Foul Sewer Overflow
Overflow on sewer network
Company site name
Coppice green, bracknell
EA ID / permit
TWL00189 · CTCR.1999
Outlet location
SU8589070410 (OS grid reference) · View on Apple Maps
WFD catchment
Cut (Binfield to River Thames confluence) and Maidenhead Ditch (GB106039023510)
2024 spills / hours
0 / 0.0
Long-term average
3.4 spills a year (monitored since 2018)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
The Cut 0 0.0 no change 100%
Fyfield Wastewater Treatment Works
Storm tank at sewage works
Sewage works
Fyfield
Company site name
Fyfield STW
EA ID / permit
TWL00193 · CNTD.0046
Outlet location
SU1508068370 (OS grid reference) · View on Apple Maps
WFD catchment
Upper Kennet to Marlborough (GB106039023171)
2024 spills / hours
44 / 994
Long-term average
28.7 spills a year (monitored since 2019)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
River Kennet 0 0.0 down 100% 100%
Garden Way CSO
Overflow on sewer network
Company site name
Garden way
EA ID / permit
TWL00194 · TEMP.2610
Outlet location
TQ1998084510 (OS grid reference) · View on Apple Maps
WFD catchment
Lower Brent (GB106039023590)
2024 spills / hours
0 / 0.0
Long-term average
0.0 spills a year (monitored since 2020)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
River Brent 0 0.0 no change 100%
Gascoigne Road
Storm discharge at pumping station
Company site name
Gascoigne Road (Barking) SPS
EA ID / permit
TWL00195 · CSBC.0128
Outlet location
TQ4470082890 (OS grid reference) · View on Apple Maps
WFD catchment
THAMES MIDDLE (GB530603911402)
2024 spills / hours
7 / 22
Long-term average
4.5 spills a year (monitored since 2020)
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
River Roding(Barking Creek) 0 0.0 down 100% 100%
Gordon Road CSO
Overflow on sewer network
Company site name
Gordon road
EA ID / permit
TWL00198 · TEMP.2637
Outlet location
TQ4357085480 (OS grid reference) · View on Apple Maps
WFD catchment
Seven Kings Water (GB106037028170)
2024 spills / hours
1 / 1.3
Long-term average
0.0 spills a year (monitored since 2020)
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
River Roding 0 0.0 down 100% 100%
Goring Wastewater Treatment Works
Storm tank at sewage works
Sewage works
Goring
Company site name
Goring STW
EA ID / permit
TWL00199 · CTCR.1846
Outlet location
SU6022082930andSU5989082840 (OS grid reference) · View on Apple Maps
WFD catchment
Thames Wallingford to Caversham (GB106039030331)
2024 spills / hours
0 / 0.0
Long-term average
0.1 spills a year (monitored since 2018)
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
River Thames 0 0.0 no change 100%
Gun Wharf CSO
Overflow on sewer network
Company site name
Gun wharf (wapping dock)
EA ID / permit
TWL00426 · CSAB.0548
Outlet location
TQ3502080130 (OS grid reference) · View on Apple Maps
WFD catchment
THAMES MIDDLE (GB530603911402)
2024 spills / hours
1 / 2.0
Long-term average
0.2 spills a year (monitored since 2020)
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
R.Thames ( Tidal ) 0 0.0 down 100% 100%
Hambledon Sewage Treatment Works
Storm tank at sewage works
Sewage works
Hambledon
Company site name
Hambleden STW
EA ID / permit
TWL00209 · CAWM.0192
Outlet location
SU7863084750 (OS grid reference) · View on Apple Maps
WFD catchment
Thames (Reading to Cookham) (GB106039023233)
2024 spills / hours
8 / 105
Long-term average
5.8 spills a year (monitored since 2018)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
River Thames 0 0.0 down 100% 96%
Hammersmith PS CSO
Storm discharge at pumping station
Company site name
Hammersmith Storm SPS
EA ID / permit
TWL00808 · CSAB.0572
Outlet location
TQ2310077990 (OS grid reference) · View on Apple Maps
WFD catchment
THAMES UPPER (GB530603911403)
2024 spills / hours
– / –
Long-term average
0.0 spills a year (monitored since 2024)
Monitor below 90%
Installation set-up/design issue · Resolved - Apr
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
R.Thames ( Tidal ) 0 0.0 73%
Hanger Lane CSO
Overflow on sewer network
Company site name
Hanger lane
EA ID / permit
TWL00213 · EPRAB3796VT
Outlet location
TQ1597078870 (OS grid reference) · View on Apple Maps
WFD catchment
Lower Brent (GB106039023590)
2024 spills / hours
1 / 0.2
Long-term average
0.5 spills a year (monitored since 2020)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
River Brent 0 0.0 down 100% 100%
Henley Wastewater Treatment Works
Storm tank at sewage works
Sewage works
Henley
Company site name
Henley STW
EA ID / permit
TWL00222 · TEMP.2657
Outlet location
SU7605084180 (OS grid reference) · View on Apple Maps
WFD catchment
Thames (Reading to Cookham) (GB106039023233)
2024 spills / hours
86 / 950
Long-term average
12.9 spills a year (monitored since 2018)
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
Fawley Court Stream 0 0.0 down 100% 100%
Holloway Storm Relief CSO
Overflow on sewer network
Company site name
Holloway storm sewer
EA ID / permit
TWL00230 · CSAB.0527
Outlet location
TQ3607080810 (OS grid reference) · View on Apple Maps
WFD catchment
THAMES MIDDLE (GB530603911402)
2024 spills / hours
4 / 6.2
Long-term average
3.8 spills a year (monitored since 2020)
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
R.Thames ( Tidal ) 0 0.0 down 100% 98%
Hungerford WwTW
Storm tank at sewage works
Sewage works
Hungerford
Company site name
Hungerford STW
EA ID / permit
TWL00240 · CSSC.2335
Outlet location
SU3538068200 (OS grid reference) · View on Apple Maps
WFD catchment
Middle Kennet (Hungerford to Newbury) (GB106039023174)
2024 spills / hours
15 / 205
Long-term average
6.3 spills a year (monitored since 2018)
Investigation
Env Act (SODRP) investigation ongoing
Improvement
No improvement action in reporting period
River Kennet 0 0.0 down 100% 100%

Sewage treatment works

Storm tanks and inlet overflows at each Thames Water sewage works. The figures are 2025 spills.

← All water companies · Contains Environment Agency data licensed under the Open Government Licence v3.0. How to read the data.