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

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.

Overflow	Discharges to	Spills 2025	Hours 2025	Spills vs 2024	Monitor uptime
Putney Bridge CSO Overflow on sewer network Company site name Putney bridge street EA ID / permit TWL00338 · CSAB.0544 Outlet location TQ2416075640 (OS grid reference) · View on Apple Maps WFD catchment THAMES UPPER (GB530603911403) 2024 spills / hours 127 / 853 Long-term average 50.5 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 16 hours spilling →	R.Thames ( Tidal )	2	16	down 98%	96%
Lytton Road SSO Overflow on sewer network Company site name Lytton road sso EA ID / permit TWL00286 · TEMP.2755 Outlet location TQ2630096400 (OS grid reference) · View on Apple Maps WFD catchment Pymmes Brook upstream Salmon Brook confluence (GB106038027940) 2024 spills / hours 17 / 40 Long-term average 8.6 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 15 hours spilling →	Pymmes Brook	4	15	down 76%	100%
Irongate CSO Overflow on sewer network Company site name Iron gate EA ID / permit TWL00241 · CSAB.0580 Outlet location TQ3371080370 (OS grid reference) · View on Apple Maps WFD catchment THAMES MIDDLE (GB530603911402) 2024 spills / hours 35 / 35 Long-term average 36.9 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 15 hours spilling →	R.Thames ( Tidal )	28	15	down 20%	100%
East Lane CSO 1 Overflow on sewer network EA ID / permit TWL00557 · Permit applied for Outlet location TQ1867586841 (OS grid reference) · View on Apple Maps WFD catchment Wealdstone Brook (GB106039022940) 2024 spills / hours 3 / 9.5 Long-term average 4.0 spills a year (monitored since 2023) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 15 hours spilling →		5	15	up 67%	100%
Grampian Gardens CSO Overflow on sewer network EA ID / permit TWL00590 · Unpermitted Outlet location TQ2419087245 (OS grid reference) · View on Apple Maps WFD catchment Dollis Brook and Upper Brent (GB106039022980) 2024 spills / hours 3 / 4.4 Long-term average 10.5 spills a year (monitored since 2024) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 15 hours spilling →		18	15	up 500%	100%
Cricklewood Broadway Overflow on sewer network EA ID / permit TWL00533 · Permit applied for Outlet location TQ2295485712 (OS grid reference) · View on Apple Maps WFD catchment Lower Brent (GB106039023590) 2024 spills / hours 12 / 22 Long-term average 8.3 spills a year (monitored since 2023) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 15 hours spilling →		4	15	down 67%	100%
Edgware Road Overflow on sewer network EA ID / permit TWL00561 · Unpermitted Outlet location TQ2184787898 (OS grid reference) · View on Apple Maps WFD catchment Silk Stream and Edgware Brook (GB106039022970) 2024 spills / hours 2 / 13 Long-term average 2.0 spills a year (monitored since 2023) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 14 hours spilling →		4	14	up 100%	94%
Francis Road Spill Overflow on sewer network EA ID / permit TWL00583 · Permit applied for Outlet location TQ1654488775 (OS grid reference) · View on Apple Maps WFD catchment Wealdstone Brook (GB106039022940) 2024 spills / hours 21 / 32 Long-term average 11.0 spills a year (monitored since 2023) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 14 hours spilling →		11	14	down 48%	100%
CSO at Hannington Overflow on sewer network Company site name Hannington EA ID / permit TWL00130 · TEMP.2675 Outlet location SU1772093470 (OS grid reference) · View on Apple Maps WFD catchment Bydemill Brook (Source to Thames) (GB106039023710) 2024 spills / hours 21 / 69 Long-term average 12.8 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 14 hours spilling →	Bydemill Ditch	8	14	down 62%	100%
Beddington Storm tank at sewage works Sewage works Beddington Company site name Beddington STW EA ID / permit TWL00030 · TEMP.2381 Outlet location TQ2830066800 (OS grid reference) · View on Apple Maps WFD catchment Wandle (Croydon to Wandsworth) and the Graveney (GB106039023460) 2024 spills / hours 10 / 48 Long-term average 13.6 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 14 hours spilling →	Beddington effluent carrier/Wa	5	14	down 50%	100%
Frogmore Sr (Bell Lane Creek) CSO Overflow on sewer network Company site name Frogmore storm EA ID / permit TWL00032 · TEMP.2599 Outlet location TQ2549074980 (OS grid reference) · View on Apple Maps WFD catchment Wandle (Croydon to Wandsworth) and the Graveney (GB106039023460) 2024 spills / hours 31 / 79 Long-term average 22.7 spills a year (monitored since 2020) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 14 hours spilling →	Bell Lane Creek (Estuarine)	2	14	down 94%	100%
Savoy Street CSO Overflow on sewer network Company site name Savoy street EA ID / permit TWL00360 · CSAB.0532 Outlet location TQ3066080630 (OS grid reference) · View on Apple Maps WFD catchment THAMES MIDDLE (GB530603911402) 2024 spills / hours 5 / 1.9 Long-term average 10.2 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 13 hours spilling →	R.Thames ( Tidal )	6	13	up 20%	93%
Crooked Billet SPS Storm discharge at pumping station Company site name Crooked Billet (Hook) SPS & Storm SPS EA ID / permit TWL00121 · CATM.3173 Outlet location SU7376054780 (OS grid reference) · View on Apple Maps WFD catchment Whitewater (GB106039017240) 2024 spills / hours 19 / 58 Long-term average 11.0 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 13 hours spilling →	River Whitewater	7	13	down 63%	100%
Manor Drive Storm Tanks Overflow on sewer network Company site name Manor drive stormwater tanks EA ID / permit TWL00288 · CTCR.0519 Outlet location TQ2108063580 (OS grid reference) · View on Apple Maps WFD catchment Hogsmill (GB106039017440) 2024 spills / hours 9 / 16 Long-term average 9.1 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 13 hours spilling →	Hogsmill	4	13	down 56%	96%
Highworth Eastrop CSO (Gwa site) Overflow on sewer network EA ID / permit TWL00226 · Unpermitted Outlet location SU2084592713 (OS grid reference) · View on Apple Maps WFD catchment Shrivenham Corallian (GB40602G600600) 2024 spills / hours 29 / 53 Long-term average 23.3 spills a year (monitored since 2019) Monitor below 90% Comms failure / issue · Resolved - Jun Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 12 hours spilling →		9	12	down 69%	90%
Spooks Hill Overflow on sewer network Company site name Spooks hill, north holmwood EA ID / permit TWL00381 · CTCR.1922 Outlet location TQ1685047500 (OS grid reference) · View on Apple Maps WFD catchment Tanners Brook (Holmewood to River Mole confluence at Brockham) (GB106039017570) 2024 spills / hours 12 / 36 Long-term average 6.6 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 12 hours spilling →	Tanners Brook (Bents Brook)	3	12	down 75%	97%
Elmcroft Avenue, Overflow on sewer network Company site name ELMCROFT AVENUE F TQ4189121G CSO EA ID / permit TWL00792 · CANM.0910 Outlet location TQ4140089300 (OS grid reference) · View on Apple Maps WFD catchment Lower Roding (Loughton to Thames) (GB106037028181) 2024 spills / hours 21 / 35 Long-term average 11.3 spills a year (monitored since 2023) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 12 hours spilling →	The River Roding	13	12	down 38%	100%
Huckers Lane Storm discharge at pumping station Company site name Selbourne SPS EA ID / permit TWL00239 · TEMP.1200 Outlet location SU7440033900 (OS grid reference) · View on Apple Maps WFD catchment Oakhanger Stream (GB106039017710) 2024 spills / hours 4 / 2.3 Long-term average 15.4 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 12 hours spilling →	Oakhanger Stream	2	12	down 50%	99%
Acton PS Sr CSO Storm discharge at pumping station Company site name Acton Ealing SPS EA ID / permit TWL00005 · TEMP.0312 Outlet location TQ2198078020 (OS grid reference) · View on Apple Maps WFD catchment THAMES UPPER (GB530603911403) 2024 spills / hours 22 / 136 Long-term average 18.0 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 11 hours spilling →	Thames ( Tidal )	1	11	down 95%	100%
CSO at Western Way Overflow on sewer network Company site name Western way EA ID / permit TWL00145 · TEMP.3036 Outlet location TQ2536095080 (OS grid reference) · View on Apple Maps WFD catchment Dollis Brook and Upper Brent (GB106039022980) 2024 spills / hours 13 / 25 Long-term average 11.7 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 11 hours spilling →	Dollis Brook	3	11	down 77%	99%
Taylors Crescent, Cranleigh Overflow on sewer network Company site name Taylors crescent, cranleigh EA ID / permit TWL00406 · TEMP.2966 Outlet location TQ0670039240 (OS grid reference) · View on Apple Maps WFD catchment Cranleigh Waters (GB106039017810) 2024 spills / hours 5 / 24 Long-term average 5.9 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 11 hours spilling →	Cranleigh Waters	3	11	down 40%	100%
Standon WwTW Storm tank at sewage works Sewage works Standon Company site name Standon STW EA ID / permit TWL00386 · CSSC.2365 Outlet location TL3972021700 (OS grid reference) · View on Apple Maps WFD catchment Rib (from confluence with Quin to Lee Navigation) (GB106038033360) 2024 spills / hours 17 / 101 Long-term average 4.3 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 11 hours spilling →	Rib	2	11	down 88%	99%
Auckland Road Pumping Station Tanks Storm discharge at pumping station Company site name Auckland Road (Leyton) Storm SPS EA ID / permit TWL00019 · CSBC.0085 Outlet location TQ3751086390 (OS grid reference) · View on Apple Maps WFD catchment Lee (Tottenham Locks to Bow Locks/Three Mills Locks) (GB106038077852) 2024 spills / hours 14 / 73 Long-term average 12.0 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 10 hours spilling →	Trib of the Dagenham Brook	2	10	down 86%	100%
Little Marlow STW Storm tank at sewage works Sewage works Little Marlow Company site name Little Marlow STW EA ID / permit TWL00270 · CNTD.0058 Outlet location SU8771086960 (OS grid reference) · View on Apple Maps WFD catchment Thames (Reading to Cookham) (GB106039023233) 2024 spills / hours 9 / 60 Long-term average 8.6 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 10 hours spilling →	River Thames	2	10	down 78%	99%
Boyne Avenue, Hendon Overflow on sewer network EA ID / permit TWL00484 · Permit applied for Outlet location TQ2403689156 (OS grid reference) · View on Apple Maps WFD catchment Dollis Brook and Upper Brent (GB106039022980) 2024 spills / hours 14 / 24 Long-term average 12.0 spills a year (monitored since 2023) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 10 hours spilling →		6	10	down 57%	100%
Friday Street, Henley Storm discharge at pumping station Company site name Friday Street (Henley) SPS EA ID / permit TWL00191 · TEMP.1003 Outlet location SU7630082700 (OS grid reference) · View on Apple Maps WFD catchment Thames (Reading to Cookham) (GB106039023233) 2024 spills / hours 17 / 53 Long-term average 7.5 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 9.8 hours spilling →	Thames	4	9.8	down 76%	98%
Chapmore End Inlet overflow at sewage works Sewage works Chapmore End Company site name Chapmore End STW EA ID / permit TWL00082 · TEMP.2465 Outlet location TL3320016711 (OS grid reference) · View on Apple Maps WFD catchment Rib (from confluence with Quin to Lee Navigation) (GB106038033360) 2024 spills / hours 17 / 66 Long-term average 26.8 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 9.8 hours spilling →	Rib	7	9.8	down 59%	100%
Elvetham Close Storm discharge at pumping station Company site name Elvetham Road (Fleet) SPS EA ID / permit TWL00171 · TEMP.0917 Outlet location SU8040055100 (OS grid reference) · View on Apple Maps WFD catchment Basingstoke Canal (GB70610019) 2024 spills / hours 9 / 24 Long-term average 4.4 spills a year (monitored since 2019) Monitor below 90% Comms failure / issue · Resolved - Aug Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 9.5 hours spilling →	Basingstoke Canal	7	9.5	down 22%	78%
Lots Road PS CSO Storm discharge at pumping station Company site name Lots Road (Chelsea) Storm SPS EA ID / permit TWL00116 · CSAB.0573 Outlet location TQ2659077090 (OS grid reference) · View on Apple Maps WFD catchment THAMES UPPER (GB530603911403) 2024 spills / hours 21 / 72 Long-term average 16.2 spills a year (monitored since 2020) Monitor below 90% Installation set-up/design issue · Resolved - Nov Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 9.3 hours spilling →	R.Thames ( Tidal )	1	9.3	down 95%	49%
Hammersmith PS CSO Storm discharge at pumping station Company site name Hammersmith Storm SPS EA ID / permit TWL00210 · CSAB.0572 Outlet location TQ2310077990 (OS grid reference) · View on Apple Maps WFD catchment THAMES UPPER (GB530603911403) 2024 spills / hours 27 / 130 Long-term average 19.5 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 9.3 hours spilling →	R.Thames ( Tidal )	2	9.3	down 93%	100%
Trumpers Way, W7 Storm discharge at pumping station Company site name Trumpers Way (Hanwell) SPS EA ID / permit TWL00417 · TEMP.2125 Outlet location TQ1520079300 (OS grid reference) · View on Apple Maps WFD catchment Lower Brent (GB106039023590) 2024 spills / hours 32 / 60 Long-term average 22.1 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 9.3 hours spilling →	River Brent	7	9.3	down 78%	92%
Marsworth Storm discharge at pumping station Company site name Marsworth SPS EA ID / permit TWL00296 · TEMP.2766 Outlet location SP9160015201 (OS grid reference) · View on Apple Maps WFD catchment Thame upstream of Aylesbury (GB106039030410) 2024 spills / hours 19 / 115 Long-term average 6.1 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 9.3 hours spilling →	Thame	3	9.3	down 84%	100%
Beer Lane CSO Overflow on sewer network Company site name Beer lane EA ID / permit TWL00282 · CSAB.0559 Outlet location TQ3330080540 (OS grid reference) · View on Apple Maps WFD catchment THAMES MIDDLE (GB530603911402) 2024 spills / hours 35 / 32 Long-term average 28.5 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 9.2 hours spilling →	R.Thames ( Tidal )	24	9.2	down 31%	100%
Brook Way CSO Overflow on sewer network Company site name Brook way, chigwell EA ID / permit TWL00059 · TEMP.2449 Outlet location TQ4339093190 (OS grid reference) · View on Apple Maps WFD catchment Lower Roding (Loughton to Thames) (GB106037028181) 2024 spills / hours 18 / 31 Long-term average 17.3 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 8.8 hours spilling →	Chigwell Brook	7	8.8	down 61%	100%
Worcester Crescent CSO Overflow on sewer network Company site name Worcester crescent EA ID / permit TWL00463 · EPRAB3890DU Outlet location TQ4192092190 (OS grid reference) · View on Apple Maps WFD catchment Lower Roding (Loughton to Thames) (GB106037028181) 2024 spills / hours – / – Long-term average 38.8 spills a year (monitored since 2019) Monitor below 90% Comms failure / issue · Resolved - Mar Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 8.8 hours spilling →	The River Roding	10	8.8		86%
Churt SPS Storm discharge at pumping station Company site name Churt SPS EA ID / permit TWL00101 · CASM.0403 Outlet location SU8529038080 (OS grid reference) · View on Apple Maps WFD catchment South Wey (River Slea confluence to Tilford) (GB106039017780) Bathing water Frensham Great Pond 2024 spills / hours 6 / 9.1 Long-term average 5.4 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 8.3 hours spilling →	Whitmoor Vale Stream	4	8.3	down 33%	100%
Aldershot CSO Overflow on sewer network EA ID / permit TWL00472 · Permit applied for Outlet location SU88405050 (OS grid reference) · View on Apple Maps WFD catchment Blackwater (Aldershot to Cove Brook confluence at Hawley) (GB106039017180) 2024 spills / hours 6 / 28 Long-term average 12.3 spills a year (monitored since 2023) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 8.3 hours spilling →		2	8.3	down 67%	100%
Falcon Brook PS CSO Storm discharge at pumping station Company site name Falconsbrook (Battersea) Storm SPS EA ID / permit TWL00179 · CSAB.0557 Outlet location TQ2648076020 (OS grid reference) · View on Apple Maps WFD catchment THAMES UPPER (GB530603911403) 2024 spills / hours 39 / 101 Long-term average 34.8 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 8.1 hours spilling →	R.Thames ( Tidal )	3	8.1	down 92%	100%
Fulmer Drive Combined Sewer Overflw Overflow on sewer network Company site name FULMER DRIVE CSO EA ID / permit TWL00799 · TEMP.2609 Outlet location TQ0016086510 (OS grid reference) · View on Apple Maps WFD catchment Alderbourne (GB106039023080) 2024 spills / hours 30 / 149 Long-term average 17.7 spills a year (monitored since 2023) Monitor below 90% Comms failure / issue · Resolved - Feb Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 8.0 hours spilling →	Alderbourne	5	8.0	down 83%	90%
CSO at Daintry Road Overflow on sewer network Company site name Daintry close EA ID / permit TWL00126 · CANM.0233 Outlet location TQ1633089220 (OS grid reference) · View on Apple Maps WFD catchment Wealdstone Brook (GB106039022940) 2024 spills / hours 14 / 25 Long-term average 21.4 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 7.8 hours spilling →	Wealdstone Brook	6	7.8	down 57%	100%
Priory Lane, Mortlake CSO Overflow on sewer network Company site name Priory lane storm, mortlake EA ID / permit TWL00334 · TEMP.2837 Outlet location TQ2150075520 (OS grid reference) · View on Apple Maps WFD catchment Beverley Brook (Motspur Park to Thames) and Pyl Brook at West Barnes (GB106039022850) 2024 spills / hours 9 / 17 Long-term average 10.3 spills a year (monitored since 2020) Monitor below 90% Comms failure / issue · Resolved - Jul Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 7.8 hours spilling →	Beverley Brook	3	7.8	down 67%	88%
Chisledon storm tanks Overflow on sewer network EA ID / permit TWL00790 · Permit applied for Outlet location SU1855380475 (OS grid reference) · View on Apple Maps WFD catchment Cole (source to Lenta Brook) (GB106039022890) 2024 spills / hours 18 / 156 Long-term average 14.3 spills a year (monitored since 2023) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 7.5 hours spilling →		2	7.5	down 89%	100%
Brixton and Clapham Sr CSO Overflow on sewer network Company site name Brixton and Clapham Storm Relief EA ID / permit TWL00810 · CSAB.0554 Outlet location TQ3023078090 (OS grid reference) · View on Apple Maps WFD catchment Thames Middle (GB530603911402) 2024 spills / hours – / – Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 7.4 hours spilling →	River Thames (Tidal)	2	7.4		100%
Riverside STW Storm tank at sewage works Sewage works Riverside Company site name Riverside STW EA ID / permit TWL00350 · CSSA.0364 Outlet location TQ5152081920 (OS grid reference) · View on Apple Maps WFD catchment THAMES MIDDLE (GB530603911402) 2024 spills / hours 15 / 105 Long-term average 39.4 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 7.0 hours spilling →	The Rainham Creek	1	7.0	down 93%	100%
Streatham Vale Storm Relief Overflow on sewer network Company site name Streatham vale storm relief EA ID / permit TWL00396 · TEMP.2922 Outlet location TQ2942070070 (OS grid reference) · View on Apple Maps WFD catchment Wandle (Croydon to Wandsworth) and the Graveney (GB106039023460) 2024 spills / hours 12 / 15 Long-term average 11.7 spills a year (monitored since 2020) Monitor below 90% Comms failure / issue · Resolved - Jul Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 7.0 hours spilling →	River Graveney	7	7.0	down 42%	74%
Midgham Wastewater Treatment Works Storm tank at sewage works Sewage works Midgham Company site name Midgham STW EA ID / permit TWL00301 · CTCR.1531 Outlet location SU5560067400 (OS grid reference) · View on Apple Maps WFD catchment Kennet and Avon Canal, Copse Lock to Reading (GB70610180) 2024 spills / hours 3 / 17 Long-term average 4.3 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 6.3 hours spilling →	Kennet & Avon Canal	1	6.3	down 67%	99%
Prospect Road CSO, A Overflow on sewer network Company site name Prospect road , woodford Monkhams lane EA ID / permit TWL00336 · CANM.0911 Outlet location TQ4145092450 (OS grid reference) · View on Apple Maps WFD catchment Lower Roding (Loughton to Thames) (GB106037028181) 2024 spills / hours 11 / 16 Long-term average 27.1 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 6.3 hours spilling →	Wells Brook	6	6.3	down 45%	100%
Stanford in the Vale STW Storm tank at sewage works (with treatment) Sewage works Stanford In The Vale Company site name Stanford in the Vale STW EA ID / permit TWL00387 · CSSC.2317 Outlet location SU3442092910 (OS grid reference) · View on Apple Maps WFD catchment Ock (to Cherbury Brook) (GB106039023400) Treatment Reed bed 2024 spills / hours 0 / 0.0 Long-term average 2.3 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 6.3 hours spilling →	The River Ock	3	6.3	up from 0	100%
Littlemore Low Level Storm discharge at pumping station Company site name Heyford Hill Lane (Littlemore) SPS EA ID / permit TWL00273 · TEMP.1358 Outlet location SP5250002900 (OS grid reference) · View on Apple Maps WFD catchment Thames (Evenlode to Thame) (GB106039030334) 2024 spills / hours 26 / 171 Long-term average 6.9 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 6.1 hours spilling →	Thames	1	6.1	down 96%	100%
CSO at High Road Overflow on sewer network Company site name High road, woodford EA ID / permit TWL00131 · TEMP.2681 Outlet location TQ4149089290 (OS grid reference) · View on Apple Maps WFD catchment Lower Roding (Loughton to Thames) (GB106037028181) 2024 spills / hours 14 / 19 Long-term average 16.1 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 6.0 hours spilling →	River Roding	9	6.0	down 36%	100%

Sewage treatment works

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

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