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
Rusper Sewage Pumping Station Storm discharge at pumping station Company site name Rusper SPS EA ID / permit TWL00356 · EPRQB3796NW Outlet location TQ2017536545 (OS grid reference) · View on Apple Maps WFD catchment Baldhorns Brook (GB106039017470) 2024 spills / hours 28 / 111 Long-term average 41.7 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 85 hours spilling →	Trib of Baldhorns Brook	18	85	down 36%	100%
Crossness WwTW Storm tank at sewage works Sewage works Crossness Company site name Crossness STW EA ID / permit TWL00123 · CSSA.0362 Outlet location TQ4857081130andTQ4850081170 (OS grid reference) · View on Apple Maps WFD catchment THAMES MIDDLE (GB530603911402) 2024 spills / hours 30 / 233 Long-term average 31.9 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 85 hours spilling →	Thames Tidal	13	85	down 57%	100%
Long Reach WwTW Storm tank at sewage works Sewage works Long Reach Company site name Long Reach STW EA ID / permit TWL00277 · CNTD.0067 Outlet location TQ5563076920 (OS grid reference) · View on Apple Maps WFD catchment THAMES MIDDLE (GB530603911402) 2024 spills / hours 38 / 332 Long-term average 35.7 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 84 hours spilling →	Tidal River Thames	10	84	down 74%	100%
Blacknest Sewage Pumping Station Storm discharge at pumping station Company site name Blacknest (Ascot) SPS EA ID / permit TWL00041 · CTCP.0428 Outlet location SU9584068750 (OS grid reference) · View on Apple Maps WFD catchment Virginia Water (GB30642691) 2024 spills / hours 29 / 212 Long-term average 16.3 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 84 hours spilling →	Viginia Water Lake	11	84	down 62%	100%
Warmington STW Inlet overflow at sewage works Sewage works Warmington Company site name Warmington STW EA ID / permit TWL00429 · CSSC.1451 Outlet location SP4150047980 (OS grid reference) · View on Apple Maps WFD catchment Hanwell Brook (GB106039037340) 2024 spills / hours 27 / 217 Long-term average 26.3 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 84 hours spilling →	Hanwell Brook	15	84	down 44%	98%
Honeypot Lane Overflow on sewer network Company site name Honeypot lane EA ID / permit TWL00233 · CANM.0664 Outlet location TQ1884089840 (OS grid reference) · View on Apple Maps WFD catchment Wealdstone Brook (GB106039022940) 2024 spills / hours 43 / 130 Long-term average 39.6 spills a year (monitored since 2019) 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 82 hours spilling →	The Kenton Brook	32	82	down 26%	98%
Canfold Wood Storm discharge at pumping station Company site name Canfold Wood (Ewhurst) SPS EA ID / permit TWL00072 · TEMP.0597 Outlet location TQ0850039700 (OS grid reference) · View on Apple Maps WFD catchment Cranleigh Waters (GB106039017810) 2024 spills / hours 26 / 122 Long-term average 17.4 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 82 hours spilling →	Thornhurst Brook	13	82	down 50%	100%
Kingham Sewage Pumping Station Storm discharge at pumping station Company site name The Mill (Kingham) SPS EA ID / permit TWL00252 · CTCR.1981 Outlet location SP2587023320 (OS grid reference) · View on Apple Maps WFD catchment Cornwell Brook and tributaries (Source to Evenlode) (GB106039037400) 2024 spills / hours 23 / 109 Long-term average 14.2 spills a year (monitored since 2020) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 80 hours spilling →	Trib of Cornwell Brook	17	80	down 26%	100%
Bute Street Xx Overflow on sewer network EA ID / permit TWL00500 · Permit applied for Outlet location TL0917521388 (OS grid reference) · View on Apple Maps WFD catchment Lee (from Luton to Luton Hoo Lakes) (GB106038033391) 2024 spills / hours 15 / 55 Long-term average 9.3 spills a year (monitored since 2023) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 79 hours spilling →		12	79	down 20%	100%
Holybourne SPS Storm discharge at pumping station Company site name Holybourne (Alton) SPS EA ID / permit TWL00232 · CASM.0710 Outlet location SU7351040590 (OS grid reference) · View on Apple Maps WFD catchment North Wey (Alton to Tilford) (GB106039017830) 2024 spills / hours 19 / 290 Long-term average 7.7 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 77 hours spilling →	River Wey	6	77	down 68%	100%
Widford and Wareside WwTW Storm tank at sewage works Sewage works Widford And Wareside Company site name Widford STW EA ID / permit TWL00450 · CLCR.0090 Outlet location TL4167016290 (OS grid reference) · View on Apple Maps WFD catchment Ash (from confluence with Bury Green Brook to Lee) (GB106038033290) 2024 spills / hours 10 / 56 Long-term average 10.6 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 77 hours spilling →	The River Ash	11	77	up 10%	100%
Rotherwick Storm discharge at pumping station Company site name Wedmans Lane (Rotherwick) SPS EA ID / permit TWL00354 · TEMP.1825 Outlet location SU7180056900 (OS grid reference) · View on Apple Maps WFD catchment Whitewater (GB106039017240) 2024 spills / hours 11 / 38 Long-term average 5.8 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 74 hours spilling →	Rotherwick Brook	8	74	down 27%	100%
Brockham Bridge Storm discharge at pumping station Company site name Brockham Bridge XX SPS EA ID / permit TWL00058 · TEMP.0545 Outlet location TQ1960049600 (OS grid reference) · View on Apple Maps WFD catchment Tanners Brook (Holmewood to River Mole confluence at Brockham) (GB106039017570) 2024 spills / hours 15 / 122 Long-term average 7.4 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 72 hours spilling →	River Mole	8	72	down 47%	100%
Culworth Storm tank at sewage works Sewage works Culworth Company site name Culworth STW EA ID / permit TWL00148 · TEMP.2512 Outlet location SP5450046601 (OS grid reference) · View on Apple Maps WFD catchment Cherwell (Ashby Brook to Cropredy) (GB106039037350) 2024 spills / hours 48 / 345 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 71 hours spilling →	Culworth Brook	10	71	down 79%	100%
CSO at Knowle Lane Overflow on sewer network Company site name Knowle lane, cranleigh EA ID / permit TWL00132 · TEMP.2711 Outlet location TQ0568038800 (OS grid reference) · View on Apple Maps WFD catchment Cranleigh Waters (GB106039017810) 2024 spills / hours 22 / 99 Long-term average 13.5 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 70 hours spilling →	Cranleigh Waters/Littlemead	9	70	down 59%	100%
Camberley Storm tank at sewage works Sewage works Camberley Company site name Camberley STW EA ID / permit TWL00070 · TEMP.2455 Outlet location SU8610059300 (OS grid reference) · View on Apple Maps WFD catchment Blackwater (Hawley to Whitewater confluence at Bramshill) (GB106039017290) 2024 spills / hours 25 / 159 Long-term average 19.0 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 69 hours spilling →	Blackwater	7	69	down 72%	100%
Harpenden Storm tank at sewage works Sewage works Harpenden Company site name Harpenden STW EA ID / permit TWL00215 · TEMP.2649 Outlet location TL1509014701 (OS grid reference) · View on Apple Maps WFD catchment Lee (from Luton Hoo Lakes to Hertford) (GB106038033392) 2024 spills / hours 32 / 353 Long-term average 11.0 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 69 hours spilling →	Lee	7	69	down 78%	100%
Winters Brook, Hastingwood Storm discharge at pumping station Company site name Wynters Brook (Hastingwood) SPS EA ID / permit TWL00455 · TEMP.2279 Outlet location TL4890007800 (OS grid reference) · View on Apple Maps WFD catchment Cripsey Brook (GB106037033481) 2024 spills / hours 33 / 327 Long-term average 21.9 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 68 hours spilling →	Shonks Brook	9	68	down 73%	100%
Mulberry Court, Hall Road Overflow on sewer network Company site name Mulberry court, hall road EA ID / permit TWL00307 · TEMP.2801 Outlet location TQ3892085790 (OS grid reference) · View on Apple Maps WFD catchment Lee (Tottenham Locks to Bow Locks/Three Mills Locks) (GB106038077852) 2024 spills / hours 56 / 123 Long-term average 55.9 spills a year (monitored since 2019) 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 68 hours spilling →	Hennikers Ditch	41	68	down 27%	100%
CSO at Capel SPS Storm discharge at pumping station Company site name Capel SPS EA ID / permit TWL00124 · CTCR.1765 Outlet location TQ1808041040 (OS grid reference) · View on Apple Maps WFD catchment Deanoak Brook (GB106039017530) 2024 spills / hours 22 / 89 Long-term average 23.4 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 67 hours spilling →	Deanoak Brook	15	67	down 32%	99%
Stag Lane CSO Overflow on sewer network EA ID / permit TWL00719 · Permit applied for Outlet location TQ2024789610 (OS grid reference) · View on Apple Maps WFD catchment Silk Stream and Edgware Brook (GB106039022970) 2024 spills / hours 13 / 9.5 Long-term average 20.0 spills a year (monitored since 2023) High-spill reason (company) Data collection - EDM non-representative location Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 66 hours spilling →		37	66	up 185%	100%
Longbridge Road Overflow on sewer network Company site name Longbridge road B EA ID / permit TWL00638 · CANM.0919 Outlet location TQ4670085800 (OS grid reference) · View on Apple Maps WFD catchment Mayes Brook (GB106037028171) 2024 spills / hours 35 / 124 Long-term average 53.5 spills a year (monitored since 2020) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 65 hours spilling →	Mayes Brook	28	65	down 20%	100%
Dagnall Wastewater Treatment Works Inlet overflow at sewage works (with treatment) Sewage works Dagnall Company site name Dagnall STW EA ID / permit TWL00149 · CTCU.0375 Outlet location SP9962015530 (OS grid reference) · View on Apple Maps WFD catchment Mid-Chilterns Chalk (GB40601G601200) Treatment Reed bed 2024 spills / hours 53 / 461 Long-term average 47.3 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 64 hours spilling →	Groundwater via Infilt System	17	64	down 68%	100%
Prospect Road CSO, Overflow on sewer network Company site name Prospect road , woodford oxford road EA ID / permit TWL00689 · CANM.0911 Outlet location TQ4145092450 (OS grid reference) · View on Apple Maps WFD catchment Lower Roding (Loughton to Thames) (GB106037028181) 2024 spills / hours 55 / 218 Long-term average 44.0 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 64 hours spilling →	Wells Brook	26	64	down 53%	100%
Ockley Road Storm discharge at pumping station Company site name Ockley Road (Ewhurst) SPS EA ID / permit TWL00318 · TEMP.1627 Outlet location TQ0950040200 (OS grid reference) · View on Apple Maps WFD catchment Cranleigh Waters (GB106039017810) 2024 spills / hours 7 / 17 Long-term average 7.0 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 63 hours spilling →	Cobbler's Brook	9	63	up 29%	92%
Main Road Overflow on sewer network Company site name Main road, sidcup EA ID / permit TWL00644 · T02786 Outlet location TQ4470072200 (OS grid reference) · View on Apple Maps WFD catchment Shuttle (GB106040024210) 2024 spills / hours 55 / 153 Long-term average 32.3 spills a year (monitored since 2023) 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 62 hours spilling →	Freshwater River	33	62	down 40%	100%
Chacombe Wastewater Treatment Works Inlet overflow at sewage works Sewage works Chacombe Company site name Chacombe STW EA ID / permit TWL00078 · CTCR.1766 Outlet location SP4927044170 (OS grid reference) · View on Apple Maps WFD catchment Chacombe Brook (Source to Cherwell) (GB106039037280) 2024 spills / hours 51 / 325 Long-term average 20.9 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 61 hours spilling →	Chacombe Brook	21	61	down 59%	100%
Wealdbridge, North Weald Storm discharge at pumping station Company site name Weald Bridge Road (North Weald) SPS EA ID / permit TWL00435 · TEMP.2197 Outlet location TL5100006400 (OS grid reference) · View on Apple Maps WFD catchment Cripsey Brook (GB106037033481) 2024 spills / hours 19 / 250 Long-term average 17.0 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 60 hours spilling →	Cripsey Brook	8	60	down 58%	98%
Therfield WwTW Inlet overflow at sewage works (with treatment) Sewage works Therfield Company site name Therfield STW EA ID / permit TWL00412 · CATM.3095 Outlet location TL3427034700 (OS grid reference) · View on Apple Maps WFD catchment Rib (upper stretches, above confluence with the Quin) (GB106038040140) Treatment Reed bed 2024 spills / hours 34 / 444 Long-term average 21.6 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 59 hours spilling →	River Rib	5	59	down 85%	100%
Hatfield (Mill Green) Storm tank at sewage works Sewage works Hatfield Company site name Mill Green STW EA ID / permit TWL00218 · TEMP.2653 Outlet location TL2500009701 (OS grid reference) · View on Apple Maps WFD catchment Lee (from Luton Hoo Lakes to Hertford) (GB106038033392) 2024 spills / hours 27 / 224 Long-term average 14.1 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 58 hours spilling →	Lee	6	58	down 78%	100%
Chesham Wastewater Treatment Works Storm tank at sewage works Sewage works Chesham Company site name Chesham STW EA ID / permit TWL00089 · CNTD.0082 Outlet location SU9809099520 (OS grid reference) · View on Apple Maps WFD catchment Chess (GB106039029870) 2024 spills / hours 141 / 2,681 Long-term average 44.6 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 58 hours spilling →	The River Chess	7	58	down 95%	100%
Shotteswell WwTW Storm tank at sewage works Sewage works Shotteswell Company site name Shotteswell STW EA ID / permit TWL00367 · TEMP.2892 Outlet location SP4282045760 (OS grid reference) · View on Apple Maps WFD catchment Hanwell Brook (GB106039037340) 2024 spills / hours 47 / 383 Long-term average 27.0 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 58 hours spilling →	Hanwell Brook	9	58	down 81%	100%
Chalgrove WwTW Storm tank at sewage works Sewage works Chalgrove Company site name Chalgrove STW EA ID / permit TWL00080 · CSSC.2465 Outlet location SU6490098820 (OS grid reference) · View on Apple Maps WFD catchment Haseley Brook (GB106039023780) 2024 spills / hours 147 / 2,854 Long-term average 67.4 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 57 hours spilling →	Warpsgrave Ditch	8	57	down 95%	100%
Deephams Wastewater Treatment Works Storm tank at sewage works Sewage works Deephams Company site name Deephams STW EA ID / permit TWL00152 · CNTD.0072 Outlet location TQ3566093150 (OS grid reference) · View on Apple Maps WFD catchment Pymmes and Salmon Brooks - Deephams STW to Tottenham Locks (GB106038027910) 2024 spills / hours 26 / 231 Long-term average 16.7 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 55 hours spilling →	Salmon Brook	6	55	down 77%	93%
CSO at Moreton-in-Marsh SPS Storm discharge at pumping station Company site name Moreton-in-marsh EA ID / permit TWL00136 · CTCR.2092 Outlet location SP2081032340 (OS grid reference) · View on Apple Maps WFD catchment Evenlode (Source to Four Shires S) and Longborough Stream (GB106039037420) 2024 spills / hours 10 / 38 Long-term average 5.4 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 55 hours spilling →	River Evenlode	9	55	down 10%	100%
Chigwell Road / Langston Road Overflow on sewer network EA ID / permit TWL00514 · Permit applied for Outlet location TQ4428895666 (OS grid reference) · View on Apple Maps WFD catchment Lower Roding (Cripsey Bk to Loughton) (GB106037028182) 2024 spills / hours 15 / 42 Long-term average 13.7 spills a year (monitored since 2023) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 55 hours spilling →		19	55	up 27%	100%
Xx CSO Overflow on sewer network EA ID / permit TWL00575 · Permit applied for Outlet location SU27869634 (OS grid reference) · View on Apple Maps WFD catchment Thames (Leach to Evenlode) (GB106039030333) 2024 spills / hours 70 / 161 Long-term average 51.0 spills a year (monitored since 2023) High-spill reason (company) Performance - SW Infiltration Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 54 hours spilling →		49	54	down 30%	100%
Blunsdon Wastewater Treatment Works Storm tank at sewage works Sewage works Blunsdon Company site name Blunsdon STW EA ID / permit TWL00046 · TEMP.2400 Outlet location SU1513091680 (OS grid reference) · View on Apple Maps WFD catchment Share ditch (GB106039023680) 2024 spills / hours 13 / 156 Long-term average 6.9 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 54 hours spilling →	Tributary of Share Ditch	9	54	down 31%	98%
Charlbury WwTW Storm tank at sewage works Sewage works Charlbury Company site name Charlbury STW EA ID / permit TWL00083 · TEMP.2466 Outlet location SP3530019180 (OS grid reference) · View on Apple Maps WFD catchment Evenlode (Bledington to Glyme confluence) (GB106039029960) 2024 spills / hours 22 / 197 Long-term average 14.9 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 52 hours spilling →	Evenlode	7	52	down 68%	100%
Brentfield Gardens CSO B Overflow on sewer network Company site name Brentfield gardens XX EA ID / permit TWL00053 · TEMP.2413 Outlet location TQ2356087970 (OS grid reference) · View on Apple Maps WFD catchment Dollis Brook and Upper Brent (GB106039022980) 2024 spills / hours 33 / 95 Long-term average 22.0 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 52 hours spilling →	River Brent	26	52	down 21%	100%
Dorking Road Storm discharge at pumping station Company site name Dorking Road (Tadworth) SPS EA ID / permit TWL00158 · TEMP.0844 Outlet location TQ2290054800 (OS grid reference) · View on Apple Maps WFD catchment Wandle (Croydon to Wandsworth) and the Graveney (GB106039023460) 2024 spills / hours 12 / 182 Long-term average 6.5 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 52 hours spilling →	Buckland Brook	10	52	down 17%	100%
Castle Gardens SPS Storm discharge at pumping station Company site name Castle Gardens (Dorking) SPS EA ID / permit TWL00077 · CTCR.0392 Outlet location TQ1910050200 (OS grid reference) · View on Apple Maps WFD catchment Mole - Horley to Dorking (GB106039017625) 2024 spills / hours 12 / 120 Long-term average 5.9 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 48 hours spilling →	Mole	7	48	down 42%	100%
The Willows, North Hinksey Lane Overflow on sewer network Company site name The willows, north hinksey lane EA ID / permit TWL00411 · TEMP.2973 Outlet location SP4953005490 (OS grid reference) · View on Apple Maps WFD catchment Thames (Evenlode to Thame) (GB106039030334) 2024 spills / hours 8 / 62 Long-term average 8.3 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 48 hours spilling →	Seacourt Stream	7	48	down 13%	100%
Tackley SPS Storm discharge at pumping station Company site name Tackley SPS & Storm SPS EA ID / permit TWL00403 · CAWM.0638 Outlet location SP4818020440 (OS grid reference) · View on Apple Maps WFD catchment Cherwell (Nell Bridge to Bletchingdon) (GB106039037431) 2024 spills / hours 30 / 100 Long-term average 5.6 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 47 hours spilling →	Tributary of the Rver Cherwell	4	47	down 87%	100%
Leopold Road, Church Path Overflow on sewer network Company site name Leopold road, church path EA ID / permit TWL00265 · TEMP.2737 Outlet location TQ2149084180 (OS grid reference) · View on Apple Maps WFD catchment Lower Brent (GB106039023590) 2024 spills / hours 42 / 133 Long-term average 34.9 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 →	Mitchell Brook	24	47	down 43%	100%
Deptford Storm Relief CSO Overflow on sewer network Company site name Deptford storm relief EA ID / permit TWL00154 · CSAB.0536 Outlet location TQ3742078070 (OS grid reference) · View on Apple Maps WFD catchment THAMES MIDDLE (GB530603911402) 2024 spills / hours 43 / 178 Long-term average 48.5 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 46 hours spilling →	R.Thames ( Tidal )	3	46	down 93%	100%
Caddington WwTW Storm tank at sewage works (with treatment) Sewage works Caddington Company site name Caddington STW EA ID / permit TWL00068 · CSSC.8551 Outlet location TL0763016920 (OS grid reference) · View on Apple Maps WFD catchment Mid-Chilterns Chalk (GB40601G601200) Treatment Reed bed 2024 spills / hours 32 / 372 Long-term average 9.1 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 46 hours spilling →	Gw via Boreholes & Inf System	5	46	down 84%	100%
Kings Sutton WwTW Storm tank at sewage works Sewage works Kings Sutton Company site name Kings Sutton STW EA ID / permit TWL00255 · CSSC.2339 Outlet location SP5025035620 (OS grid reference) · View on Apple Maps WFD catchment Cherwell (Cropredy to Nell Bridge) (GB106039037310) 2024 spills / hours 36 / 310 Long-term average 12.3 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 45 hours spilling →	Kings Sutton Stream	6	45	down 83%	98%
SWS, Stoke Road, Cobham, Surrey Overflow on sewer network Company site name Stoke road, cobham EA ID / permit TWL00744 · CTCR.2076 Outlet location TQ1128059810 (OS grid reference) · View on Apple Maps WFD catchment Mole - Leatherhead to Hersham (GB106039017623) 2024 spills / hours 14 / 103 Long-term average 7.3 spills a year (monitored since 2023) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 45 hours spilling →	River Mole	6	45	down 57%	96%
Dorton Wastewater Treatment Works Inlet overflow at sewage works Sewage works Dorton Company site name Dorton STW EA ID / permit TWL00160 · CSSC.0465 Outlet location SP6844014200 (OS grid reference) · View on Apple Maps WFD catchment Dorton, Chearsley and Waddesdon Brooks (GB106039030400) 2024 spills / hours 54 / 277 Long-term average 27.5 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 44 hours spilling →	Dorton Brook	12	44	down 78%	93%

Sewage treatment works

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

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