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
Park Street - Xx (lower level weir) Overflow on sewer network EA ID / permit TWL00679 · Permit applied for Outlet location TL0989220738 (OS grid reference) · View on Apple Maps WFD catchment Lee (from Luton to Luton Hoo Lakes) (GB106038033391) 2024 spills / hours 33 / 20 Long-term average 22.3 spills a year (monitored since 2023) Monitor below 90% Comms failure / issue · Resolved - Aug Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 5.7 hours spilling →		20	5.7	down 39%	87%
Ruislip Road East Overflow on sewer network EA ID / permit TWL00704 · Unpermitted Outlet location TQ1563682350 (OS grid reference) · View on Apple Maps WFD catchment Lower Brent (GB106039023590) 2024 spills / hours 2 / 4.6 Long-term average 4.3 spills a year (monitored since 2023) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 5.6 hours spilling →		4	5.6	up 100%	100%
Elmcroft Avenue, Overflow on sewer network Company site name ELMCROFT AVENUE 115 TQ40899104 CSO EA ID / permit TWL00794 · CANM.0910 Outlet location TQ4140089300 (OS grid reference) · View on Apple Maps WFD catchment Lower Roding (Loughton to Thames) (GB106037028181) 2024 spills / hours 22 / 18 Long-term average 16.3 spills a year (monitored since 2023) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 5.5 hours spilling →	The River Roding	13	5.5	down 41%	100%
Princes Avenue CSO Overflow on sewer network Company site name Princes avenue EA ID / permit TWL00332 · EPRAB3799WV Outlet location TQ4192092190 (OS grid reference) · View on Apple Maps WFD catchment Lower Roding (Loughton to Thames) (GB106037028181) 2024 spills / hours 13 / 19 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 5.5 hours spilling →	The River Roding	7	5.5	down 46%	100%
Falloden Court & Brookland Rise Overflow on sewer network EA ID / permit TWL00574 · Permit applied for Outlet location TQ2538889154 (OS grid reference) · View on Apple Maps WFD catchment Dollis Brook and Upper Brent (GB106039022980) 2024 spills / hours 9 / 8.5 Long-term average 4.7 spills a year (monitored since 2023) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 5.4 hours spilling →		3	5.4	down 67%	100%
Buntingford WwTW Storm tank at sewage works Sewage works Buntingford Company site name Buntingford STW EA ID / permit TWL00062 · CATM.3092 Outlet location TL3639028670 (OS grid reference) · View on Apple Maps WFD catchment Rib (upper stretches, above confluence with the Quin) (GB106038040140) 2024 spills / hours 31 / 237 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 5.3 hours spilling →	The River Rib	3	5.3	down 90%	100%
Commonside Storm discharge at pumping station Company site name Commonside (Leatherhead) SPS EA ID / permit TWL00111 · TEMP.0730 Outlet location TQ1330056200 (OS grid reference) · View on Apple Maps WFD catchment Downside Ditches and Bookham Brook (GB106039017600) 2024 spills / hours 13 / 37 Long-term average 4.3 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 5.3 hours spilling →	Bookham Brook	2	5.3	down 85%	100%
Swains Road Storm discharge at pumping station Company site name Swains Road (Tadley) SPS EA ID / permit TWL00401 · TEMP.2032 Outlet location SU5990061500 (OS grid reference) · View on Apple Maps WFD catchment Silchester Brook (GB106039017190) 2024 spills / hours 2 / 5.5 Long-term average 3.9 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 5.3 hours spilling →	Silchester Brook	1	5.3	down 50%	97%
Fairfield Avenue Xx Overflow on sewer network EA ID / permit TWL00571 · Permit applied for Outlet location TQ2309187690 (OS grid reference) · View on Apple Maps WFD catchment Dollis Brook and Upper Brent (GB106039022980) 2024 spills / hours 10 / 5.4 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 5.1 hours spilling →		11	5.1	up 10%	100%
River Lane Pumping Station Storm discharge at pumping station Company site name River Lane (Leatherhead) SPS EA ID / permit TWL00349 · CTCR.1644 Outlet location TQ1470057100 (OS grid reference) · View on Apple Maps WFD catchment Mole - Leatherhead to Hersham (GB106039017623) 2024 spills / hours 6 / 11 Long-term average 3.8 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 5.0 hours spilling →	Mole	2	5.0	down 67%	100%
Church Road/Brent Lodge Park (Bunny Park) Overflow on sewer network EA ID / permit TWL00521 · Permit applied for Outlet location TQ1472380454 (OS grid reference) · View on Apple Maps WFD catchment Lower Brent (GB106039023590) 2024 spills / hours 2 / 12 Long-term average 1.0 spills a year (monitored since 2023) Monitor below 90% Comms failure / issue · Resolved - Jun Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 4.9 hours spilling →		1	4.9	down 50%	56%
Smith Street Main Line CSO Overflow on sewer network Company site name Smith street EA ID / permit TWL00372 · CSAB.0578 Outlet location TQ2810077790 (OS grid reference) · View on Apple Maps WFD catchment THAMES MIDDLE (GB530603911402) 2024 spills / hours 16 / 13 Long-term average 13.0 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 4.8 hours spilling →	R.Thames ( Tidal )	6	4.8	down 63%	95%
Longbridge Road Overflow on sewer network Company site name Longbridge road A EA ID / permit TWL00278 · CANM.0919 Outlet location TQ4670085800 (OS grid reference) · View on Apple Maps WFD catchment Mayes Brook (GB106037028171) 2024 spills / hours 14 / 25 Long-term average 33.8 spills a year (monitored since 2020) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 4.8 hours spilling →	Mayes Brook	4	4.8	down 71%	100%
Neasden Station Overflow on sewer network EA ID / permit TWL00660 · Permit applied for Outlet location TQ2142985180 (OS grid reference) · View on Apple Maps WFD catchment Lower Brent (GB106039023590) 2024 spills / hours 12 / 16 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 4.6 hours spilling →		4	4.6	down 67%	100%
Wood Street CSO Overflow on sewer network Company site name Wood street EA ID / permit TWL00460 · CSAB.0564 Outlet location TQ3029079220 (OS grid reference) · View on Apple Maps WFD catchment THAMES MIDDLE (GB530603911402) 2024 spills / hours 9 / 23 Long-term average 8.2 spills a year (monitored since 2020) 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 4.6 hours spilling →	R.Thames ( Tidal )	4	4.6	down 56%	79%
Earl PS CSO Storm discharge at pumping station Company site name Earl (Bermondsey) SPS EA ID / permit TWL00163 · CSAB.0533 Outlet location TQ3679078970 (OS grid reference) · View on Apple Maps WFD catchment THAMES MIDDLE (GB530603911402) 2024 spills / hours 23 / 98 Long-term average 16.5 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 4.5 hours spilling →	R.Thames ( Tidal )	2	4.5	down 91%	100%
Lower Cherwell St Wps, Banbury Storm discharge at pumping station Company site name Cherwell Street (Banbury) SPS & SSP EA ID / permit TWL00281 · CATM.3189 Outlet location SP4610040190 (OS grid reference) · View on Apple Maps WFD catchment Cherwell (Cropredy to Nell Bridge) (GB106039037310) 2024 spills / hours 14 / 57 Long-term average 4.7 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 4.5 hours spilling →	River Cherwell	4	4.5	down 71%	100%
South Norwood CSO Overflow on sewer network Company site name South norwood EA ID / permit TWL00379 · CGLR.0019 Outlet location TQ3517068550 (OS grid reference) · View on Apple Maps WFD catchment Pool River (GB106039023250) 2024 spills / hours 12 / 25 Long-term average 10.1 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 4.5 hours spilling →	Chaffinch Brook	4	4.5	down 67%	95%
Old Palace Lane Overflow on sewer network EA ID / permit TWL00672 · Permit applied for Outlet location TQ1730874822 (OS grid reference) · View on Apple Maps WFD catchment THAMES UPPER (GB530603911403) 2024 spills / hours 24 / 30 Long-term average 10.0 spills a year (monitored since 2023) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 4.5 hours spilling →		4	4.5	down 83%	100%
Ranelagh CSO Overflow on sewer network Company site name Sloane street, raneleigh gardens EA ID / permit TWL00780 · CSAB.0577 Outlet location TQ2828077820 (OS grid reference) · View on Apple Maps WFD catchment THAMES MIDDLE (GB530603911402) 2024 spills / hours 0 / 0.0 Long-term average 0.5 spills a year (monitored since 2024) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 4.4 hours spilling →	R.Thames ( Tidal )	1	4.4	up from 0	100%
CSO at Duntshill Road Overflow on sewer network Company site name Duntshill road EA ID / permit TWL00127 · TEMP.2555 Outlet location TQ2580073070 (OS grid reference) · View on Apple Maps WFD catchment Wandle (Croydon to Wandsworth) and the Graveney (GB106039023460) 2024 spills / hours 1 / 2.3 Long-term average 1.0 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 4.3 hours spilling →	River Wandle	1	4.3	no change	100%
King'S Scholars Pond CSO Overflow on sewer network Company site name Kings scholars pond EA ID / permit TWL00254 · CSAB.0561 Outlet location TQ2987078060 (OS grid reference) · View on Apple Maps WFD catchment THAMES MIDDLE (GB530603911402) 2024 spills / hours 9 / 19 Long-term average 9.6 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 4.2 hours spilling →	R.Thames ( Tidal )	4	4.2	down 56%	100%
Forest Hill Storm tank at sewage works Sewage works Forest Hill Company site name Forest Hill STW EA ID / permit TWL00188 · TEMP.2597 Outlet location SP5910008101 (OS grid reference) · View on Apple Maps WFD catchment Holton Brook and tributaries (GB106039030360) 2024 spills / hours 5 / 25 Long-term average 4.8 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 4.0 hours spilling →	Polecat End Ditch	3	4.0	down 40%	100%
Fleet Main CSO Overflow on sewer network Company site name Fleet main line sewer EA ID / permit TWL00322 · CSAB.0541 Outlet location TQ3148080770 (OS grid reference) · View on Apple Maps WFD catchment THAMES MIDDLE (GB530603911402) 2024 spills / hours 0 / 0.0 Long-term average 1.0 spills a year (monitored since 2024) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 4.0 hours spilling →	R.Thames ( Tidal )	2	4.0	up from 0	100%
Deptford Creek CSO Overflow on sewer network Company site name Deptford creek storm EA ID / permit TWL00153 · TEMP.2540 Outlet location TQ3741077080 (OS grid reference) · View on Apple Maps WFD catchment THAMES MIDDLE (GB530603911402) 2024 spills / hours 9 / 12 Long-term average 8.8 spills a year (monitored since 2020) Monitor below 90% Comms failure / issue · Resolved - Sep Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 3.9 hours spilling →	Ravensbourne/Deptford Creek	2	3.9	down 78%	81%
Elmcroft Avenue, Overflow on sewer network Company site name ELMCROFT AVENUE/NIGHTINGALE LANE TQ40886902 CSO EA ID / permit TWL00796 · CANM.0910 Outlet location TQ4140089300 (OS grid reference) · View on Apple Maps WFD catchment Lower Roding (Loughton to Thames) (GB106037028181) 2024 spills / hours 12 / 7.9 Long-term average 11.7 spills a year (monitored since 2023) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 3.9 hours spilling →	The River Roding	14	3.9	up 17%	96%
Stansted Airport Storm discharge at pumping station Company site name Stansted Airport SPS EA ID / permit TWL00722 · TEMP.1976 Outlet location TL5490021800 (OS grid reference) · View on Apple Maps WFD catchment Pincey Brook (GB106038033380) 2024 spills / hours 2 / 0.1 Long-term average 1.5 spills a year (monitored since 2023) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 3.9 hours spilling →	Pincey Brook	1	3.9	down 50%	99%
Home Park Road Overflow on sewer network EA ID / permit TWL00608 · Permit applied for Outlet location TQ2491472339 (OS grid reference) · View on Apple Maps WFD catchment Wandle (Croydon to Wandsworth) and the Graveney (GB106039023460) 2024 spills / hours 6 / 8.8 Long-term average 5.0 spills a year (monitored since 2023) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 3.8 hours spilling →		3	3.8	down 50%	100%
Outside 115 Wentworth Road Overflow on sewer network Company site name XX wentworth road EA ID / permit TWL00320 · CANM.1219 Outlet location TQ2465088130 (OS grid reference) · View on Apple Maps WFD catchment Dollis Brook and Upper Brent (GB106039022980) 2024 spills / hours 6 / 10 Long-term average 4.9 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 3.8 hours spilling →	Decoy Brook	2	3.8	down 67%	100%
London Bridge CSO Overflow on sewer network Company site name London bridge EA ID / permit TWL00274 · TEMP.2743 Outlet location TQ3286080600 (OS grid reference) · View on Apple Maps WFD catchment THAMES MIDDLE (GB530603911402) 2024 spills / hours 9 / 17 Long-term average 6.5 spills a year (monitored since 2020) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 3.7 hours spilling →	Tidal Thames	7	3.7	down 22%	100%
Horseferry Road CSO Overflow on sewer network Company site name Horseferry road EA ID / permit TWL00237 · CSAB.0563 Outlet location TQ3027079010 (OS grid reference) · View on Apple Maps WFD catchment THAMES MIDDLE (GB530603911402) 2024 spills / hours 17 / 46 Long-term average 17.5 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 3.7 hours spilling →	R.Thames ( Tidal )	4	3.7	down 76%	100%
Highfield Rd Jct With Brookside Rd Overflow on sewer network Company site name Highfield road jct with brookside road EA ID / permit TWL00225 · CANM.1220 Outlet location TQ2434088350 (OS grid reference) · View on Apple Maps WFD catchment Dollis Brook and Upper Brent (GB106039022980) 2024 spills / hours 1 / 0.5 Long-term average 0.6 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 3.5 hours spilling →	Decoy Brook	2	3.5	up 100%	100%
Stamford Brook Sr CSO Overflow on sewer network Company site name Stamford brook EA ID / permit TWL00384 · CSAB.0534 Outlet location TQ2270078310 (OS grid reference) · View on Apple Maps WFD catchment THAMES UPPER (GB530603911403) 2024 spills / hours 4 / 4.8 Long-term average 6.0 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 3.3 hours spilling →	R.Thames ( Tidal )	1	3.3	down 75%	100%
Hatfield Broad Oak Cage End Storm discharge at pumping station Company site name Cage End (Hatfield Broadoak) SPS EA ID / permit TWL00069 · TEMP.1114 Outlet location TL5460016300 (OS grid reference) · View on Apple Maps WFD catchment Pincey Brook (GB106038033380) 2024 spills / hours 15 / 94 Long-term average 9.3 spills a year (monitored since 2019) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 3.0 hours spilling →	Pinsey Brook	2	3.0	down 87%	100%
Elmcroft Avenue, Overflow on sewer network Company site name ELMCROFT AVENUE TQ40883902 CSO EA ID / permit TWL00797 · CANM.0910 Outlet location TQ4140089300 (OS grid reference) · View on Apple Maps WFD catchment Lower Roding (Loughton to Thames) (GB106037028181) 2024 spills / hours 11 / 3.5 Long-term average 9.0 spills a year (monitored since 2023) Monitor below 90% Comms failure / issue · Resolved - Sep Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 2.8 hours spilling →	The River Roding	10	2.8	down 9%	89%
Shad Pumping Station CSO Storm discharge at pumping station Company site name Shad Thames (Bermondsey) Storm SPS EA ID / permit TWL00364 · CSAB.0555 Outlet location TQ3392080000 (OS grid reference) · View on Apple Maps WFD catchment THAMES MIDDLE (GB530603911402) 2024 spills / hours 12 / 30 Long-term average 17.5 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 2.8 hours spilling →	R.Thames ( Tidal )	2	2.8	down 83%	100%
Earlswood Common, S of Pendleton Ro Overflow on sewer network Company site name Earlswood common, s of pendleton road EA ID / permit TWL00164 · TEMP.2575 Outlet location TQ2694048631 (OS grid reference) · View on Apple Maps WFD catchment Mole - Horley to Dorking (GB106039017625) 2024 spills / hours 0 / 0.0 Long-term average 4.6 spills a year (monitored since 2018) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 2.8 hours spilling →	Redhill Brook	3	2.8	up from 0	95%
Alicia Avenue CSO Overflow on sewer network EA ID / permit TWL00474 · Permit applied for Outlet location TQ1725489033 (OS grid reference) · View on Apple Maps WFD catchment Wealdstone Brook (GB106039022940) 2024 spills / hours 5 / 9.1 Long-term average 3.3 spills a year (monitored since 2023) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 2.7 hours spilling →		1	2.7	down 80%	98%
Abbeydale Road Overflow on sewer network EA ID / permit TWL00468 · Permit applied for Outlet location TQ1911483508 (OS grid reference) · View on Apple Maps WFD catchment Lower Brent (GB106039023590) 2024 spills / hours 2 / 4.4 Long-term average 1.0 spills a year (monitored since 2023) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 2.6 hours spilling →		1	2.6	down 50%	100%
CSO at Portsmouth/Uxbridge Road Overflow on sewer network Company site name Portsmouth road, uxbridge road EA ID / permit TWL00140 · TEMP.2843 Outlet location TQ1767068010 (OS grid reference) · View on Apple Maps WFD catchment Thames (Egham to Teddington) (GB106039023232) 2024 spills / hours 6 / 6.8 Long-term average 4.7 spills a year (monitored since 2019) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 2.5 hours spilling →	River Thames	2	2.5	down 67%	100%
Bushey Court CSO Overflow on sewer network Company site name Bushey court, raynes park EA ID / permit TWL00066 · TEMP.2429 Outlet location TQ2182069890 (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 3 / 16 Long-term average 1.9 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 2.3 hours spilling →	Beverley Brook	1	2.3	down 67%	100%
CSO at Redbridge Lane West Overflow on sewer network Company site name Redbridge lane west, wanstead EA ID / permit TWL00540 · CANM.0976 Outlet location TQ4140088200 (OS grid reference) · View on Apple Maps WFD catchment Lower Roding (Loughton to Thames) (GB106037028181) 2024 spills / hours 21 / 27 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 2.3 hours spilling →	To River Roding	4	2.3	down 81%	100%
Nutter Lane / Preston Drive CSO Overflow on sewer network Company site name Nutter lane / preston drive, wanstead EA ID / permit TWL00316 · CEVR.0138 Outlet location TQ4162088710 (OS grid reference) · View on Apple Maps WFD catchment Lower Roding (Loughton to Thames) (GB106037028181) 2024 spills / hours 11 / 20 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 2.0 hours spilling →	Roding	3	2.0	down 73%	100%
CSO at St James'S Road Overflow on sewer network Company site name St james's road EA ID / permit TWL00142 · TEMP.2938 Outlet location TQ1801068960 (OS grid reference) · View on Apple Maps WFD catchment Hogsmill (GB106039017440) 2024 spills / hours 5 / 5.0 Long-term average 2.6 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 1.9 hours spilling →	Hogsmill River	2	1.9	down 60%	100%
North End Road CSO Overflow on sewer network EA ID / permit TWL00666 · Permit applied for Outlet location TQ1945486178 (OS grid reference) · View on Apple Maps WFD catchment Wealdstone Brook (GB106039022940) 2024 spills / hours 2 / 1.5 Long-term average 1.0 spills a year (monitored since 2023) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 1.8 hours spilling →		1	1.8	down 50%	100%
Frogmore Sr (Wandle) CSO Overflow on sewer network Company site name Bell lane creek EA ID / permit TWL00192 · TEMP.2438 Outlet location TQ2559074550 (OS grid reference) · View on Apple Maps WFD catchment Wandle (Croydon to Wandsworth) and the Graveney (GB106039023460) 2024 spills / hours 49 / 172 Long-term average 40.8 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 1.7 hours spilling →	Wandle	1	1.7	down 98%	99%
CSO at Longley Road Overflow on sewer network Company site name Longley road XX, tooting high street EA ID / permit TWL00133 · TEMP.2747 Outlet location TQ2711070890 (OS grid reference) · View on Apple Maps WFD catchment Wandle (Croydon to Wandsworth) and the Graveney (GB106039023460) 2024 spills / hours 1 / 3.0 Long-term average 2.0 spills a year (monitored since 2018) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 1.5 hours spilling →	River Graveney	2	1.5	up 100%	98%
Epsom Storm Tanks Overflow on sewer network Company site name Epsom storm tanks EA ID / permit TWL00566 · CTCP.0585 Outlet location TQ2108062160 (OS grid reference) · View on Apple Maps WFD catchment Hogsmill (GB106039017440) 2024 spills / hours 2 / 3.3 Long-term average 3.3 spills a year (monitored since 2023) Investigation Env Act (SODRP) investigation ongoing Improvement No improvement action in reporting period Volume & pollution Estimate from 1.5 hours spilling →	Green Lanes Stream	2	1.5	no change	100%
Northumberland Street CSO Overflow on sewer network Company site name Northumberland street EA ID / permit TWL00315 · CSAB.0531 Outlet location TQ3042080270 (OS grid reference) · View on Apple Maps WFD catchment THAMES MIDDLE (GB530603911402) 2024 spills / hours 16 / 38 Long-term average 14.0 spills a year (monitored since 2020) Investigation No investigation activity in reporting period Improvement No improvement action in reporting period Volume & pollution Estimate from 1.5 hours spilling →	R.Thames ( Tidal )	1	1.5	down 94%	100%
Bishop'S Stortford Main SPS Storm discharge at pumping station Company site name Bishop stortford main SPS EA ID / permit TWL00040 · CTCR.1919 Outlet location TL4944020110 (OS grid reference) · View on Apple Maps WFD catchment Stort and Navigation, B Stortford to Harlow (GB106038033281) 2024 spills / hours 12 / 101 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 1.4 hours spilling →	Stort Navigation	1	1.4	down 92%	100%

Sewage treatment works

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

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