Storm overflow register · Yorkshire Water

Permit Applied For sewage works: storm overflow spills 2025

Permit Applied For sewage treatment works, run by Yorkshire Water, has 14 monitored storm overflows discharging to Permit applied for. In 2025 they recorded 568 spills totalling 3,810 hours, against 829 spills and 7,225 hours in 2024. By hours spilling, it ranks 1 of 283 Yorkshire Water works, where 1 spilled longest.

Every spill in 2025

Each blue mark is one spill, placed by when it started and sized by how long it lasted. Hover over a mark for the date and duration.

JanFebMarAprMayJunJulAugSepOctNovDecPermit applied for5 spills, 17.8 h, 1 Jan to 2 Jan6 spills, 39.8 h, 5 Jan to 7 Jan4 spills, 5 h, 23 Jan to 24 Jan12 spills, 78.3 h, 26 Jan to 30 Jan5 Feb 2025 07:00 GMT, 15 min2 spills, 1.3 h, 20 Feb to 20 Feb3 spills, 2.5 h, 23 Feb to 23 Feb26 Feb 2025 09:15 GMT, 45 min7 Mar 2025 00:15 GMT, 15 min3 spills, 0.8 h, 12 Mar to 13 Mar2 spills, 1 h, 22 Mar to 22 Mar2 spills, 1.3 h, 22 Apr to 22 Apr3 spills, 2.5 h, 24 May to 24 May2 spills, 1.3 h, 26 May to 27 May2 spills, 1.3 h, 29 May to 29 May3 Jun 2025 08:00 GMT, 45 min6 Jun 2025 07:00 GMT, 75 min9 Jun 2025 22:30 GMT, 45 min2 spills, 0.5 h, 2 Jul to 2 Jul5 spills, 2.3 h, 15 Jul to 15 Jul4 spills, 3.3 h, 19 Jul to 19 Jul2 spills, 1.5 h, 20 Jul to 20 Jul4 Aug 2025 06:15 GMT, 30 min27 Aug 2025 15:00 GMT, 30 min2 spills, 0.5 h, 28 Aug to 28 Aug30 Aug 2025 21:45 GMT, 15 min3 Sep 2025 04:15 GMT, 15 min4 Sep 2025 15:15 GMT, 45 min13 Sep 2025 16:00 GMT, 15 min7 spills, 6.8 h, 14 Sep to 16 Sep5 spills, 12.3 h, 20 Sep to 21 Sep5 spills, 10.8 h, 2 Oct to 3 Oct19 Oct 2025 17:00 GMT, 8.5 h3 spills, 2 h, 23 Oct to 23 Oct2 spills, 0.5 h, 24 Oct to 25 Oct28 Oct 2025 18:45 GMT, 15 min31 Oct 2025 01:15 GMT, 15 min5 Nov 2025 07:30 GMT, 60 min7 spills, 5.5 h, 10 Nov to 12 Nov49 spills, 278 h, 12 Nov to 27 Nov28 Nov 2025 13:00 GMT, 75 min8 spills, 92.3 h, 29 Nov to 3 Dec2 spills, 2 h, 4 Dec to 5 Dec9 spills, 105.3 h, 5 Dec to 11 Dec12 spills, 83 h, 15 Dec to 19 Dec3 spills, 8.3 h, 21 Dec to 22 Dec13 spills, 5.8 h, 23 Dec to 25 Dec4 spills, 1 h, 26 Dec to 27 Dec28 Dec 2025 10:00 GMT, 15 minPermit applied for1 Jan 2025 00:00 GMT, 19 h5 Jan 2025 13:00 GMT, 121.3 h24 Jan 2025 07:15 GMT, 3 h27 Jan 2025 02:30 GMT, 61 h17 Feb 2025 16:30 GMT, 60 min20 Feb 2025 15:45 GMT, 69.3 h5 spills, 29.3 h, 26 Feb to 27 Feb15 Apr 2025 06:30 GMT, 8.3 h2 spills, 4.3 h, 12 May to 13 May21 May 2025 05:15 GMT, 4.5 h3 spills, 62.8 h, 24 May to 27 May10 Jun 2025 00:00 GMT, 30 min2 spills, 1 h, 22 Jun to 22 Jun2 Jul 2025 04:15 GMT, 60 min2 spills, 3.3 h, 15 Jul to 15 Jul19 Jul 2025 15:30 GMT, 3.5 h20 Jul 2025 14:30 GMT, 5 h1 Aug 2025 09:15 GMT, 30 min18 Aug 2025 19:45 GMT, 5.3 h27 Aug 2025 15:15 GMT, 7.3 h28 Aug 2025 17:15 GMT, 15 min3 spills, 7.3 h, 15 Sep to 15 Sep20 Sep 2025 11:45 GMT, 15.3 h2 spills, 7.8 h, 3 Oct to 3 Oct2 spills, 4 h, 19 Oct to 20 Oct23 Oct 2025 03:15 GMT, 3.5 h31 Oct 2025 17:30 GMT, 105 min4 spills, 37.8 h, 10 Nov to 13 Nov14 Nov 2025 19:45 GMT, 7.8 h2 spills, 23.3 h, 18 Nov to 19 Nov7 spills, 21 h, 23 Nov to 24 Nov28 Nov 2025 13:45 GMT, 60 min29 Nov 2025 16:45 GMT, 64.5 h6 spills, 34.3 h, 4 Dec to 7 Dec9 Dec 2025 05:00 GMT, 19 h15 Dec 2025 01:45 GMT, 28 h2 spills, 27.3 h, 17 Dec to 19 DecPermit applied for1 Jan 2025 02:45 GMT, 10 h5 spills, 49 h, 5 Jan to 7 Jan24 Jan 2025 03:30 GMT, 2 h2 spills, 20.8 h, 26 Jan to 27 Jan20 Feb 2025 15:15 GMT, 3.5 h2 spills, 2.5 h, 23 Feb to 24 Feb24 May 2025 03:15 GMT, 60 min2 spills, 2.3 h, 15 Jul to 15 Jul19 Jul 2025 15:15 GMT, 2.8 h4 Sep 2025 15:45 GMT, 45 min15 Sep 2025 13:00 GMT, 15 min3 spills, 9.3 h, 20 Sep to 21 Sep2 spills, 2.8 h, 3 Oct to 3 Oct31 Oct 2025 18:00 GMT, 30 min11 Nov 2025 22:00 GMT, 2.3 h14 Nov 2025 21:00 GMT, 2.3 h3 spills, 57 h, 23 Nov to 26 Nov28 Nov 2025 13:30 GMT, 45 min15 spills, 68.5 h, 29 Nov to 3 Dec4 Dec 2025 21:30 GMT, 90 min12 spills, 89 h, 5 Dec to 11 Dec2 spills, 43.3 h, 15 Dec to 17 Dec7 spills, 49.5 h, 17 Dec to 20 DecPermit applied for53 spills, 4.6 h, 1 Jan to 2 Jan130 spills, 44.6 h, 5 Jan to 8 Jan137 spills, 18.2 h, 27 Jan to 28 Jan46 spills, 17.2 h, 20 Sep to 21 Sep25 spills, 5 h, 3 Oct to 4 Oct45 spills, 7.5 h, 23 Oct to 25 Oct23 spills, 4.3 h, 10 Nov to 11 Nov325 spills, 56.4 h, 12 Nov to 17 Nov341 spills, 119.4 h, 18 Nov to 25 Nov160 spills, 45 h, 29 Nov to 2 Dec205 spills, 23.4 h, 4 Dec to 7 Dec56 spills, 12.9 h, 9 Dec to 10 Dec43 spills, 10.6 h, 15 Dec to 16 Dec135 spills, 15.1 h, 18 Dec to 20 DecPermit applied for5 spills, 52.5 h, 1 Jan to 3 Jan5 spills, 12.8 h, 6 Jan to 6 Jan7 spills, 13.3 h, 13 Jan to 14 Jan16 Jan 2025 09:15 GMT, 15 min2 spills, 6.5 h, 23 Jan to 24 Jan15 spills, 30.5 h, 26 Jan to 28 Jan4 Feb 2025 13:45 GMT, 30 min10 Feb 2025 23:00 GMT, 15 min3 spills, 2.3 h, 20 Feb to 20 Feb7 spills, 4 h, 21 Feb to 21 Feb11 spills, 21 h, 23 Feb to 24 Feb26 Feb 2025 07:30 GMT, 15 min2 spills, 2 h, 22 Mar to 22 Mar2 spills, 0.5 h, 28 Mar to 28 Mar16 Apr 2025 04:45 GMT, 30 min3 spills, 3.8 h, 26 May to 27 May4 spills, 2.3 h, 29 May to 30 May2 spills, 3 h, 3 Jun to 3 Jun3 spills, 0.8 h, 4 Jun to 5 Jun3 spills, 3 h, 6 Jun to 7 Jun3 spills, 1.5 h, 9 Jun to 10 Jun13 Jun 2025 23:45 GMT, 30 min22 Jun 2025 17:00 GMT, 60 min2 Jul 2025 01:30 GMT, 30 min6 spills, 2.8 h, 6 Jul to 6 Jul4 spills, 3 h, 15 Jul to 15 Jul19 Jul 2025 16:45 GMT, 15 min2 spills, 1.8 h, 20 Jul to 20 Jul21 Jul 2025 13:00 GMT, 45 min2 spills, 0.8 h, 4 Aug to 4 Aug5 Aug 2025 08:45 GMT, 15 min3 Sep 2025 10:00 GMT, 15 min7 Sep 2025 14:00 GMT, 15 min6 spills, 1.8 h, 10 Sep to 11 Sep3 spills, 0.8 h, 12 Sep to 13 Sep10 spills, 4.3 h, 15 Sep to 16 Sep6 spills, 13.3 h, 20 Sep to 21 Sep10 spills, 9.5 h, 2 Oct to 4 Oct7 spills, 3 h, 19 Oct to 20 Oct26 Oct 2025 20:00 GMT, 15 min27 Oct 2025 23:45 GMT, 30 min2 spills, 0.5 h, 29 Oct to 29 Oct8 spills, 5 h, 3 Nov to 5 Nov7 Nov 2025 18:15 GMT, 15 min4 spills, 9 h, 11 Nov to 12 Nov11 spills, 56.8 h, 12 Nov to 15 Nov18 Nov 2025 12:15 GMT, 15 min7 spills, 3 h, 23 Nov to 24 Nov4 spills, 1.8 h, 28 Nov to 28 Nov11 spills, 8.3 h, 1 Dec to 2 Dec4 spills, 6 h, 5 Dec to 6 Dec2 spills, 0.5 h, 7 Dec to 7 Dec6 spills, 15.8 h, 9 Dec to 10 Dec15 Dec 2025 17:45 GMT, 15 min3 spills, 2 h, 17 Dec to 17 Dec18 Dec 2025 19:00 GMT, 15 min3 spills, 2.3 h, 21 Dec to 22 DecPermit applied for1 Jan 2025 00:00 GMT, 59.5 h4 spills, 2.8 h, 24 Jan to 24 Jan2 spills, 4.3 h, 26 Jan to 27 Jan20 Feb 2025 13:15 GMT, 60 min2 spills, 1 h, 21 Feb to 21 Feb2 spills, 2.5 h, 23 Feb to 24 Feb22 Mar 2025 17:15 GMT, 45 min22 Jun 2025 17:00 GMT, 15 min2 Jul 2025 01:30 GMT, 30 min2 spills, 0.8 h, 6 Jul to 6 Jul2 spills, 1.8 h, 15 Jul to 15 Jul20 Jul 2025 15:00 GMT, 15 min5 Aug 2025 08:45 GMT, 15 min11 Sep 2025 09:45 GMT, 30 min12 Sep 2025 20:30 GMT, 30 min5 spills, 2 h, 15 Sep to 15 Sep6 spills, 10.3 h, 20 Sep to 21 Sep3 spills, 3.3 h, 3 Oct to 3 Oct4 Oct 2025 17:15 GMT, 15 min11 Nov 2025 20:00 GMT, 90 min12 spills, 108.3 h, 12 Nov to 17 Nov18 Nov 2025 12:00 GMT, 45 min3 spills, 1.8 h, 23 Nov to 23 Nov2 spills, 1.3 h, 28 Nov to 28 Nov5 spills, 3.8 h, 1 Dec to 1 Dec13 spills, 8.3 h, 5 Dec to 8 Dec5 spills, 51 h, 9 Dec to 11 Dec4 spills, 1.8 h, 17 Dec to 17 Dec2 spills, 1.5 h, 21 Dec to 22 DecPermit applied for3 spills, 9.8 h, 5 Jan to 6 Jan24 Jan 2025 04:15 GMT, 15 min27 Jan 2025 03:45 GMT, 60 min2 spills, 0.5 h, 24 May to 24 May3 spills, 1.3 h, 2 Jun to 2 Jun5 Jun 2025 16:30 GMT, 15 min2 spills, 1 h, 2 Jul to 2 Jul15 Jul 2025 19:00 GMT, 2 h3 spills, 1.5 h, 31 Jul to 1 Aug7 Aug 2025 13:00 GMT, 15 min4 Sep 2025 14:15 GMT, 2.3 h11 Sep 2025 12:00 GMT, 15 min2 spills, 0.5 h, 15 Sep to 15 Sep17 Sep 2025 12:00 GMT, 30 min7 spills, 25.3 h, 20 Sep to 22 Sep3 spills, 4.3 h, 3 Oct to 3 Oct24 Oct 2025 23:00 GMT, 4 h28 Oct 2025 01:00 GMT, 30 min10 Nov 2025 16:30 GMT, 90 min11 Nov 2025 22:15 GMT, 15 min8 spills, 35 h, 12 Nov to 15 Nov18 Nov 2025 19:30 GMT, 30 min19 Nov 2025 16:15 GMT, 60 min7 spills, 89.8 h, 20 Nov to 25 Nov28 Nov 2025 13:15 GMT, 45 min4 spills, 45.8 h, 29 Nov to 1 Dec5 Dec 2025 19:15 GMT, 5.8 h9 Dec 2025 12:30 GMT, 15 min2 spills, 3.8 h, 15 Dec to 15 Dec2 spills, 0.5 h, 17 Dec to 18 DecPermit applied for2 spills, 23.8 h, 5 Jan to 6 Jan2 spills, 1.8 h, 24 Jan to 24 Jan2 spills, 15.5 h, 26 Jan to 27 Jan3 spills, 2.8 h, 28 Jan to 28 Jan4 spills, 2.5 h, 6 Feb to 7 Feb6 spills, 3.8 h, 10 Feb to 11 Feb2 spills, 1 h, 15 Jul to 15 Jul1 Sep 2025 13:00 GMT, 30 min2 spills, 25.8 h, 20 Sep to 21 Sep7 spills, 36 h, 3 Oct to 6 Oct20 Oct 2025 16:45 GMT, 45 min23 Oct 2025 09:00 GMT, 60 min24 Oct 2025 23:00 GMT, 9.8 h2 spills, 0.5 h, 13 Nov to 13 Nov4 spills, 4.5 h, 18 Nov to 19 Nov4 spills, 26.3 h, 23 Nov to 24 Nov29 Nov 2025 18:15 GMT, 15.5 h4 spills, 10.3 h, 1 Dec to 2 Dec5 Dec 2025 20:30 GMT, 12 h2 spills, 12 h, 9 Dec to 10 Dec2 spills, 0.8 h, 11 Dec to 11 DecPermit applied for1 Jan 2025 02:15 GMT, 9 h27 Jan 2025 02:15 GMT, 21.3 h20 Feb 2025 13:30 GMT, 2.8 h2 spills, 14.5 h, 21 Feb to 22 Feb3 spills, 39.8 h, 23 Feb to 25 Feb15 Jul 2025 17:30 GMT, 2 h2 spills, 7.5 h, 20 Sep to 21 Sep2 spills, 2 h, 3 Oct to 3 Oct2 spills, 19.5 h, 12 Nov to 13 Nov4 spills, 8.8 h, 14 Nov to 15 Nov2 spills, 2.3 h, 5 Dec to 6 Dec2 spills, 24.5 h, 9 Dec to 10 Dec3 spills, 8 h, 15 Dec to 16 DecPermit applied for29 Jan 2025 11:15 GMT, 15 min2 spills, 3.5 h, 9 Feb to 10 Feb20 Feb 2025 14:00 GMT, 30 min6 Jun 2025 07:15 GMT, 105 min6 Jul 2025 16:30 GMT, 45 min15 Jul 2025 18:15 GMT, 90 min2 spills, 1.5 h, 19 Jul to 19 Jul2 spills, 8.3 h, 20 Sep to 21 Sep2 spills, 1 h, 3 Oct to 3 Oct11 Nov 2025 21:00 GMT, 75 min6 spills, 42.3 h, 12 Nov to 15 Nov2 spills, 6 h, 29 Nov to 30 Nov2 spills, 3 h, 1 Dec to 1 Dec5 Dec 2025 20:00 GMT, 4.5 h5 spills, 28.3 h, 9 Dec to 10 Dec15 Dec 2025 18:30 GMT, 3.8 hPermit applied for6 Jan 2025 06:30 GMT, 27 h2 spills, 35.3 h, 27 Jan to 28 Jan2 spills, 16.5 h, 20 Feb to 21 Feb15 Jul 2025 18:30 GMT, 45 min19 Jul 2025 16:00 GMT, 60 min4 Sep 2025 16:00 GMT, 30 min4 spills, 2.3 h, 20 Sep to 20 Sep1 Dec 2025 21:00 GMT, 75 min2 spills, 12.8 h, 15 Dec to 15 Dec18 Dec 2025 15:30 GMT, 105 minPermit applied for3 spills, 5.5 h, 1 Jan to 1 Jan3 spills, 20.5 h, 5 Jan to 6 Jan27 Jan 2025 02:00 GMT, 90 min22 Mar 2025 15:15 GMT, 60 min22 Apr 2025 11:00 GMT, 15 min5 Jun 2025 18:30 GMT, 15 min22 Jun 2025 20:30 GMT, 15 min2 Jul 2025 03:15 GMT, 45 min6 Jul 2025 07:00 GMT, 15 min3 spills, 0.8 h, 20 Jul to 20 Jul21 Jul 2025 13:30 GMT, 75 min13 Sep 2025 16:45 GMT, 15 min17 Sep 2025 04:00 GMT, 15 min8 spills, 3.8 h, 20 Sep to 21 Sep2 spills, 0.8 h, 19 Oct to 19 Oct23 Oct 2025 00:45 GMT, 15 min31 Oct 2025 17:15 GMT, 15 min3 spills, 6.3 h, 14 Nov to 14 Nov18 Nov 2025 15:15 GMT, 15 min2 spills, 0.5 h, 23 Nov to 23 Nov5 spills, 2.3 h, 29 Nov to 29 Nov4 Dec 2025 16:00 GMT, 45 min6 Dec 2025 13:45 GMT, 15 min2 spills, 0.5 h, 9 Dec to 9 Dec12 Dec 2025 10:30 GMT, 15 min3 spills, 2.3 h, 17 Dec to 18 DecPermit applied for17 Jul 2025 12:00 GMT, 45 min2 spills, 27.3 h, 21 Jul to 22 Jul31 Jul 2025 08:45 GMT, 15 min3 spills, 2.5 h, 20 Sep to 21 Sep19 Nov 2025 01:45 GMT, 15 min3 spills, 10.5 h, 29 Nov to 30 NovPermit applied for19 Jul 2025 16:00 GMT, 15 min13 Sep 2025 21:00 GMT, 15 min10 Nov 2025 16:30 GMT, 15 min

Hours spilling by month, 2025

05001,0001,500Jan 2025: 851 hours spillingJanFeb 2025: 227 hours spillingFebMar 2025: 6.3 hours spillingMarApr 2025: 10 hours spillingAprMay 2025: 84 hours spillingMayJun 2025: 18 hours spillingJunJul 2025: 81 hours spillingJulAug 2025: 17 hours spillingAugSep 2025: 184 hours spillingSepOct 2025: 133 hours spillingOctNov 2025: 1,225 hours spillingNovDec 2025: 973 hours spillingDec
Hours, measured by the event duration monitor.

Longest single spills

Started (GMT)OverflowDuration
5 Jan 2025, 13:00Permit applied for5.1 days
13 Nov 2025, 11:15Permit applied for3.7 days
20 Feb 2025, 15:45Permit applied for2.9 days
20 Nov 2025, 12:30Permit applied for2.8 days
29 Nov 2025, 16:45Permit applied for2.7 days

Estimated 2025 spill volume and pollution

Estimate, not a measurement. Monitors record how long an overflow spills, not how much. This calculator back-calculates a spill rate from the size of the works, using the Environment Agency's permit formulae, and multiplies it by published storm-sewage concentrations. How it works.

This works serves fewer than 2,000 people, or was not matched to a UWWTD report, so its size is not published. The population equivalent above is a placeholder of 1,000. Enter the population served if you know it.

Volume, central estimate65,282 m³range 26,003 - 163,894 m³
In litres65.3 millionrange 26.0 million - 163.9 million L
Olympic swimming pools26at 2,500 m³ each
Organic load, as people's raw sewage97,923person-days of untreated BOD

Assumed spill rate while spilling: 1.9 - 11.9 L/s (central 4.8 L/s), from a dry-weather flow of 1.9 L/s.

Pollutant releasedLowCentralHighConcentration used (low / typical / high)
BOD₅ (organic load) 1,040 kg5,875 kg32,779 kg 40 / 90 / 200 mg/L
Low/high: Europe range, Ellis & Jenkins 2005; typical: UK, Ellis & Jenkins 2005 (both via botturi)
Suspended solids 2,730 kg27,745 kg118,167 kg 105 / 425 / 721 mg/L
Low/high: Europe range; typical: UK, Ellis & Jenkins 2005 (via botturi)
Ammonium-N 49 kg411 kg1,524 kg 1.9 / 6.3 / 9.3 mg/L
Low: Germany, Brombach 2005; typical/high: Paris range 3.3-9.3 midpoint and top, Gasperi 2012 (via botturi); no UK value found
Total phosphorus 31 kg170 kg885 kg 1.2 / 2.6 / 5.4 mg/L
Low/high: Paris, Gasperi 2012; typical: Slovakia (via botturi). UK figure of 10 mg/L treated as an outlier
E. coli 2.6 trillion organisms65.3 trillion organisms1.6 × 10¹⁵ organisms 10,000 / 100,000 / 1.0 million per 100 mL
Median range at CSO and retention-tank outlets, Stott et al. 2018 (via botturi); typical = log midpoint

Low combines the low spill rate with low concentrations, and high combines high with high, so the true figure is very likely inside the range. Long spills become more diluted as they go on, so the central figure tends to overstate the load of long events. The calculator does not estimate the effect on the receiving water, which depends on river flow or tide at the time of the spill.

Permit applied for

Inlet overflow at sewage works · discharges to Permit applied for

Spills 2025
99 (792 hours) · down 40% on 2024
Spills 2024
166 (1,275 hours)
Long-term average
100.3 spills a year (monitored since 2020)
Monitor uptime
100% of the year
High-spill reason (company)
Not asset maintenance - hydraulic capacity
Investigation
UWWTR investigation ongoing, Operational investigation completed
Improvement
No improvement action in reporting period
WFD catchment
Holbeck from Source to Marrs Beck (GB104027068420)
Outlet location
SE6220078800 (OS grid reference) · View on Apple Maps
EA ID / permit
YWS00911 · Permit applied for · company name: OSWALDKIRK/STW

Permit applied for

Storm tank at sewage works · discharges to Permit applied for

Spills 2025
69 (714 hours) · down 51% on 2024
Spills 2024
142 (2,624 hours)
Long-term average
80.2 spills a year (monitored since 2020)
Monitor uptime
100% of the year
High-spill reason (company)
Performance - SW Infiltration
Investigation
UWWTR investigation ongoing, Operational investigation completed
Improvement
Operational improvement completed
WFD catchment
Derwent from River Rye to Kirkham (GB104027068313)
Outlet location
SE7580065400 (OS grid reference) · View on Apple Maps
EA ID / permit
YWS00913 · Permit applied for · company name: WESTOW/STW

Permit applied for

Inlet overflow at sewage works · discharges to Permit applied for

Spills 2025
45 (421 hours) · down 34% on 2024
Spills 2024
68 (643 hours)
Long-term average
55.0 spills a year (monitored since 2020)
Monitor uptime
100% of the year
High-spill reason (company)
Performance - SW Infiltration
Investigation
UWWTR investigation ongoing, Operational investigation completed
Improvement
Operational improvement completed
WFD catchment
Seven from Catter Beck to River Rye (GB104027068440)
Outlet location
SE7400078200 (OS grid reference) · View on Apple Maps
EA ID / permit
YWS00812 · Permit applied for · company name: BRAWBY/STW

Permit applied for

Storm tank at sewage works (with treatment) · discharges to Permit applied for

Spills 2025
45 (384 hours) · down 31% on 2024
Spills 2024
65 (513 hours)
Long-term average
54.3 spills a year (monitored since 2022)
Monitor uptime
100% of the year
High-spill reason (company)
Not asset maintenance - hydraulic capacity
Investigation
UWWTR investigation ongoing, Operational investigation completed
Improvement
No improvement action in reporting period
Treatment
UV (Ultraviolet)
Bathing water
Scarborough South Bay
WFD catchment
Yorkshire North (GB650401500004)
Outlet location
TA0470191640 (OS grid reference) · View on Apple Maps
EA ID / permit
YWS02243 · Permit applied for · company name: SCARBOROUGH/STW/STORM TREATMENT

Permit applied for

Inlet overflow at sewage works · discharges to Permit applied for

Spills 2025
88 (318 hours) · down 32% on 2024
Spills 2024
129 (721 hours)
Long-term average
109.2 spills a year (monitored since 2020)
Monitor uptime
100% of the year
High-spill reason (company)
Not asset maintenance - hydraulic capacity
Investigation
UWWTR investigation ongoing, Operational investigation ongoing
Improvement
No improvement action in reporting period
WFD catchment
Bishopdale Bk from Source to Walden Beck (GB104027069360)
Outlet location
SE0130087500 (OS grid reference) · View on Apple Maps
EA ID / permit
YWS00037 · Permit applied for · company name: WEST BURTON/STW

Permit applied for

Inlet overflow at sewage works · discharges to Permit applied for

Spills 2025
46 (272 hours) · down 22% on 2024
Spills 2024
59 (385 hours)
Long-term average
73.5 spills a year (monitored since 2020)
Monitor uptime
100% of the year
High-spill reason (company)
Not asset maintenance - hydraulic capacity
Investigation
UWWTR investigation ongoing, Operational investigation completed
Improvement
No improvement action in reporting period
WFD catchment
Bishopdale Bk from Source to Walden Beck (GB104027069360)
Outlet location
SE0030086700 (OS grid reference) · View on Apple Maps
EA ID / permit
YWS00046 · Permit applied for · company name: THORALBY/STW

Permit applied for

Inlet overflow at sewage works · discharges to Permit applied for

Spills 2025
44 (240 hours) · up 22% on 2024
Spills 2024
36 (114 hours)
Long-term average
35.2 spills a year (monitored since 2020)
Monitor uptime
100% of the year
High-spill reason (company)
Not asset maintenance - hydraulic capacity
Investigation
UWWTR investigation ongoing, Operational investigation completed
Improvement
No improvement action in reporting period
WFD catchment
Sandsend Beck/Mickley Bk from Source to North Sea (GB104027068720)
Outlet location
NZ8070012800 (OS grid reference) · View on Apple Maps
EA ID / permit
YWS00045 · Permit applied for · company name: MICKLEBY/STW

Permit applied for

Inlet overflow at sewage works · discharges to Permit applied for

Spills 2025
34 (207 hours) · down 23% on 2024
Spills 2024
44 (297 hours)
Long-term average
28.8 spills a year (monitored since 2020)
Monitor uptime
100% of the year
High-spill reason (company)
Performance - SW Infiltration
Investigation
UWWTR investigation ongoing, Operational investigation completed
Improvement
No improvement action in reporting period
WFD catchment
Danby Beck catchment (trib of Esk) (GB104027068110)
Outlet location
NZ6930004400 (OS grid reference) · View on Apple Maps
EA ID / permit
YWS00043 · Permit applied for · company name: BOTTON/STW

Permit applied for

Inlet overflow at sewage works · discharges to Permit applied for

Spills 2025
21 (162 hours) · down 5% on 2024
Spills 2024
22 (110 hours)
Long-term average
29.8 spills a year (monitored since 2022)
Monitor uptime
100% of the year
Investigation
UWWTR investigation ongoing, Operational investigation completed
Improvement
No improvement action in reporting period
WFD catchment
Skeeby/Holme/Dalton Bk from Source to River Swale (GB104027069180)
Outlet location
NZ1123209943 (OS grid reference) · View on Apple Maps
EA ID / permit
YWS02291 · Permit applied for · company name: NEWSHAM/STW

Permit applied for

Inlet overflow at sewage works · discharges to Permit applied for

Spills 2025
22 (108 hours)
Spills 2024
- (- hours)
Long-term average
22.0 spills a year (monitored since 2025)
Monitor uptime
96% of the year
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
WFD catchment
Sand Beck from Source to River Swale (GB104027069020)
Outlet location
SE1535899617 (OS grid reference) · View on Apple Maps
EA ID / permit
YWS02292 · Permit applied for · company name: HUDSWELL/STW

Permit applied for

Storm tank at sewage works · discharges to Permit applied for

Spills 2025
14 (99 hours) · down 66% on 2024
Spills 2024
41 (470 hours)
Long-term average
47.3 spills a year (monitored since 2020)
Monitor uptime
100% of the year
Investigation
UWWTR investigation ongoing, Operational investigation completed
Improvement
No improvement action in reporting period
WFD catchment
Holbeck from Source to Marrs Beck (GB104027068420)
Outlet location
SE6220077300 (OS grid reference) · View on Apple Maps
EA ID / permit
YWS00792 · Permit applied for · company name: GILLING EAST/STW

Permit applied for

Inlet overflow at sewage works · discharges to Permit applied for

Spills 2025
31 (51 hours) · down 31% on 2024
Spills 2024
45 (65 hours)
Long-term average
52.2 spills a year (monitored since 2020)
Monitor uptime
100% of the year
High-spill reason (company)
Not asset maintenance - hydraulic capacity
Investigation
UWWTR investigation ongoing, Operational investigation completed
Improvement
Operational improvement completed
WFD catchment
Frickley Beck from Source to Ea Beck (GB104027063140)
Outlet location
SE4820008300 (OS grid reference) · View on Apple Maps
EA ID / permit
YWS00138 · Permit applied for · company name: HOOTON PAGNELL/STW

Permit applied for

Inlet overflow at sewage works · discharges to Permit applied for

Spills 2025
7 (42 hours) · down 13% on 2024
Spills 2024
8 (5.0 hours)
Long-term average
5.0 spills a year (monitored since 2023)
Monitor uptime
95% of the year
Investigation
No investigation activity in reporting period
Improvement
No improvement action in reporting period
WFD catchment
Sleddale Beck from Source to River Esk (GB104027068170)
Outlet location
NZ6630010300 (OS grid reference) · View on Apple Maps
EA ID / permit
YWS00044 · Permit applied for · company name: COMMONDALE/STW

Permit applied for

Inlet overflow at sewage works · discharges to Permit applied for

Spills 2025
3 (0.8 hours) · down 25% on 2024
Spills 2024
4 (3.5 hours)
Long-term average
8.3 spills a year (monitored since 2020)
Monitor uptime
100% of the year
Investigation
Operational investigation completed
Improvement
No improvement action in reporting period
WFD catchment
Catter Beck/Hutton Beck from source to River Seven (GB104027068550)
Outlet location
SE7350087400 (OS grid reference) · View on Apple Maps
EA ID / permit
YWS00167 · Permit applied for · company name: APPLETON LE MOOR/STW

How the estimate works

  1. Dry-weather flow (DWF) = population × water use per person × (1 + infiltration). Water use is 136.5 L per person per day, England's per-capita consumption for 2024-25 [EA]. Infiltration of groundwater into sewers is taken as 0-40% of that flow [Escritt, via HBF]. The Environment Agency defines DWF as PG + I + E [EA].
  2. Population. The size of each works comes from the load entering it as reported under the Urban Waste Water Treatment Directive, in population equivalents (1 p.e. = 60 g of BOD a day) [UWWTD]. We treat population equivalent as population. That overstates flow where trade effluent adds load, and no official source links the two. Works serving fewer than 2,000 p.e. are not reported, so their size has to be entered by hand.
  3. Low spill rate = DWF. This is the method used by Giakoumis & Voulvoulis (2026), which they note likely underestimates storm loads [G&V].
  4. High spill rate = Formula A − flow to full treatment = (DWF + 1360P) − 3DWF. This is the largest flow the permit expects the storm tanks to handle before it passes on to treatment or overflows [EA]. The central rate is the geometric mean of the low and high rates.
  5. Volume = spill rate × hours spilling, with hours taken from the event duration monitor.
  6. Pollution = volume × published storm-sewage concentrations [Botturi et al.] [US EPA]. Organic load is also shown as person-days of untreated sewage at 60 g of BOD per person per day [UWWTD].

What this cannot tell you. It gives no real flow for any single spill, and no effect on the river or sea, which depends on the flow, tide and the other pressures on the water at the time. It gives no figure for spills from overflows on the sewer network, which serve catchments of unknown size. It is a way to put hours into rough physical terms, not a substitute for flow monitoring.

Sources

  1. EA: Water companies - environmental permits for storm overflows and emergency overflows
  2. EA: Water resources 2024 to 2025 - per capita consumption
  3. HBF: Foul sewer design - historic conventions (citing Escritt 1984 on infiltration)
  4. Giakoumis & Voulvoulis (2026), Environ. Sci.: Water Res. Technol., doi:10.1039/D5EW00860C
  5. Botturi et al. (2021), Crit. Rev. Environ. Sci. Technol. 51:1585 - CSO quality review, Table 2
  6. US EPA (2004) Report to Congress on CSOs and SSOs, chapter 4
  7. Urban Waste Water Treatment Directive, Article 2(6): 1 p.e. = 60 g BOD5/day
  8. Olympic-size swimming pool: 2,500 m³ at the nominal 2 m depth

← All Yorkshire Water works · Contains Environment Agency data licensed under the Open Government Licence v3.0. Spill start and stop times: © Environment Agency copyright and/or database right 2026. All rights reserved. They are water-company data and have not been verified by the Environment Agency. Works size: EEA Waterbase UWWTD. How to read the data.