Storm overflow register · Anglian Water

Winteringham sewage works: storm overflow spills 2025

Winteringham sewage treatment works, run by Anglian Water, has 1 monitored storm overflow discharging to R.Humber T. In 2025 it recorded 77 spills totalling 353 hours, against 141 spills and 837 hours in 2024. By hours spilling, it ranks 63 of 419 Anglian Water works, where 1 spilled longest.

Works size: 9,051 population equivalent (WINTERINGHAM STW, UWWTD 2018). Used for the spill volume estimate.

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.

JanFebMarAprMayJunJulAugSepOctNovDecWinteringham Water…20 spills, 4.5 h, 1 Jan to 1 Jan117 spills, 52.9 h, 5 Jan to 8 Jan72 spills, 9.5 h, 26 Jan to 29 Jan3 spills, 0.2 h, 24 Feb to 24 Feb3 spills, 0.2 h, 26 Feb to 26 Feb16 Mar 2025 08:22 GMT, 6 min29 Mar 2025 14:10 GMT, 2 min3 spills, 0.1 h, 15 May to 15 May24 May 2025 05:08 GMT, 6 min6 spills, 0.5 h, 5 Jun to 6 Jun22 Jun 2025 23:24 GMT, 4 min4 spills, 0.3 h, 2 Jul to 2 Jul5 spills, 0.3 h, 6 Jul to 6 Jul2 spills, 0.1 h, 29 Aug to 29 Aug6 spills, 2.8 h, 3 Sep to 4 Sep3 spills, 0.3 h, 10 Sep to 10 Sep6 spills, 0.5 h, 11 Sep to 11 Sep6 spills, 0.3 h, 17 Sep to 17 Sep27 spills, 9.5 h, 20 Sep to 21 Sep13 spills, 1.3 h, 3 Oct to 3 Oct2 spills, 0.4 h, 11 Oct to 11 Oct3 spills, 0.3 h, 13 Oct to 13 Oct14 Oct 2025 17:08 GMT, 28 min2 spills, 0.4 h, 20 Oct to 20 Oct2 spills, 0.4 h, 23 Oct to 23 Oct7 spills, 1.4 h, 4 Nov to 4 Nov16 spills, 5.6 h, 10 Nov to 11 Nov8 spills, 1.3 h, 12 Nov to 13 Nov93 spills, 28.8 h, 14 Nov to 17 Nov19 spills, 3.8 h, 18 Nov to 19 Nov20 Nov 2025 23:26 GMT, 12 min33 spills, 6.1 h, 22 Nov to 24 Nov744 spills, 219.9 h, 28 Nov to 25 Dec26 Dec 2025 13:44 GMT, 12 min

Estimated spill volume by month, 2025

Hours spilling each month × the estimated spill rate for a works of this size. The bars are central estimates and the whiskers show the low-high range. Method.

020k40k60k80kJan 2025: 67 h spilling ≈ 10,375 m³ (range 4,133-26,047 m³)JanFeb 2025: 0.4 h spilling ≈ 62 m³ (range 25-156 m³)FebMar 2025: 0.1 h spilling ≈ 16 m³ (range 6.2-39 m³)MarApr 2025: 0.0 h spilling ≈ 0.0 m³ (range 0.0-0.0 m³)AprMay 2025: 0.2 h spilling ≈ 31 m³ (range 12-78 m³)MayJun 2025: 0.6 h spilling ≈ 93 m³ (range 37-234 m³)JunJul 2025: 0.6 h spilling ≈ 93 m³ (range 37-234 m³)JulAug 2025: 0.1 h spilling ≈ 16 m³ (range 6.2-39 m³)AugSep 2025: 13 h spilling ≈ 2,063 m³ (range 822-5,178 m³)SepOct 2025: 3.3 h spilling ≈ 512 m³ (range 204-1,285 m³)OctNov 2025: 85 h spilling ≈ 13,136 m³ (range 5,232-32,977 m³)NovDec 2025: 183 h spilling ≈ 28,318 m³ (range 11,280-71,094 m³)Dec
Cubic metres (m³), estimate. Hours are measured by the event duration monitor.

Longest single spills

Started (GMT)OverflowDurationEstimated volume
6 Jan 2025, 00:00Winteringham Water Recycling Centre1.0 days1,483 - 9,344 m³
30 Nov 2025, 00:00Winteringham Water Recycling Centre22.1 h1,367 - 8,617 m³
9 Dec 2025, 07:42Winteringham Water Recycling Centre16.3 h1,007 - 6,346 m³
19 Dec 2025, 00:00Winteringham Water Recycling Centre11.4 h702 - 4,426 m³
5 Jan 2025, 17:58Winteringham Water Recycling Centre6.0 h373 - 2,349 m³

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.

Volume, central estimate54,714 m³range 21,794 - 137,361 m³
In litres54.7 millionrange 21.8 million - 137.4 million L
Olympic swimming pools22at 2,500 m³ each
Organic load, as people's raw sewage82,070person-days of untreated BOD

Assumed spill rate while spilling: 17.2 - 108.2 L/s (central 43.1 L/s), from a dry-weather flow of 17.2 L/s.

Pollutant releasedLowCentralHighConcentration used (low / typical / high)
BOD₅ (organic load) 872 kg4,924 kg27,472 kg 40 / 90 / 200 mg/L
Low/high: Europe range, Ellis & Jenkins 2005; typical: UK, Ellis & Jenkins 2005 (both via botturi)
Suspended solids 2,288 kg23,253 kg99,037 kg 105 / 425 / 721 mg/L
Low/high: Europe range; typical: UK, Ellis & Jenkins 2005 (via botturi)
Ammonium-N 41 kg345 kg1,277 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 26 kg142 kg742 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 2.2 trillion organisms54.7 trillion organisms1.4 × 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.

Winteringham Water Recycling Centre

Inlet overflow at sewage works · discharges to R.Humber T

Spills 2025
77 (353 hours) · down 45% on 2024
Spills 2024
141 (837 hours)
Long-term average
109.0 spills a year (monitored since 2024)
Monitor uptime
100% of the year
High-spill reason (company)
Performance - Asset configuration (e.g. PS/rising main/storm tanks)
Investigation
Env Act (SODRP) investigation ongoing, Operational investigation completed
Improvement
Env Act (SODRP) improvement ongoing, Operational improvement ongoing
WFD catchment
Ancholme from Bishopbridge to the Humber (GB104029067520)
Outlet location
SE9473022230 (OS grid reference) · View on Apple Maps
EA ID / permit
AWS01512 · AW3TS154 · company name: Winteringham WRC

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 Anglian 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.