Storm overflow register · Northumbrian Water

Lowick sewage works: storm overflow spills 2025

Lowick sewage treatment works, run by Northumbrian Water, has 2 monitored storm overflows discharging to Tributary of the Low. In 2025 they recorded 117 spills totalling 510 hours, against 94 spills and 392 hours in 2024. By hours spilling, it ranks 34 of 183 Northumbrian 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.

JanFebMarAprMayJunJulAugSepOctNovDecLowick Sewage…2 spills, 2.8 h, 1 Jan to 1 Jan7 spills, 60.2 h, 5 Jan to 8 Jan9 Jan 2025 09:00 GMT, 8 min11 spills, 17.4 h, 27 Jan to 28 Jan6 spills, 7.3 h, 11 Feb to 12 Feb3 spills, 0.4 h, 13 Feb to 13 Feb3 spills, 0.8 h, 14 Feb to 14 Feb16 spills, 7.9 h, 15 Feb to 17 Feb20 Feb 2025 01:52 GMT, 30 min22 Mar 2025 20:59 GMT, 38 min29 May 2025 02:48 GMT, 5.4 h8 Jun 2025 19:04 GMT, 20 min2 spills, 2.5 h, 9 Jun to 9 Jun3 spills, 2.4 h, 14 Jun to 14 Jun16 Jun 2025 04:32 GMT, 2.8 h3 spills, 1.7 h, 22 Jun to 22 Jun8 spills, 5.9 h, 2 Jul to 2 Jul5 Jul 2025 15:54 GMT, 24 min7 Jul 2025 17:56 GMT, 94 min2 spills, 1.8 h, 19 Jul to 19 Jul3 Sep 2025 17:06 GMT, 86 min2 spills, 3.7 h, 24 Oct to 25 Oct8 spills, 41 h, 13 Nov to 14 Nov6 spills, 18.2 h, 18 Nov to 19 Nov4 spills, 6.4 h, 20 Nov to 21 Nov21 spills, 82.3 h, 23 Nov to 27 Nov26 spills, 45.4 h, 29 Nov to 2 Dec59 spills, 70.1 h, 6 Dec to 10 Dec12 Dec 2025 06:08 GMT, 32 minLowick Sewage…24 Jan 2025 03:35 GMT, 2 min27 Jan 2025 04:19 GMT, 1 min10 Feb 2025 13:08 GMT, 1 min2 spills, 0.1 h, 22 Mar to 22 Mar2 spills, 0.3 h, 16 Apr to 16 Apr4 spills, 0.5 h, 24 May to 24 May24 May 2025 22:08 GMT, 8 min4 spills, 0.1 h, 26 May to 27 May29 May 2025 02:25 GMT, 13 min3 Jun 2025 12:38 GMT, 6 min2 spills, 0.1 h, 5 Jun to 5 Jun3 spills, 0.3 h, 7 Jun to 7 Jun2 spills, 0.1 h, 8 Jun to 8 Jun9 Jun 2025 19:31 GMT, 1 min3 spills, 0.3 h, 14 Jun to 14 Jun16 Jun 2025 04:29 GMT, 4 min2 spills, 0.1 h, 21 Jun to 22 Jun2 spills, 0.1 h, 26 Jun to 26 Jun2 spills, 0.9 h, 7 Jul to 7 Jul6 spills, 2.4 h, 14 Jul to 15 Jul13 spills, 3.7 h, 19 Jul to 19 Jul31 Jul 2025 21:22 GMT, 36 min4 Aug 2025 05:20 GMT, 40 min7 spills, 3.2 h, 3 Sep to 3 Sep2 spills, 0.2 h, 4 Sep to 4 Sep2 spills, 1.8 h, 10 Sep to 11 Sep2 spills, 0.3 h, 13 Sep to 13 Sep9 spills, 2.1 h, 14 Sep to 16 Sep8 spills, 2.6 h, 20 Sep to 20 Sep3 spills, 2.5 h, 1 Oct to 1 Oct4 spills, 2.7 h, 2 Oct to 3 Oct2 spills, 0.3 h, 5 Oct to 6 Oct7 spills, 3.4 h, 19 Oct to 20 Oct5 spills, 3.7 h, 23 Oct to 23 Oct9 spills, 5 h, 24 Oct to 24 Oct27 Oct 2025 02:20 GMT, 22 min2 spills, 0.7 h, 27 Oct to 27 Oct4 spills, 0.3 h, 1 Nov to 1 Nov4 Nov 2025 11:00 GMT, 10 min5 Nov 2025 09:32 GMT, 34 min9 Nov 2025 14:12 GMT, 22 min11 Nov 2025 12:18 GMT, 22 min18 spills, 24.6 h, 13 Nov to 14 Nov12 spills, 8.2 h, 18 Nov to 19 Nov5 spills, 1.7 h, 20 Nov to 20 Nov53 spills, 25.7 h, 23 Nov to 25 Nov3 spills, 1.5 h, 29 Nov to 29 Nov11 spills, 2.8 h, 30 Nov to 1 Dec5 spills, 1.8 h, 5 Dec to 6 Dec8 spills, 8.5 h, 7 Dec to 8 Dec7 spills, 1.7 h, 9 Dec to 9 Dec2 spills, 0.1 h, 14 Dec to 14 Dec

Hours spilling by month, 2025

0100200300Jan 2025: 81 hours spillingJanFeb 2025: 17 hours spillingFebMar 2025: 0.7 hours spillingMarApr 2025: 0.3 hours spillingAprMay 2025: 6.3 hours spillingMayJun 2025: 11 hours spillingJunJul 2025: 17 hours spillingJulAug 2025: 0.7 hours spillingAugSep 2025: 12 hours spillingSepOct 2025: 22 hours spillingOctNov 2025: 224 hours spillingNovDec 2025: 118 hours spillingDec
Hours, measured by the event duration monitor.

Longest single spills

Started (GMT)OverflowDuration
23 Nov 2025, 11:20Lowick Sewage Treatment Works3.0 days
5 Jan 2025, 11:15Lowick Sewage Treatment Works2.0 days
1 Dec 2025, 03:40Lowick Sewage Treatment Works1.3 days
13 Nov 2025, 04:29Lowick Sewage Treatment Works1.3 days
7 Dec 2025, 15:42Lowick Sewage Treatment Works20.3 h

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 estimate8,732 m³range 3,478 - 21,921 m³
In litres8.7 millionrange 3.5 million - 21.9 million L
Olympic swimming pools3.5at 2,500 m³ each
Organic load, as people's raw sewage13,098person-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) 139 kg786 kg4,384 kg 40 / 90 / 200 mg/L
Low/high: Europe range, Ellis & Jenkins 2005; typical: UK, Ellis & Jenkins 2005 (both via botturi)
Suspended solids 365 kg3,711 kg15,805 kg 105 / 425 / 721 mg/L
Low/high: Europe range; typical: UK, Ellis & Jenkins 2005 (via botturi)
Ammonium-N 6.6 kg55 kg204 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 4.2 kg23 kg118 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 347.8 billion organisms8.7 trillion organisms219.2 trillion 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.

Lowick Sewage Treatment Works

Storm tank at sewage works · discharges to Tributary of the Low

Spills 2025
52 (392 hours) · up 8% on 2024
Spills 2024
48 (387 hours)
Long-term average
41.5 spills a year (monitored since 2021)
Monitor uptime
100% of the year
High-spill reason (company)
Not asset maintenance - Hydraulic capacity
Investigation
Env Act (SODRP) investigation ongoing, Operational investigation completed
Improvement
Operational improvement ongoing
WFD catchment
South Low from Source to Haggerston Bridge (GB103021073221)
Outlet location
NU0256239690 (OS grid reference) · View on Apple Maps
EA ID / permit
NWL00822 · 210/A/0854

Lowick Sewage Treatment Works

Inlet overflow at sewage works · discharges to Tributary of the Low

Spills 2025
65 (118 hours) · up 41% on 2024
Spills 2024
46 (4.8 hours)
Long-term average
39.5 spills a year (monitored since 2020)
Monitor uptime
77% of the year · Comms failure / issue
High-spill reason (company)
Not asset maintenance - Hydraulic capacity
Investigation
Env Act (SODRP) investigation ongoing, Operational investigation completed
Improvement
Operational improvement ongoing
WFD catchment
South Low from Source to Haggerston Bridge (GB103021073221)
Outlet location
NU0256239690 (OS grid reference) · View on Apple Maps
EA ID / permit
NWL00821 · 210/A/0854

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 Northumbrian 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.