Storm overflow register · Northumbrian Water

Newbiggin sewage works: storm overflow spills 2025

Newbiggin sewage treatment works, run by Northumbrian Water, has 2 monitored storm overflows discharging to North Sea. In 2025 they recorded 139 spills totalling 866 hours, against 96 spills and 713 hours in 2024. By hours spilling, it ranks 13 of 183 Northumbrian Water works, where 1 spilled longest.

Works size: 34,181 population equivalent (NEWBIGGIN 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.

JanFebMarAprMayJunJulAugSepOctNovDecNewbiggin Sewage…7 spills, 3 h, 1 Jan to 1 Jan26 spills, 46 h, 5 Jan to 7 Jan2 spills, 1.6 h, 23 Jan to 23 Jan30 spills, 5.2 h, 26 Jan to 27 Jan8 spills, 2.3 h, 20 Feb to 20 Feb4 spills, 2.9 h, 23 Feb to 23 Feb4 spills, 1.4 h, 22 Mar to 22 Mar2 spills, 0.8 h, 1 May to 1 May2 spills, 7 h, 24 May to 24 May12 spills, 1 h, 29 May to 29 May2 spills, 0.9 h, 5 Jun to 5 Jun21 spills, 7.4 h, 7 Jun to 7 Jun3 spills, 0.5 h, 9 Jun to 9 Jun3 spills, 0.6 h, 26 Jun to 26 Jun34 spills, 9.4 h, 2 Jul to 2 Jul4 spills, 0.7 h, 7 Jul to 7 Jul16 spills, 5.2 h, 14 Jul to 14 Jul7 spills, 3.2 h, 15 Jul to 15 Jul7 spills, 9.4 h, 19 Jul to 20 Jul4 spills, 0.4 h, 11 Aug to 11 Aug3 spills, 1.3 h, 31 Aug to 31 Aug12 spills, 2.4 h, 3 Sep to 3 Sep3 spills, 1.7 h, 4 Sep to 4 Sep10 Sep 2025 20:54 GMT, 98 min25 spills, 11.8 h, 14 Sep to 16 Sep3 spills, 0.8 h, 17 Sep to 17 Sep60 spills, 29.3 h, 19 Sep to 21 Sep3 spills, 0.4 h, 27 Sep to 27 Sep16 spills, 2 h, 1 Oct to 1 Oct30 spills, 19.6 h, 2 Oct to 4 Oct6 spills, 0.4 h, 6 Oct to 6 Oct30 spills, 17.9 h, 19 Oct to 20 Oct16 spills, 0.3 h, 21 Oct to 21 Oct23 Oct 2025 09:25 GMT, 46 min5 spills, 4.6 h, 24 Oct to 25 Oct27 Oct 2025 04:18 GMT, 54 min4 spills, 1.4 h, 28 Oct to 28 Oct4 Nov 2025 09:48 GMT, 56 min8 spills, 4.2 h, 5 Nov to 5 Nov7 Nov 2025 09:41 GMT, 1 min4 spills, 0.8 h, 9 Nov to 9 Nov8 spills, 4.6 h, 11 Nov to 11 Nov32 spills, 30.7 h, 12 Nov to 14 Nov13 spills, 19.7 h, 18 Nov to 19 Nov31 spills, 30.6 h, 20 Nov to 22 Nov20 spills, 70.8 h, 23 Nov to 26 Nov6 spills, 4 h, 28 Nov to 28 Nov4 spills, 9.2 h, 29 Nov to 30 Nov14 spills, 19.4 h, 1 Dec to 2 Dec54 spills, 26.9 h, 5 Dec to 6 Dec167 spills, 52 h, 7 Dec to 10 Dec5 spills, 1.6 h, 15 Dec to 15 Dec35 spills, 4.5 h, 17 Dec to 18 Dec5 spills, 0.3 h, 22 Dec to 22 DecNewbiggin Sewage…1 Jan 2025 13:24 GMT, 2.5 h12 spills, 43.2 h, 5 Jan to 7 Jan23 Jan 2025 14:40 GMT, 78 min2 spills, 3.6 h, 26 Jan to 27 Jan3 spills, 1.7 h, 20 Feb to 20 Feb23 Feb 2025 10:46 GMT, 2.6 h22 Mar 2025 19:52 GMT, 72 min2 spills, 0.7 h, 1 May to 1 May2 spills, 6.4 h, 24 May to 24 May29 May 2025 06:26 GMT, 12 min5 Jun 2025 14:56 GMT, 46 min4 spills, 6.8 h, 7 Jun to 7 Jun9 Jun 2025 21:36 GMT, 22 min4 spills, 0.2 h, 26 Jun to 26 Jun2 spills, 8.2 h, 2 Jul to 2 Jul7 Jul 2025 19:50 GMT, 32 min3 spills, 3.6 h, 14 Jul to 14 Jul3 spills, 2.7 h, 15 Jul to 15 Jul19 Jul 2025 15:00 GMT, 9.1 h11 Aug 2025 21:16 GMT, 18 min3 spills, 1.1 h, 31 Aug to 31 Aug3 Sep 2025 12:30 GMT, 14 min4 Sep 2025 16:54 GMT, 66 min3 spills, 3.6 h, 14 Sep to 15 Sep16 Sep 2025 03:46 GMT, 16 min2 spills, 13.7 h, 20 Sep to 21 Sep4 spills, 10.1 h, 2 Oct to 3 Oct8 spills, 5.5 h, 19 Oct to 20 Oct24 Oct 2025 21:24 GMT, 116 min28 Oct 2025 00:32 GMT, 8 min3 spills, 1.4 h, 5 Nov to 5 Nov11 Nov 2025 11:04 GMT, 94 min13 Nov 2025 00:30 GMT, 28.5 h5 spills, 63 h, 18 Nov to 22 Nov2 spills, 67 h, 23 Nov to 26 Nov28 Nov 2025 12:42 GMT, 2.1 h3 spills, 7.2 h, 29 Nov to 29 Nov2 spills, 17.5 h, 1 Dec to 1 Dec6 spills, 18.4 h, 5 Dec to 6 Dec3 spills, 42.7 h, 7 Dec to 10 Dec15 Dec 2025 11:50 GMT, 66 min17 Dec 2025 20:32 GMT, 2.6 h

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.

0200k400k600kJan 2025: 106 h spilling ≈ 62,316 m³ (range 24,822-156,446 m³)JanFeb 2025: 9.4 h spilling ≈ 5,505 m³ (range 2,193-13,821 m³)FebMar 2025: 2.6 h spilling ≈ 1,523 m³ (range 607-3,823 m³)MarApr 2025: 0.0 h spilling ≈ 0.0 m³ (range 0.0-0.0 m³)AprMay 2025: 16 h spilling ≈ 9,429 m³ (range 3,756-23,673 m³)MayJun 2025: 17 h spilling ≈ 10,191 m³ (range 4,059-25,584 m³)JunJul 2025: 52 h spilling ≈ 30,455 m³ (range 12,131-76,458 m³)JulAug 2025: 3.1 h spilling ≈ 1,816 m³ (range 723-4,558 m³)AugSep 2025: 67 h spilling ≈ 39,181 m³ (range 15,607-98,367 m³)SepOct 2025: 65 h spilling ≈ 38,186 m³ (range 15,210-95,867 m³)OctNov 2025: 346 h spilling ≈ 202,818 m³ (range 80,787-509,183 m³)NovDec 2025: 187 h spilling ≈ 109,579 m³ (range 43,648-275,103 m³)Dec
Cubic metres (m³), estimate. Hours are measured by the event duration monitor.

Longest single spills

Started (GMT)OverflowDurationEstimated volume
23 Nov 2025, 07:47Newbiggin Sewage Treatment Works2.7 days15,066 - 94,960 m³
23 Nov 2025, 07:50Newbiggin Sewage Treatment Works2.6 days14,650 - 92,338 m³
5 Jan 2025, 09:21Newbiggin Sewage Treatment Works1.8 days10,241 - 64,548 m³
5 Jan 2025, 09:24Newbiggin Sewage Treatment Works1.7 days9,658 - 60,873 m³
20 Nov 2025, 09:04Newbiggin Sewage Treatment Works1.3 days7,100 - 44,748 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 estimate507,251 m³range 202,048 - 1.3 million m³
In litres507.3 millionrange 202.0 million - 1.3 billion L
Olympic swimming pools203at 2,500 m³ each
Organic load, as people's raw sewage760,876person-days of untreated BOD

Assumed spill rate while spilling: 64.8 - 408.4 L/s (central 162.7 L/s), from a dry-weather flow of 64.8 L/s.

Pollutant releasedLowCentralHighConcentration used (low / typical / high)
BOD₅ (organic load) 8,082 kg45,653 kg254,694 kg 40 / 90 / 200 mg/L
Low/high: Europe range, Ellis & Jenkins 2005; typical: UK, Ellis & Jenkins 2005 (both via botturi)
Suspended solids 21,215 kg215,581 kg918,174 kg 105 / 425 / 721 mg/L
Low/high: Europe range; typical: UK, Ellis & Jenkins 2005 (via botturi)
Ammonium-N 384 kg3,196 kg11,843 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 242 kg1,319 kg6,877 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 20.2 trillion organisms507.3 trillion organisms1.3 × 10¹⁶ 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.

Newbiggin Sewage Treatment Works

Inlet overflow at sewage works · discharges to North Sea

Spills 2025
78 (479 hours) · down 11% on 2024
Spills 2024
88 (624 hours)
Long-term average
63.9 spills a year (monitored since 2018)
Monitor uptime
100% of the year
High-spill reason (company)
Not asset maintenance - Hydraulic capacity
Investigation
Operational investigation completed
Improvement
No improvement action in reporting period
Bathing water
Newbiggin North; Newbiggin South
WFD catchment
Tyne and Wear (GB650301500002)
Outlet location
NZ3238286215&NZ3129786715 (OS grid reference) · View on Apple Maps
EA ID / permit
NWL00940 · 225/1031

Newbiggin Sewage Treatment Works

Inlet overflow at sewage works · discharges to North Sea

Spills 2025
61 (387 hours) · up 663% on 2024
Spills 2024
8 (90 hours)
Long-term average
51.3 spills a year (monitored since 2019)
Monitor uptime
100% of the year
High-spill reason (company)
Not asset maintenance - Hydraulic capacity
Investigation
Operational investigation completed
Improvement
No improvement action in reporting period
Bathing water
Newbiggin North; Newbiggin South
WFD catchment
Tyne and Wear (GB650301500002)
Outlet location
NZ3129786715 (OS grid reference) · View on Apple Maps
EA ID / permit
NWL00941 · 225/1031

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.