Lynwood House CSO Der44

Storm overflow run by Northumbrian Water, discharging into Smallhope Burn.

Storm overflow on the sewer network North Durham constituency
Right now
Not discharging
Last discharge ended on (2 days ago).
Times are UK time. Company feed updated 3 min ago

"Not discharging" means the company's monitor reports no discharge right now — not that the water is clean. The feed publishes status only; no discharge volume is measured.

2026 so far
40spills
at least 165 h discharging on 44 days · live feed, before 28 Feb via Top of the Poops, not yet official · 8 discharges whose end the feed did not report (counted, no hours)
2025 official
53spills
185 h · −21% on 2024
Rank in Northumbrian Water
#99
of 1,547 overflows by 2025 spills (1 = most)
Monitor in 2025
99.9% working
Long-term average 65.2 spills a year

Year by year

The Environment Agency's official annual returns, counted the EA's way (12/24-hour spills). 2026 is our own running count, the same way, from the live feed: our own log of it begins on 28 February, and the discharges before that are Top of the Poops' record of the same feed. The feed reports only each overflow's latest discharge, so a discharge it moved past before we saw it end is counted as one spill with no hours: the hours are a floor. The official figure is published next spring.

2021
71 spills · 281 hmonitor 97.9%
2022
61 spills · 123 hmonitor 99.1%
2023
78 spills · 503 hmonitor 99.8%
2024
67 spills · 356 hmonitor 99.0%
2025
53 spills · 185 hmonitor 99.9%
2026so far
40 spills · at least 165 h

A spill is the EA's 12/24-hour count: the first 12 hours of a discharge count as one, each further 24 hours with discharge as one more. "Monitor" is the share of that year the monitor was working, so a 0 beside a working monitor is a real zero; "no data" means the monitor produced no usable data that year — not zero. Years before 2024 are matched to this site by name and location, because the EA's site IDs changed that year; a monitor figure beside one of them means the outlet's permit confirms the match.

Twin outlet

Northumbrian Water runs another overflow within 300 m that also discharges into Smallhope Burn. They share the sewer and the storm, so one outlet's figures are only part of what reaches the water.

205m Railway Sreet CSONWL01079Railway Sreet CSO 36spills in 2025

This overflow: 53 spills in 2025. Distances are between the published outlet points.

Downstream of this overflow

The next gauge downstream that the river map places is Burn Hall (River Browney), 19.7 km along the river.

Water-sampling points downstream

The nearest Environment Agency sampling points the river map places below Burn Hall. Points between this overflow and that gauge cannot be put in order with it on the map, so they are not listed.

A sample is dated: it is not the river now, and its results are on its own page. A sample taken after a discharge does not show that the discharge caused what was measured. Samples: Environment Agency Water Quality Archive, © Environment Agency and/or database right 2026, Open Government Licence v3.0.

A river gauge measures the level of the river; it does not measure this overflow's discharge, and a spill does not by itself explain a change there. Traced on OS Open Rivers (edition 2026-04), which leaves out many small channels.

Contains OS data © Crown copyright and database rights 2026.

What the 2025 return says

From Northumbrian Water's annual return to the Environment Agency for this overflow.

High-spill review
Not asset maintenance - Hydraulic capacity
Investigation
Env Act (SODRP) investigation ongoing
Improvement work
No improvement action in reporting period
Monitored since
2013
Water body
Smallhope Burn from Source to Browney, Stocke

This overflow spilled often enough to trigger the EA's high-spill review; the review line is the company's own stated reason.

Discharges we have recorded

746 discharge periods since 9 Jan 2020, 8 whose end the feed never gave. 658 of them come from Northumbrian Water's own event-duration-monitoring records (published on Stream, Jan 2020 – Dec 2025); the live feed adds anything after that. The official annual count is the figure to quote.

Show 30 earlier (of 746)
StartedEndedDischarge time
6 min
1 h 22 min
1 h 10 min
2 min
4 min
38 min
46 min
1 h 0 min
1 h 0 min
34 min
1 h 24 min
not captured, before not captured
not captured, before not captured
1 h 24 min
1 h 18 min
52 min
24 min
1 h 38 min
3 h 12 min
24 min
34 min
46 min
18 min
2 h 56 min
1 h 38 min
34 min
not captured, before not captured
2 h 32 min
1 h 16 min
not captured, before not captured

The year figures above use the EA's 12/24-hour counting method, so they are comparable with the official figures; the monitor log's 936 raw blocks were merged into 746 continuous discharge periods (gaps under 15 min joined).

What the feed showed

FloodRadar's own record of every change of state Northumbrian Water's live feed has shown for this overflow, kept since : 17 states. The feed publishes its status now and its latest discharge, nothing older; the discharges above are read from this. It is here so the figures can be checked.

Show the last 17 states
SeenStatusSinceLatest discharge
Not discharging →
Discharging → no end yet
Not discharging →
Discharging → no end yet
Not discharging →
Discharging → no end yet
Not discharging →
Discharging → no end yet
Not discharging →
Discharging → no end yet
Not discharging →
Discharging → no end yet
Not discharging →
Discharging → no end yet
Not discharging →
Discharging → no end yet
Not discharging →

Rain nearby last 30 days

Nearest live rain gauge: Rainfall gauge nr Consett, 4.5 km away. Brown shading = when this overflow was discharging; ▼ = a discharge start.

Overflow shading is a timing match, not proof of cause — heavy rain and spills share a trigger. Times come from the water company’s event-duration monitor (site status only; no discharge volume is published).

Where it is

Nearest river gauge
Lanchester Front Street (Smallhope Burn) · 0.8 km
Nearest rain gauge
Council area
County Durham
Site reference
NWL00831 · permit 244/1021
Coordinates
54.81823, -1.74039

Tell me when this overflow discharges

One message when the company's monitor reports a new discharge here. At most one every 6 hours.

Setting this alert needs JavaScript. The alerts you already have are on your alerts page.

The alert repeats the monitor's status: whether the overflow is discharging, not how much or why. It can only tell you about a discharge that starts after you turn it on.

Concerned about this overflow?

Report pollution you can see or smell to the regulator straight away; the company handles complaints about the overflow itself.

Write to the MP

The Environment Agency's return places this overflow in the North Durham constituency. An MP can ask the company and the regulator questions on a constituent's behalf. These words carry the official figures; change them as you like.

The link opens Parliament's own "Find your MP", which gives the MP's name and how to write to them. FloodRadar sends nothing and keeps nothing you write. Check the constituency against your own address: an MP acts only for people who live in it.

Live status: © Northumbrian Water storm overflow activity data, licensed under CC BY 4.0. Annual spill figures: Environment Agency Event Duration Monitoring return, © Environment Agency copyright and/or database right, Open Government Licence (OGL) v3.0. Storm-overflow spill events: © the respective water company, published on Stream (data.streamwaterdata.co.uk) under CC BY 4.0. Discharges marked "EA start/stop data": Environment Agency Event Duration Monitoring storm overflow start/stop detailed data, © Environment Agency copyright and/or database right 2026, Open Government Licence v3.0; the companies' monitor records as the EA received them, not verified by the EA. Discharges marked "via Top of the Poops", and this year's figures before 28 February, come from Top of the Poops' record of the same company feed, used under CC BY-SA 4.0: the feed's own start and end times as its pages print them, not their derived hours. Times are shown in UK local time. FloodRadar republishes the monitor's status and the EA's figures; it does not measure discharges itself. Constituency and council area from the EA's return: contains OS data © Crown copyright and database right 2026.