Worsley STW

Storm overflow run by United Utilities, discharging into Little Hulton Stream.

Inlet storm overflow at sewage treatment works Bolton South and Walkden constituency
Right now
Not discharging
Last discharge ended on (13 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
13spills
at least 4.5 h discharging on 13 days · live feed, before 28 Feb via Top of the Poops, not yet official · 1 discharge whose end the feed did not report (counted, no hours)
2025 official
12spills
2.8 h · +9% on 2024
Rank in United Utilities
#1,201
of 2,242 overflows by 2025 spills (1 = most)
Monitor in 2025
100% working
Long-term average 11.4 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.

2024
11 spills · 1.8 hmonitor 100%
2025
12 spills · 2.8 hmonitor 100%
2026so far
13 spills · at least 4.5 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.

Other outlets here

United Utilities runs 2 other overflows within 300 m that also discharge into Little Hulton Stream. They share the sewer and the storm, so one outlet's figures are only part of what reaches the water.

0m Worsley STWdischargingUUP02176Worsley WwTW 72spills in 2025
0m Worsley STWdischargingUUP02177Worsley WwTW 31spills in 2025

This overflow (Worsley WwTW): 12 spills in 2025. Distances are between the published outlet points. The names in brackets are United Utilities's own, from its return.

What the 2025 return says

From United Utilities's annual return to the Environment Agency for this overflow.

High-spill review
High spill threshold not met
Long-term review
Not asset maintenance - Hydraulic capacity
Investigation
Env Act (SODRP) investigation ongoing
Improvement work
No improvement action in reporting period
Monitored since
2020
Water body
Astley Brook (Mersey)

"High spill threshold not met" means this overflow did not spill often enough to trigger the EA's formal high-spill review for that year. It is not a statement that the spills were harmless.

Discharges we have recorded

37 discharge periods since 21 Jan 2024, 1 whose end the feed never gave. 23 of them come from United Utilities's own event-duration-monitoring records (published on Stream, Jan 2024 – Nov 2025); the live feed adds anything after that. The official annual count is the figure to quote.

Show 27 earlier
StartedEndedDischarge time
1 min
1 h 12 min
3 min
46 min
30 min
9 min
23 min
2 min
10 min
8 min
15 min
8 min
28 min
19 min
9 min
8 min
9 min
11 min
1 min
12 min
13 min
1 min
15 min
23 min
1 min
12 min
10 min

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 38 raw blocks were merged into 37 continuous discharge periods (gaps under 15 min joined).

What the feed showed

FloodRadar's own record of every change of state United Utilities's live feed has shown for this overflow, kept since : 1 state. 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 1 states
SeenStatusSinceLatest discharge
Not discharging →

Rain nearby last 30 days

Nearest live rain gauge: Rainfall gauge nr Bolton, 5.1 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
Walkden The Reach (Whittle Brook) · 2.2 km
Nearest rain gauge
Council area
Salford District (B)
United Utilities's own name for it
Worsley WwTW
Site reference
UUP02178 · permit 016940139
Coordinates
53.52067, -2.42153

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 Bolton South and Walkden 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: © United Utilities 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 "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.