Cowfold WwTW

Storm overflow run by Southern Water, discharging into Cowfold Stream Trib River Adur.

Inlet storm overflow at sewage treatment works Horsham constituency
Right now
Not discharging
Last discharge ended on (144 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
39spills
512 h discharging on 37 days · counted by us, not yet official
2025 official
0spills
0 h · −100% on 2024
Rank in Southern Water
#797
of 970 overflows by 2025 spills (1 = most)
Monitor in 2025
100% working
Long-term average 3.6 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 Southern Water's monitor log and the live feed. The official figure is published next spring.

2024
2 spills · 3.2 hmonitor 99.9%
2025
0 spills · 0 hmonitor 100%
2026so far
39 spills · 512 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

Southern Water runs another overflow within 300 m that also discharges into Cowfold Stream Trib River Adur. They share the sewer and the storm, so one outlet's figures are only part of what reaches the water.

0m Cowfold WwTWdischargingSWS00216Cowfold SSO - 115726 45spills in 2025

This overflow (Cowfold CEO - 115981): 0 spills in 2025. Distances are between the published outlet points. The names in brackets are Southern Water's own, from its return.

Downstream of this overflow

The next gauge downstream that the river map places is Beeding Bridge (River Adur), 15.7 km along the river.

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

High-spill review
High spill threshold not met
Investigation
No investigation activity in reporting period
Improvement work
No improvement action in reporting period
Monitored since
2018
Water body
Cowfold Stream

"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

97 discharge periods since 14 Feb 2024. 97 of them come from Southern Water's own event-duration-monitoring records (from its Rivers and Seas Watch service, Feb 2024 – Sep 2026); the live feed adds anything after that. The official annual count is the figure to quote.

Show 30 earlier (of 97)
StartedEndedDischarge time
17 h 39 min
2 min
2 min
19 h 41 min
14 min
1 h 0 min
2 min
3 h 31 min
17 min
25 min
3 h 14 min
40 min
4 h 4 min
7 min
4 min
2 d 20 h
2 min
5 min
30 min
3 h 36 min
1 d 4 h
1 d 13 h
20 min
2 min
23 min
2 min
10 min
1 d 16 h
9 min
30 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 185 raw blocks were merged into 97 continuous discharge periods (gaps under 15 min joined).

What the feed showed

FloodRadar's own record of every change of state Southern Water'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 Horsham, 0.1 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
SAKEHAM GS · 2.9 km
Nearest rain gauge
Council area
Horsham District
Southern Water's own name for it
Cowfold CEO - 115981
Site reference
SWS00215 · permit W00356
Coordinates
50.98425, -0.26999

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 Horsham 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.

Find the MP for Horsham

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: © Southern 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. Spill-event history: Southern Water's Rivers and Seas Watch release history (riversandseaswatch.southernwater.co.uk), © Southern Water. Shown by FloodRadar: only releases Southern Water marks Genuine and that have ended; those it marks Not Genuine or still has under review are left out. 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.