Mullion Transfer PS

Storm overflow run by South West Water, discharging into Polurrian Cove.

Storm discharge at pumping station Bathing water

Linked bathing water: Polurrian Cove, classified Excellent for 2025. Named in the company’s return to the Environment Agency. A name opens that bathing water’s official profile, with any pollution warning in the season. The classification is the Environment Agency’s for that bathing season, from all its samples there: it is not a reading of the water today, and it does not say what part this overflow played.

Right now
Not discharging
Last discharge ended on (2 days ago).
Times are UK time. Company feed updated 2 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
16spills
95 h discharging on 16 days · counted by us, not yet official
2025 official
9spills
12 h · −57% on 2024
Rank in South West Water
#880
of 1,357 overflows by 2025 spills (1 = most)
Monitor in 2025
100% working
Long-term average 25.9 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 South West Water's monitor log and the live feed. The official figure is published next spring.

2021
23 spills · 40 hmonitor 100%
2022
18 spills · 27 hmonitor 99.0%
2023
27 spills · 76 hmonitor 100%
2024
21 spills · 65 hmonitor 100%
2025
9 spills · 12 hmonitor 100%
2026so far
16 spills · 95 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.

What the 2025 return says

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

High-spill review
High spill threshold not met
Long-term review
Not Applicable - Ongoing investigation
Investigation
No investigation activity in reporting period
Improvement work
Env Act (SODRP) improvement ongoing
Monitored since
2010
Water body
Not part of a WFD catchment

"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

34 discharge periods since 15 Apr 2025. 32 of them come from South West Water's own event-duration-monitoring records (published on Stream, Apr 2025 – Feb 2026); the live feed adds anything after that. The official annual count is the figure to quote.

Show 24 earlier
StartedEndedDischarge time
3 min
3 min
6 h 53 min
1 h 21 min
1 h 23 min
1 d 16 h
17 min
3 min
8 h 55 min
12 min
39 min
2 min
2 h 47 min
1 h 6 min
15 h 2 min
2 h 29 min
21 min
4 min
21 min
6 min
33 min
13 min
12 min
1 h 15 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 82 raw blocks were merged into 34 continuous discharge periods (gaps under 15 min joined).

What the feed showed

FloodRadar's own record of every change of state South West Water's live feed has shown for this overflow, kept since : 3 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 3 states
SeenStatusSinceLatest discharge
Not discharging →
Discharging → no end yet
Not discharging →

Rain nearby last 30 days

Nearest live rain gauge: Rainfall gauge nr Mullion, 3.9 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
LOE BAR · 5.7 km
Nearest rain gauge
South West Water's own name for it
MERES VALLEY SPST_PSCSOEO_MULLION
Site reference
SBB00819 · permit 302947
Coordinates
50.02538, -5.26134

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.

Live status: © South West 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 "via Top of the Poops", 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.