Ponsanooth STW SSO

Storm overflow run by South West Water, discharging into River Kennal.

Inlet storm overflow at sewage treatment works Truro and Falmouth constituency
Right now
Discharging now
Since on · 2 h 40 min so far.
Times are UK time. Company feed updated 4 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
59spills
1,513 h discharging on 57 days · counted by us, not yet official
2025 official
126spills
2,646 h · −26% on 2024
Rank in South West Water
#43
of 1,357 overflows by 2025 spills (1 = most)
Monitor in 2025
100% working
Long-term average 97.8 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.

2022
0 spills · 0 h
2023
94 spills · 2,076 hmonitor 100%
2024
171 spills · 3,687 hmonitor 99.6%
2025
126 spills · 2,646 hmonitor 100%
2026so far
59 spills · 1,513 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
Performance - SW Infiltration
Long-term review
Not asset maintenance - hydraulic capacity
Investigation
UWWTR investigation ongoing, Operational investigation completed
Improvement work
No improvement action in reporting period
Monitored since
2021
Water body
Kennal

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

46 discharge periods since 5 Jan 2025, 1 still open. 45 of them come from South West Water's own event-duration-monitoring records (published on Stream, Jan 2025 – Mar 2026); the live feed adds anything after that. The official annual count is the figure to quote.

Show 30 earlier (of 46)
StartedEndedDischarge time
20 h 0 min
20 h 42 min
1 h 22 min
4 d 14 h
46 min
1 h 7 min
4 h 19 min
3 h 9 min
19 h 47 min
19 h 52 min
6 d 4 h
5 h 6 min
3 h 5 min
1 d 6 h
2 h 34 min
1 h 7 min
5 h 56 min
1 h 34 min
2 h 12 min
14 h 10 min
17 h 32 min
10 h 48 min
14 h 24 min
12 d 19 h
4 d 15 h
14 h 42 min
17 h 38 min
9 h 14 min
19 h 58 min
3 d 22 h

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 63 raw blocks were merged into 46 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 : 2 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 2 states
SeenStatusSinceLatest discharge
Discharging → no end yet
Not discharging →

Rain nearby last 30 days

Nearest live rain gauge: Rainfall gauge nr Gwennap, 3.4 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
Ponsanooth (River Kennall) · 0.2 km
Nearest rain gauge
Council area
Cornwall
South West Water's own name for it
PONSANOOTH STW_SSO_PONSANOOTH
Site reference
SBB00957 · permit NRA-SW-1484
Coordinates
50.19782, -5.13449

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 Truro and Falmouth 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: © 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. Constituency and council area from the EA's return: contains OS data © Crown copyright and database right 2026.