Outside 5 Trevarrack Lane CSO

Storm overflow run by South West Water, discharging into Local Stream.

Storm overflow on the sewer network Bathing water St. Ives constituency

Linked bathing water: Long Rock, 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 (1 day ago).
Times are UK time. Company feed updated just now

"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
28spills
9.6 h discharging on 28 days · counted by us, not yet official
2025 official
48spills
21 h · −9% on 2024
Rank in South West Water
#358
of 1,357 overflows by 2025 spills (1 = most)
Monitor in 2025
100% working
Long-term average 97.0 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
116 spills · 542 hmonitor 92.0%
2022
106 spills · 262 hmonitor 95.0%
2023
59 spills · 29 hmonitor 100%
2024
53 spills · 26 hmonitor 100%
2025
48 spills · 21 hmonitor 100%
2026so far
28 spills · 9.6 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
Not asset maintenance - hydraulic capacity
Investigation
Operational investigation completed
Improvement work
Env Act (SODRP) improvement ongoing, Bathing Water and/or Shellfish Water improvement ongoing
Monitored since
2010
Water body
Trevaylor Stream

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

108 discharge periods since 2 Jan 2025. 98 of them come from South West Water's own event-duration-monitoring records (published on Stream, Jan 2025 – May 2026); the live feed adds anything after that. The official annual count is the figure to quote.

Show 30 earlier (of 108)
StartedEndedDischarge time
11 min
3 min
3 min
15 min
18 min
42 min
30 min
12 min
21 min
4 min
19 min
12 min
8 min
13 min
40 min
16 min
14 min
7 min
6 min
6 min
29 min
10 min
3 min
23 min
3 min
14 min
8 min
5 min
4 min
3 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 158 raw blocks were merged into 108 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 : 4 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 4 states
SeenStatusSinceLatest discharge
Not discharging →
Not discharging →
Discharging → no end yet
Not discharging →

Rain nearby last 30 days

Nearest live rain gauge: Rainfall gauge nr Penzance, 2.9 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
Penzance Alverton (Lariggan River) · 2.2 km
Nearest rain gauge
Council area
Cornwall
South West Water's own name for it
GULVAL TREVARRACK LANE_CSO_PENZANCE
Site reference
SBB00893 · permit 301820
Coordinates
50.12992, -5.52863

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 St. Ives 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 St. Ives

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.