Latchley STW So Gunnislake

Storm overflow operated by South West Water. The source names River Tamar (S) as the receiving water.

42
Spills in 2025: 604
Recorded hours: 98.9%
Monitor operation: 5
Years listed

The reported spill count was 77 lower than in 2024. This compares event counts, not discharge volume.

Current status unknown

Checking the latest monitor report…

How it compares in 2025

Latchley STW So Gunnislake recorded 42 spills in 2025. That is more than 83% of the 14,239 overflows in England with a reported figure, and ranks 2,238th nationally. Among South West Water overflows it ranks 410th of 1,357; the median South West Water overflow recorded 21 spills. On the Lower River Tamar waterbody it ranks 4th of 10.

Group	Rank by spills	Median spills	Median hours
This outlet	–	42	604
England	2,238th of 14,239	11	22.3
South West Water	410th of 1,357	21	39.4
Lower River Tamar	4th of 10	33	164.7

Rank 1 has the most spills. Equal counts share a rank. Only overflows with a reported count are ranked. Counts do not measure volume, so a higher rank does not mean more sewage.

Annual spill history

From 2022 to 2025, the reported count went from 75 to 42 spills. The highest count was 127 in 2023 and the lowest was 42 in 2025. The monitor worked for less than 90% of 2022, 2023, so those counts may be low.Amber bars mark years when the monitor worked for less than 90% of the year.

Year	Spills	Duration	Monitor operation	Source
2025	42	604 hours	98.9%	Official data
2024	119	1,654 hours	100%	Official data
2023	127	2,059.8 hours	82.8%Low coverage	Official data
2022	75	1,247.7 hours	78%Low coverage	Official data
2021	Unknown	Unknown	Unknown	Official data

A missing figure means the source did not provide a usable value. A zero is shown as zero. Monitor operation below 90% can make comparison less reliable.

Outlet details

Water company: South West Water
Outlet type: Inlet storm overflow at a wastewater treatment works
Permit: 302129
Activity reference: A2
Grid reference: SX40837397
Waterbody ID: GB108047007860Official waterbody record ↗
Location source: Official annual grid reference
Location precision: About 10 metres
Location note: Unknown

About the name and type

The annual return lists this asset as “Inlet SO at WwTW”: inlet storm overflow at a wastewater treatment works. The overflow is at the inlet of a treatment works, where wastewater enters the works.

The waterbody link opens the Environment Agency record for the exact ID in the return. It is a source lookup; we do not import its classification.

Where it is

The recorded position is about 1.8 km north of the Chilsworthy (Cornwall) reference point in the ONS built-up areas data.

Area and water pages

Lower River Tamar waterbody →

Check the official record

Public access to this outlet is unknown. Do not enter restricted land or use this page as a route guide.

Open official source ↗

Other outlet records nearby

Chilsworthy STW So Gunnislake
South West Water · River Tamar
Current status unknown

Luckett STW Pscsoeo Callington
South West Water · Alren Stream
Current status unknown
Gunnislake No. 1 CSO Gunnislake
South West Water · River Tamar (S)
Current status unknown
Gunnislake No. 2 CSO Gunnislake
South West Water · River Tamar via SWS
Current status unknown

Questions about Latchley STW So Gunnislake

Who operates Latchley STW So Gunnislake?: South West Water is the operator named in the annual record. The permit reference is 302129.
Where does Latchley STW So Gunnislake discharge?: The source names River Tamar (S) as the receiving water. This does not show how far a discharge travelled.
How many times did Latchley STW So Gunnislake spill in 2025?: The 2025 return records 42 counted spill events and 604 hours of recorded discharge. Spills are counted with the 12/24-hour method, so this is not a count of every start signal.
Can I trust the 2025 figures for this outlet?: The monitor worked for 98.9% of the reporting period, so the annual figures cover most of the year. They still do not measure discharge volume.
Is Latchley STW So Gunnislake discharging right now?: This record is linked to a company live feed. The panel above shows the latest report we hold, with its date. That report can be old, and the monitor can be offline, so check the date before relying on it. A report that no discharge is taking place is not a water-quality result.
How accurate is the map marker?: The marker comes from the grid reference in the official annual return, which is accurate to about 10 metres. It shows the recorded outlet position, not the extent of any discharge.
What kind of outlet is Latchley STW So Gunnislake?: The annual return lists the asset type as “Inlet SO at WwTW”, which means inlet storm overflow at a wastewater treatment works. The overflow is at the inlet of a treatment works, where wastewater enters the works.
How does Latchley STW So Gunnislake compare with other overflows?: Latchley STW So Gunnislake recorded 42 spills in 2025. That is more than 83% of the 14,239 overflows in England with a reported figure, and ranks 2,238th nationally. Among South West Water overflows it ranks 410th of 1,357; the median South West Water overflow recorded 21 spills. On the Lower River Tamar waterbody it ranks 4th of 10. Ranks compare counted spill events only. They do not compare volume or harm.
Does zero spills mean the water was safe?: No. A zero means the annual return recorded zero counted spill events for this outlet and year. It is not a water-quality test, and pollution can come from other sources.