Chacewater STW So Chacewater

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

11
Spills in 2025: 10.3
Recorded hours: 96.3%
Monitor operation: 5
Years listed

Current status unknown

Checking the latest monitor report…

How it compares in 2025

Chacewater STW So Chacewater recorded 11 spills in 2025. That is more than 49% of the 14,239 overflows in England with a reported figure, and ranks 6,918th nationally. Among South West Water overflows it ranks 840th of 1,357; the median South West Water overflow recorded 21 spills. On the Upper Carnon River waterbody it ranks 4th of 4.

Group	Rank by spills	Median spills	Median hours
This outlet	–	11	10.3
England	6,918th of 14,239	11	22.3
South West Water	840th of 1,357	21	39.4
Upper Carnon River	4th of 4	39.5	230.6

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 2021 to 2025, the reported count went from 30 to 11 spills. The highest count was 44 in 2023 and the lowest was 10 in 2022. The monitor worked for less than 90% of 2022, 2023, 2024, 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	11	10.3 hours	96.3%	Official data
2024	31	222.7 hours	75.6%Low coverage	Official data
2023	44	589.8 hours	48.3%Low coverage	Official data
2022	10	109.6 hours	53%Low coverage	Official data
2021	30	272.2 hours	100%	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: NRA-SW-6619
Activity reference: A2
Grid reference: SW75274409
Waterbody ID: GB108048001160Official 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 0.3 km south-east of the Chacewater reference point in the ONS built-up areas data.

Area and water pages

Upper Carnon River 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

Chacewater STW SSO Chacewater
South West Water · (S) River Carnon
Current status unknown

Chacewater Brook CSO Truro
South West Water · Carnon River
Current status unknown
Blackwater STW So Blackwater
South West Water · (S) River Carnon
Current status unknown
Sparry Ln CSO Carharrick
South West Water · Carnon River (S)
Current status unknown

Questions about Chacewater STW So Chacewater

Who operates Chacewater STW So Chacewater?: South West Water is the operator named in the annual record. The permit reference is NRA-SW-6619.
Where does Chacewater STW So Chacewater discharge?: The source names (S) River Carnon as the receiving water. This does not show how far a discharge travelled.
How many times did Chacewater STW So Chacewater spill in 2025?: The 2025 return records 11 counted spill events and 10.3 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 96.3% of the reporting period, so the annual figures cover most of the year. They still do not measure discharge volume.
Is Chacewater STW So Chacewater 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 Chacewater STW So Chacewater?: 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 Chacewater STW So Chacewater compare with other overflows?: Chacewater STW So Chacewater recorded 11 spills in 2025. That is more than 49% of the 14,239 overflows in England with a reported figure, and ranks 6,918th nationally. Among South West Water overflows it ranks 840th of 1,357; the median South West Water overflow recorded 21 spills. On the Upper Carnon River waterbody it ranks 4th of 4. 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.