Harewood Rd CSO Calstock

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

164
Spills in 2025: 1,029.4
Recorded hours: 99.9%
Monitor operation: 5
Years listed

The reported spill count was 12 higher than in 2024. This compares event counts, not discharge volume.

Current status unknown

We do not have a live report for this outlet. Its annual spill records are shown below.

How it compares in 2025

Harewood Rd CSO Calstock recorded 164 spills in 2025. That is more than 99% of the 14,239 overflows in England with a reported figure, and ranks 24th nationally. Among South West Water overflows it ranks 15th of 1,357; the median South West Water overflow recorded 21 spills.

Group	Rank by spills	Median spills	Median hours
This outlet	–	164	1,029.4
England	24th of 14,239	11	22.3
South West Water	15th of 1,357	21	39.4

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 175 to 164 spills. The highest count was 189 in 2023 and the lowest was 152 in 2024. The monitor worked for less than 90% of 2021, so that count 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	164	1,029.4 hours	99.9%	Official data
2024	152	987.8 hours	98.6%	Official data
2023	189	1,137.1 hours	98.2%	Official data
2022	157	709.9 hours	100%	Official data
2021	175	1,000.9 hours	69%Low coverage	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: Storm overflow on the sewer network
Permit: 301833
Activity reference: A1
Grid reference: SX43636844
Waterbody ID: Unknown
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 “SO on sewer network”: storm overflow on the sewer network. The return places this overflow on the sewer network.

Where it is

The recorded position is about 0.4 km south-west of the Calstock reference point in the ONS built-up areas data.

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

Playing Fields Pscsoeo Calstock
South West Water · River Tamar (Estuarine)
Current status unknown

The Quay CSO Calstock
South West Water · River Tamar (Estuarine)
Current status unknown
Kelly Pscsoeo Calstock
South West Water · River Tamar (E)
Current status unknown
St Dominick STW So Callington
South West Water · River Tamar Estuary
Current status unknown

Questions about Harewood Rd CSO Calstock

Who operates Harewood Rd CSO Calstock?: South West Water is the operator named in the annual record. The permit reference is 301833.
Where does Harewood Rd CSO Calstock discharge?: The source names River Tamar (Estuarine) as the receiving water. This does not show how far a discharge travelled.
How many times did Harewood Rd CSO Calstock spill in 2025?: The 2025 return records 164 counted spill events and 1,029.4 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 99.9% of the reporting period, so the annual figures cover most of the year. They still do not measure discharge volume.
Is Harewood Rd CSO Calstock discharging right now?: This record is not matched to a company live feed, so we cannot show a current report. Only the annual figures are available for this outlet.
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 Harewood Rd CSO Calstock?: The annual return lists the asset type as “SO on sewer network”, which means storm overflow on the sewer network. The return places this overflow on the sewer network.
How does Harewood Rd CSO Calstock compare with other overflows?: Harewood Rd CSO Calstock recorded 164 spills in 2025. That is more than 99% of the 14,239 overflows in England with a reported figure, and ranks 24th nationally. Among South West Water overflows it ranks 15th of 1,357; the median South West Water overflow recorded 21 spills. 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.