St Merryn CSO St Merryn
Storm overflow operated by South West Water. The source names Mother Iveys Bay (C) as the receiving water.
- 107
- Spills in 2025
- 1,381
- Recorded hours
- 100%
- Monitor operation
- 5
- Years listed
The reported spill count was 14 lower than in 2024. This compares event counts, not discharge volume.
Checking the latest monitor report…
How it compares in 2025
St Merryn CSO St Merryn recorded 107 spills in 2025. That is more than 98% of the 14,239 overflows in England with a reported figure, and ranks 195th nationally. Among South West Water overflows it ranks 78th of 1,357; the median South West Water overflow recorded 21 spills.
| Group | Rank by spills | Median spills | Median hours |
|---|---|---|---|
| This outlet | – | 107 | 1,381 |
| England | 195th of 14,239 | 11 | 22.3 |
| South West Water | 78th 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
| Year | Spills | Duration | Monitor operation | Source |
|---|---|---|---|---|
| 2025 | 107 | 1,381 hours | 100% | Official data |
| 2024 | 121 | 1,822.2 hours | 100% | Official data |
| 2023 | 133 | 1,852 hours | 96.9% | Official data |
| 2022 | 68 | 740.9 hours | 94% | Official data |
| 2021 | 53 | 617.8 hours | 96% | 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
- 300592
- Activity reference
- A1
- Grid reference
- SW86847607
- 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 1.9 km north of the Constantine Bay reference point in the ONS built-up areas data.
Designated bathing waters within 3 km in a straight line:
Distance does not show that water from this outlet reaches a bathing water. Check the official bathing-water profile for its classification and advice.
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
- Trehembourne SPS Pscsoeo St MerrynCurrent status unknown
South West Water · Treyarnon Stream
- Watergate SPS Pscsoeo Watergate BayCurrent status unknown
South West Water · Stream/ATLANTIC Ocean (S)
- Towan Head SPS Pscsoeo NewquayCurrent status unknown
South West Water · Atlantic Ocean(T)
- Gusti Veor CSO NewquayCurrent status unknown
South West Water · Unnamed Ditch,TRENANCE Lake(S)
Questions about St Merryn CSO St Merryn
- Who operates St Merryn CSO St Merryn?
- South West Water is the operator named in the annual record. The permit reference is 300592.
- Where does St Merryn CSO St Merryn discharge?
- The source names Mother Iveys Bay (C) as the receiving water. This does not show how far a discharge travelled.
- How many times did St Merryn CSO St Merryn spill in 2025?
- The 2025 return records 107 counted spill events and 1,381 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 100% of the reporting period, so the annual figures cover most of the year. They still do not measure discharge volume.
- Is St Merryn CSO St Merryn 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 St Merryn CSO St Merryn?
- 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 St Merryn CSO St Merryn compare with other overflows?
- St Merryn CSO St Merryn recorded 107 spills in 2025. That is more than 98% of the 14,239 overflows in England with a reported figure, and ranks 195th nationally. Among South West Water overflows it ranks 78th 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.