Clammerclough CSO
Storm overflow operated by United Utilities. The source names River Croal as the receiving water.
- 93
- Spills in 2025
- 271.3
- Recorded hours
- 99.9%
- Monitor operation
- 2
- Years listed
The reported spill count was 16 lower than in 2024. This compares event counts, not discharge volume.
Checking the latest monitor report…
How it compares in 2025
Clammerclough CSO recorded 93 spills in 2025. That is more than 97% of the 14,239 overflows in England with a reported figure, and ranks 321st nationally. Among United Utilities overflows it ranks 92nd of 2,270; the median United Utilities overflow recorded 15 spills. On the Irwell (Croal to Irk) waterbody it ranks 1st of 56.
| Group | Rank by spills | Median spills | Median hours |
|---|---|---|---|
| This outlet | – | 93 | 271.3 |
| England | 321st of 14,239 | 11 | 22.3 |
| United Utilities | 92nd of 2,270 | 15 | 29.1 |
| Irwell (Croal to Irk) | 1st of 56 | 16 | 28 |
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 | 93 | 271.3 hours | 99.9% | Official data |
| 2024 | 109 | 335.4 hours | 99.9% | 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
- United Utilities
- Outlet type
- Storm overflow on the sewer network
- Permit
- 016993549
- Activity reference
- A1
- Grid reference
- SD7473006060
- Waterbody ID
- GB112069061451Official waterbody record ↗
- Location source
- Official annual grid reference
- Location precision
- About 1 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.
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 1.1 km north-west of the Kearsley reference point in the ONS built-up areas data.
Area and water pages
- Wardley area →
- Clifton (Salford) area →
- Swinton (Salford) area →
- Whitefield area →
- Pendlebury area →
- Salford area →
- Prestwich area →
- Rhodes area →
- Simister area →
- Worsley area →
- Eccles (Salford) area →
- Radcliffe area →
- Walkden area →
- Kearsley area →
- Little Hulton area →
- Farnworth area →
- Little Lever area →
- Astley area →
- Tyldesley area →
- Westhoughton area →
- Bury (Bury) area →
- Higher Folds area →
- Wingates area →
- Atherton area →
- Hunger Hill (Bolton) area →
- Chew Moor area →
- Ainsworth area →
- Bolton (Bolton) area →
- Irwell (Croal to Irk) 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
- Prestolee PSCurrent status unknown
United Utilities · River Irwell
- Moses Gate Country Park CSO (073I5)Current status unknown
United Utilities · River Croal
- Ginger Fold CSOCurrent status unknown
United Utilities · River Croal
- Fern Street CSOCurrent status unknown
United Utilities · River Croal
Questions about Clammerclough CSO
- Who operates Clammerclough CSO?
- United Utilities is the operator named in the annual record. The permit reference is 016993549.
- Where does Clammerclough CSO discharge?
- The source names River Croal as the receiving water. This does not show how far a discharge travelled.
- How many times did Clammerclough CSO spill in 2025?
- The 2025 return records 93 counted spill events and 271.3 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 99.9% of the reporting period, so the annual figures cover most of the year. They still do not measure discharge volume.
- Is Clammerclough CSO 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 1 metres. It shows the recorded outlet position, not the extent of any discharge.
- What kind of outlet is Clammerclough CSO?
- 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 Clammerclough CSO compare with other overflows?
- Clammerclough CSO recorded 93 spills in 2025. That is more than 97% of the 14,239 overflows in England with a reported figure, and ranks 321st nationally. Among United Utilities overflows it ranks 92nd of 2,270; the median United Utilities overflow recorded 15 spills. On the Irwell (Croal to Irk) waterbody it ranks 1st of 56. 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.