Cattal/STW
Storm overflow operated by Yorkshire Water. The source names River Nidd as the receiving water.
- 28
- Spills in 2025
- 219.5
- Recorded hours
- 100%
- Monitor operation
- 6
- Years listed
The reported spill count was 4 lower than in 2024. This compares event counts, not discharge volume.
Checking the latest monitor report…
How it compares in 2025
Cattal/STW recorded 28 spills in 2025. That is more than 72% of the 14,239 overflows in England with a reported figure, and ranks 3,771st nationally. Among Yorkshire Water overflows it ranks 729th of 2,176; the median Yorkshire Water overflow recorded 16 spills. On the River Nidd from Crimple Beck to River Ouse waterbody it ranks 5th of 10.
| Group | Rank by spills | Median spills | Median hours |
|---|---|---|---|
| This outlet | – | 28 | 219.5 |
| England | 3,771st of 14,239 | 11 | 22.3 |
| Yorkshire Water | 729th of 2,176 | 16 | 37.8 |
| River Nidd from Crimple Beck to River Ouse | 5th of 10 | 27 | 117.8 |
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 | 28 | 219.5 hours | 100% | Official data |
| 2024 | 32 | 202 hours | 100% | Official data |
| 2023 | 41 | 484.5 hours | 99.9% | Official data |
| 2022 | 19 | 123.5 hours | 100% | Official data |
| 2021 | 43 | 254.3 hours | 100% | Official data |
| 2020 | 18 | 285.9 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
- Yorkshire Water
- Outlet type
- Inlet storm overflow at a wastewater treatment works
- Permit
- 27/21/0166
- Activity reference
- 2
- Grid reference
- SE4465053990
- Waterbody ID
- GB104027068292Official 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 “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 2.2 km north-west of the Tockwith reference point in the ONS built-up areas data.
Area and water pages
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
- Tockwith/STWCurrent status unknown
Yorkshire Water · Fleet Beck
- Hunsingore/STWCurrent status unknown
Yorkshire Water · An Unnamed Tributary of Nidd
- Chapel Street York/CSOCurrent status unknown
Yorkshire Water · Kirk Hammerton Beck
- Kirk Hammerton/STWCurrent status unknown
Yorkshire Water · River Nidd
Questions about Cattal/STW
- Who operates Cattal/STW?
- Yorkshire Water is the operator named in the annual record. The permit reference is 27/21/0166.
- Where does Cattal/STW discharge?
- The source names River Nidd as the receiving water. This does not show how far a discharge travelled.
- How many times did Cattal/STW spill in 2025?
- The 2025 return records 28 counted spill events and 219.5 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 Cattal/STW 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 Cattal/STW?
- 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 Cattal/STW compare with other overflows?
- Cattal/STW recorded 28 spills in 2025. That is more than 72% of the 14,239 overflows in England with a reported figure, and ranks 3,771st nationally. Among Yorkshire Water overflows it ranks 729th of 2,176; the median Yorkshire Water overflow recorded 16 spills. On the River Nidd from Crimple Beck to River Ouse waterbody it ranks 5th 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.