Darley/STW, Yorkshire Water (27/21/0205 · A2 · YWS00249)
Storm overflow operated by Yorkshire Water. The source names Tributary of River Nidd as the receiving water.
- 97
- Spills in 2025
- 1,490
- Recorded hours
- 100%
- Monitor operation
- 6
- Years listed
The reported spill count was 49 lower than in 2024. This compares event counts, not discharge volume.
Checking the latest monitor report…
How it compares in 2025
Darley/STW, Yorkshire Water (27/21/0205 · A2 · YWS00249) recorded 97 spills in 2025. That is more than 97% of the 14,239 overflows in England with a reported figure, and ranks 281st nationally. Among Yorkshire Water overflows it ranks 37th of 2,176; the median Yorkshire Water overflow recorded 16 spills. On the Nidd from Ashfoldside Beck to Birstwith waterbody it ranks 1st of 9.
| Group | Rank by spills | Median spills | Median hours |
|---|---|---|---|
| This outlet | – | 97 | 1,490 |
| England | 281st of 14,239 | 11 | 22.3 |
| Yorkshire Water | 37th of 2,176 | 16 | 37.8 |
| Nidd from Ashfoldside Beck to Birstwith | 1st of 9 | 38 | 247.8 |
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 | 97 | 1,490 hours | 100% | Official data |
| 2024 | 146 | 2,260 hours | 100% | Official data |
| 2023 | 131 | 2,207.5 hours | 99.8% | Official data |
| 2022 | 77 | 725.7 hours | 97.7% | Official data |
| 2021 | 84 | 884.8 hours | 99.3% | Official data |
| 2020 | 123 | 2,235.2 hours | 97.6% | 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
- Storm tank at a wastewater treatment works
- Permit
- 27/21/0205
- Activity reference
- A2
- Grid reference
- SE2118259656
- Waterbody ID
- GB104027068295Official 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 “Storm tank at WwTW”: storm tank at a wastewater treatment works. The overflow comes from storm storage at a treatment 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 1.1 km east of the Darley 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
- Darley/STWCurrent status unknown
Yorkshire Water · Tributary of River Nidd
- Darley Head/CSOCurrent status unknown
Yorkshire Water · Darley Beck
- Dacre Banks/CSOCurrent status unknown
Yorkshire Water · River Nidd
- Summerbridge/CSOCurrent status unknown
Yorkshire Water · River Niidd
Questions about Darley/STW, Yorkshire Water (27/21/0205 · A2 · YWS00249)
- Who operates Darley/STW, Yorkshire Water (27/21/0205 · A2 · YWS00249)?
- Yorkshire Water is the operator named in the annual record. The permit reference is 27/21/0205.
- Where does Darley/STW, Yorkshire Water (27/21/0205 · A2 · YWS00249) discharge?
- The source names Tributary of River Nidd as the receiving water. This does not show how far a discharge travelled.
- How many times did Darley/STW, Yorkshire Water (27/21/0205 · A2 · YWS00249) spill in 2025?
- The 2025 return records 97 counted spill events and 1,490 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 Darley/STW, Yorkshire Water (27/21/0205 · A2 · YWS00249) 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 Darley/STW, Yorkshire Water (27/21/0205 · A2 · YWS00249)?
- The annual return lists the asset type as “Storm tank at WwTW”, which means storm tank at a wastewater treatment works. The overflow comes from storm storage at a treatment works.
- How does Darley/STW, Yorkshire Water (27/21/0205 · A2 · YWS00249) compare with other overflows?
- Darley/STW, Yorkshire Water (27/21/0205 · A2 · YWS00249) recorded 97 spills in 2025. That is more than 97% of the 14,239 overflows in England with a reported figure, and ranks 281st nationally. Among Yorkshire Water overflows it ranks 37th of 2,176; the median Yorkshire Water overflow recorded 16 spills. On the Nidd from Ashfoldside Beck to Birstwith waterbody it ranks 1st of 9. 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.