Horning-Knackers Wood STW
Storm overflow operated by Anglian Water. The source names The River Ant as the receiving water.
- 13
- Spills in 2025
- 204
- Recorded hours
- 99.1%
- Monitor operation
- 5
- Years listed
The reported spill count was 190 lower than in 2024. This compares event counts, not discharge volume.
Checking the latest monitor report…
How it compares in 2025
Horning-Knackers Wood STW recorded 13 spills in 2025. That is more than 53% of the 14,239 overflows in England with a reported figure, and ranks 6,413th nationally. Among Anglian Water overflows it ranks 412th of 1,438; the median Anglian Water overflow recorded 6 spills. On the Ant (Dilham to R. Bure) waterbody it ranks 1st of 3.
| Group | Rank by spills | Median spills | Median hours |
|---|---|---|---|
| This outlet | – | 13 | 204 |
| England | 6,413th of 14,239 | 11 | 22.3 |
| Anglian Water | 412th of 1,438 | 6 | 13.5 |
| Ant (Dilham to R. Bure) | 1st of 3 | 3 | 7.2 |
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 | 13 | 204 hours | 99.1% | Official data |
| 2024 | 203 | 4,359.5 hours | 99.8% | Official data |
| 2023 | 91 | 1,747.8 hours | 100% | Official data |
| 2022 | 115 | 2,167 hours | 100% | Official data |
| 2021 | 166 | 3,180.3 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
- Anglian Water
- Outlet type
- Storm tank at a wastewater treatment works
- Permit
- AW4NF521
- Activity reference
- A2
- Grid reference
- TG3621018080
- Waterbody ID
- GB105034051330Official 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 2.2 km east of the Horning 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
- Ludham-Womack Staithe TpsCurrent status unknown
Anglian Water · unnamed tributary Womack Water
- Stalham-Mill Road TpsCurrent status unknown
Anglian Water · Stalham Dyke
- Stalham STWCurrent status unknown
Anglian Water · The River Ant & Tributary
- Halvergate-Marsh Rd SpCurrent status unknown
Anglian Water · Halvergate Fleet Dyke Marsh Dy
Questions about Horning-Knackers Wood STW
- Who operates Horning-Knackers Wood STW?
- Anglian Water is the operator named in the annual record. The permit reference is AW4NF521.
- Where does Horning-Knackers Wood STW discharge?
- The source names The River Ant as the receiving water. This does not show how far a discharge travelled.
- How many times did Horning-Knackers Wood STW spill in 2025?
- The 2025 return records 13 counted spill events and 204 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 99.1% of the reporting period, so the annual figures cover most of the year. They still do not measure discharge volume.
- Is Horning-Knackers Wood 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 Horning-Knackers Wood STW?
- 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 Horning-Knackers Wood STW compare with other overflows?
- Horning-Knackers Wood STW recorded 13 spills in 2025. That is more than 53% of the 14,239 overflows in England with a reported figure, and ranks 6,413th nationally. Among Anglian Water overflows it ranks 412th of 1,438; the median Anglian Water overflow recorded 6 spills. On the Ant (Dilham to R. Bure) waterbody it ranks 1st of 3. 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.