Sewage Map

Castle Ashby STW

Storm overflow operated by Anglian Water. The source names unnamed tributary Castle Ashby as the receiving water.

8
Spills in 2025
1.7
Recorded hours
100%
Monitor operation
5
Years listed

The reported spill count was 20 lower than in 2024. This compares event counts, not discharge volume.

Current status unknown

Checking the latest monitor report…

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How it compares in 2025

Castle Ashby STW recorded 8 spills in 2025. That is more than 42% of the 14,239 overflows in England with a reported figure, and ranks 7,797th nationally. Among Anglian Water overflows it ranks 579th of 1,438; the median Anglian Water overflow recorded 6 spills.

GroupRank by spillsMedian spillsMedian hours
This outlet–81.7
England7,797th of 14,2391122.3
Anglian Water579th of 1,438613.5

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

182021820228202328202482025
From 2021 to 2025, the reported count went from 18 to 8 spills. The highest count was 28 in 2024 and the lowest was 8 in 2022. The monitor worked for less than 90% of 2021, so that count may be low.Amber bars mark years when the monitor worked for less than 90% of the year.
YearSpillsDurationMonitor operationSource
202581.7 hours100%Official data
20242882.1 hours100%Official data
202382.3 hours100%Official data
2022824.3 hours100%Official data
202118402.3 hours20.7%Low coverageOfficial 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
Inlet storm overflow at a wastewater treatment works
Permit
AWNNF13072
Activity reference
A2
Grid reference
SP8592059860
Waterbody ID
GB105032045030Official 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 1.9 km west of the Grendon (North Northamptonshire) 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.

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Other outlet records nearby

Questions about Castle Ashby STW

Who operates Castle Ashby STW?
Anglian Water is the operator named in the annual record. The permit reference is AWNNF13072.
Where does Castle Ashby STW discharge?
The source names unnamed tributary Castle Ashby as the receiving water. This does not show how far a discharge travelled.
How many times did Castle Ashby STW spill in 2025?
The 2025 return records 8 counted spill events and 1.7 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 Castle Ashby 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 Castle Ashby 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 Castle Ashby STW compare with other overflows?
Castle Ashby STW recorded 8 spills in 2025. That is more than 42% of the 14,239 overflows in England with a reported figure, and ranks 7,797th nationally. Among Anglian Water overflows it ranks 579th of 1,438; the median Anglian Water overflow recorded 6 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.