Sewage Map

Deephams STW

Storm overflow operated by Thames Water. The source names Salmon Brook as the receiving water.

6
Spills in 2025
55.3
Recorded hours
92.6%
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

Deephams STW recorded 6 spills in 2025. That is more than 37% of the 14,239 overflows in England with a reported figure, and ranks 8,498th nationally. Among Thames Water overflows it ranks 287th of 579; the median Thames Water overflow recorded 6 spills.

GroupRank by spillsMedian spillsMedian hours
This outlet–655.3
England8,498th of 14,2391122.3
Thames Water287th of 579620.9

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

27202115202218202326202462025
From 2021 to 2025, the reported count went from 27 to 6 spills. The highest count was 27 in 2021 and the lowest was 6 in 2025. The monitor worked for less than 90% of 2022, so that count may be low.Amber bars mark years when the monitor worked for less than 90% of the year.
YearSpillsDurationMonitor operationSource
2025655.3 hours92.6%Official data
202426230.8 hours100%Official data
202318110.8 hours99.8%Official data
202215120.6 hours67.6%Low coverageOfficial data
202127183.5 hours91.9%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
Thames Water
Outlet type
Storm tank at a wastewater treatment works
Permit
CNTD.0072
Activity reference
A2
Grid reference
TQ3566093150
Waterbody ID
GB106038027910Official 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 4.8 km south-east of the Enfield 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

Questions about Deephams STW

Who operates Deephams STW?
Thames Water is the operator named in the annual record. The permit reference is CNTD.0072.
Where does Deephams STW discharge?
The source names Salmon Brook as the receiving water. This does not show how far a discharge travelled.
How many times did Deephams STW spill in 2025?
The 2025 return records 6 counted spill events and 55.3 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 92.6% of the reporting period, so the annual figures cover most of the year. They still do not measure discharge volume.
Is Deephams 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 Deephams 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 Deephams STW compare with other overflows?
Deephams STW recorded 6 spills in 2025. That is more than 37% of the 14,239 overflows in England with a reported figure, and ranks 8,498th nationally. Among Thames Water overflows it ranks 287th of 579; the median Thames 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.