Sewage Map

Crossness STW

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

13
Spills in 2025
84.8
Recorded hours
99.6%
Monitor operation
5
Years listed

The reported spill count was 17 lower than in 2024. This compares event counts, not discharge volume.

Current status unknown

Checking the latest monitor report…

Open official annual data ↗

How it compares in 2025

Crossness 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 Thames Water overflows it ranks 205th of 579; the median Thames Water overflow recorded 6 spills. On the Thames Middle waterbody it ranks 9th of 71.

GroupRank by spillsMedian spillsMedian hours
This outlet–1384.8
England6,413th of 14,2391122.3
Thames Water205th of 579620.9
Thames Middle9th of 7122.8

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

35202162022242023302024132025
From 2021 to 2025, the reported count went from 35 to 13 spills. The highest count was 35 in 2021 and the lowest was 6 in 2022. 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
20251384.8 hours99.6%Official data
202430232.6 hours100%Official data
202324232.1 hours100%Official data
2022654.7 hours35.4%Low coverageOfficial data
202135383.9 hours100%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
CSSA.0362
Activity reference
A2
Grid reference
TQ4857081130 and TQ4850081170
Waterbody ID
GB530603911402Official waterbody record ↗
Location source
Official annual grid reference
Location precision
About 1 metres
Location note
The source cell states 2 grid references. This marker uses the first stated reference.

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 3.7 km south of the Barking and Dagenham 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 Crossness STW

Who operates Crossness STW?
Thames Water is the operator named in the annual record. The permit reference is CSSA.0362.
Where does Crossness STW discharge?
The source names Thames Tidal as the receiving water. This does not show how far a discharge travelled.
How many times did Crossness STW spill in 2025?
The 2025 return records 13 counted spill events and 84.8 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 99.6% of the reporting period, so the annual figures cover most of the year. They still do not measure discharge volume.
Is Crossness 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 Crossness 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 Crossness STW compare with other overflows?
Crossness 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 Thames Water overflows it ranks 205th of 579; the median Thames Water overflow recorded 6 spills. On the Thames Middle waterbody it ranks 9th of 71. 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.