Thornham Inlet CEO - 115371
Storm overflow operated by Southern Water. The source names Chichester Hbr via Little Deep as the receiving water.
- 12
- Spills in 2025
- 118.6
- Recorded hours
- 100%
- Monitor operation
- 2
- Years listed
The reported spill count was 6 higher than in 2024. This compares event counts, not discharge volume.
Checking the latest monitor report…
How it compares in 2025
Thornham Inlet CEO - 115371 recorded 12 spills in 2025. That is more than 51% of the 14,239 overflows in England with a reported figure, and ranks 6,643rd nationally. Among Southern Water overflows it ranks 381st of 975; the median Southern Water overflow recorded 7 spills. On the Great Deep waterbody it ranks 2nd of 3.
| Group | Rank by spills | Median spills | Median hours |
|---|---|---|---|
| This outlet | – | 12 | 118.6 |
| England | 6,643rd of 14,239 | 11 | 22.3 |
| Southern Water | 381st of 975 | 7 | 17 |
| Great Deep | 2nd of 3 | 12 | 118.6 |
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 | 12 | 118.6 hours | 100% | Official data |
| 2024 | 6 | 52 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
- Southern Water
- Outlet type
- Inlet storm overflow at a wastewater treatment works
- Permit
- W00354
- Activity reference
- Storm
- Grid reference
- SU7582004730
- Waterbody ID
- GB610070074000Official 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 source name includes CEO, which Southern Water defines as Combined Emergency Overflow. The name and the listed type are separate source fields, so the name does not describe the layout of the site. Southern Water flow and spill reporting glossary ↗
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 1.7 km south-west of the Southbourne 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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Questions about Thornham Inlet CEO - 115371
- Who operates Thornham Inlet CEO - 115371?
- Southern Water is the operator named in the annual record. The permit reference is W00354.
- Where does Thornham Inlet CEO - 115371 discharge?
- The source names Chichester Hbr via Little Deep as the receiving water. This does not show how far a discharge travelled.
- How many times did Thornham Inlet CEO - 115371 spill in 2025?
- The 2025 return records 12 counted spill events and 118.6 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 Thornham Inlet CEO - 115371 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 Thornham Inlet CEO - 115371?
- 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. The source name includes CEO, which Southern Water defines as Combined Emergency Overflow. The name and the listed type are separate source fields.
- How does Thornham Inlet CEO - 115371 compare with other overflows?
- Thornham Inlet CEO - 115371 recorded 12 spills in 2025. That is more than 51% of the 14,239 overflows in England with a reported figure, and ranks 6,643rd nationally. Among Southern Water overflows it ranks 381st of 975; the median Southern Water overflow recorded 7 spills. On the Great Deep waterbody it ranks 2nd 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.