Sewage Map

Portsmouth Harbour sewage map and spill data

36 storm overflows listed in the 2025 annual return name this water. All are operated by Southern Water. Check the latest company report for each outlet below.

36
Outlet records
262
Spills in 2025
545
Recorded hours
33
Linked to a live feed

2 records show monitor operation below 90%. Annual figures describe the whole of 2025, not today.

Official waterbody record ↗How spills are countedSearch the national map

Outlets on Portsmouth Harbour

Filter by the latest company report. The map follows the filters.

Filters apply to the map and list. Recent stops need a current report and a recorded stop time. They do not show whether water is safe.

Showing 10 of 36 outlets

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Most recorded spills in 2025

The highest 2025 counts among these outlets. A count is events, not volume or harm. Equal counts share a rank.

  1. 1
    Pier Road Southsea CSO - 108469

    Southern Water · monitor coverage 50.4%, below 90%

    43spills
  2. 2
    Gladys Avenue Portsmouth CSO - 108434

    Southern Water

    39spills
  3. 3
    North End Avenue Portsmouth CSO - 108773

    Southern Water

    31spills
  4. 4
    Fareham Road Gosport Outside 359 CSO - 108505

    Southern Water

    26spills
  5. 5
    Elmhurst Road Fareham CSO - 108425

    Southern Water

    19spills

Spills over time

The median outlet on Portsmouth Harbour recorded 3 spills in 2025, against 11 across England.

30 outlets have a comparable count for both 2024 and 2025, with the monitor working at least 90% of each year. 4 recorded more spills, 16 fewer and 10 the same. Together they went from 286 to 210 spills, a fall of 27%.

Largest rises from 2024 to 2025

YearOutlets with a countTotal spillsMedian per outletEngland median
202536262311
202436340419
2023323885.520
202232299313
2021323444.519

Earlier returns list fewer of these outlets, so totals are not comparable between years. The median per outlet and the like-for-like change are fairer comparisons. Counts are events, not volume.

All outlet records on Portsmouth Harbour

36 outlet records in alphabetical order. Each link opens the outlet page with its latest report and annual history.

Sources and dates

Outlet locations, waterbody links and spill figures come from the Environment Agency 2025 event duration monitoring annual return. The latest company reports come from each operator’s live feed and carry their own dates. Waterbody ID: GB580705140000. The official waterbody record is a source lookup; its classification is not imported here.

All sourcesHow the data worksReport pollution

Questions about Portsmouth Harbour

Which outlets are linked to Portsmouth Harbour?
The source links 36 outlet records to waterbody GB580705140000. The link comes from the annual return; it does not model where a discharge travelled.
How many spills were recorded for Portsmouth Harbour?
36 records report 262 spills in 2025 and 545 recorded hours. All listed records have a usable count. Outlets can discharge at the same time, so the hours are not the time the whole water was affected.
Who is responsible for the outlets on Portsmouth Harbour?
Southern Water operates every listed outlet. Contact the operator or the official pollution service if you see a problem in the water.
Which outlets on Portsmouth Harbour are linked to a live feed?
33 of the 36 records are matched to a monitor in a company live feed. A link does not mean the monitor is working now. Use the status filters above to see the latest report for each outlet, with its date. The rest show annual figures only.
How complete is the monitoring for Portsmouth Harbour?
2 of the listed records have monitor operation below 90% for 2025. Events can be missed when a monitor is not working, so low counts from those outlets may understate activity.
Does this show if Portsmouth Harbour is safe?
No. Event duration data does not measure bacteria, chemicals or current water quality. Use official local water-quality advice for that question.