Local · Portsmouth

Sewage discharges and Southsea East bathing water

One of Southsea's two bathing waters is officially classified "Poor", and storm overflows discharged into Portsmouth Harbour 124 times in the most recent reporting year. A £170m investment programme is under way.

View shareable visual summaries
Public attention
High

A sustained, multi-year campaign by the Portsmouth South MP, recurring local media coverage, and consistently high engagement on local social media.

Measured scale
Localised

Serious and well-evidenced, but geographically concentrated: Southsea East is classified Poor while Eastney, the other Southsea-area sampling point, is classified Good. Affects bathing and harbour water users rather than the whole population directly.

Direction of travel
Too early to tell

The £170m programme has delivered at least one named local fix, but the Poor classification has persisted and no post-investment improvement in classification has yet been recorded.

Southsea bathing water

Poor annual classification and recurring pollution warnings, but no sewage debris recorded at this monitoring site during the stated assessment period.

Southsea East
Eastney
34
pollution risk warnings, 2025 season
91%
of visits where litter was observed, 2022-2025
Not noted
sewage debris at this site, 2022-2025
Named risks
Tide · Rainfall · Urban drainage · Occasional Canoe Lake discharge
What these figures do and do not show

Pollution risk warnings are short-term forecasts issued when conditions make pollution likely. They are not measurements that a discharge occurred. "Sewage debris not noted" refers to visual assessment at this monitoring point and does not rule out discharges elsewhere in the harbour.

The evidence does not support saying that raw sewage is dumped at Southsea daily, or that the beach is never safe to swim. It equally does not support saying the water is fine: the classification is Poor and there were 34 pollution risk warnings in 2025.

Environment Agency — Southsea East bathing water profile → · 2025 season

Who can change this

Southern Water, regulated by the Environment Agency and Ofwat

Next decision

The next Environment Agency bathing water classification

What you can do

Report a pollution incident to the Environment Agency's 24-hour line; raise systemic concerns with Ofwat and your MP

Poor
Southsea East bathing water
2025 season classification
Third consecutive Poor year
Good
Eastney bathing water
2025 season classification
34
Pollution risk warnings, Southsea East
2025 season
Forecasts, not confirmed discharges
Not noted
Sewage debris at Southsea East
EA assessment period 2022-2025
Litter observed on 91% of visits
124 spills / 234 hours
Portsmouth Harbour spills
2025 reporting year
Across 12 Southern Water outfalls
£170m
Investment programme
Three Harbours Partnership, ongoing
Signal — why this is here

Among the most consistently raised local environmental issues by residents, campaigners and the Portsmouth South MP.

Public and political discussion indicates what people are raising. It is not evidence that a claim is true.

Evidence — what has happened

Verified facts

The Environment Agency classifies Southsea East (Pyramids to South Parade Pier) as "Poor" for the 2025 season, its third consecutive Poor year; Eastney is "Good". The site received 34 pollution risk warnings during 2025. Over the Environment Agency's 2022-2025 assessment period, sewage debris was NOT noted at this monitoring site, while litter was observed on 91% of visits; the named short-term risks are tide, rainfall, urban drainage and occasional Canoe Lake discharge. Rivers Trust aggregation of Environment Agency Event Duration Monitoring records 124 storm overflow spills totalling 234 hours across 12 Southern Water outfalls in Portsmouth Harbour, and 11 spills totalling 24 hours across 2 Langstone Harbour outfalls, in the 2025 reporting year.
Has it worked?

Not yet demonstrable. Southsea East remains classified Poor for a third consecutive season and received 34 pollution warnings in 2025. No published site-level spill data yet shows a sustained fall attributable to the programme. The Environment Agency did not, however, note sewage debris at the Southsea East monitoring site across 2022-2025 — the picture is worse than "fine" and better than "raw sewage daily".
Full detail — why it matters, who else is involved, what is being done
Why it matters. Affects whether the sea is safe to swim in at a major public beach, the ecology of two harbours, and the city's visitor economy. Bathing water classification is a statutory public-health measure, not a reputational one.
Why it happens. Southern Water's own explanation: many Portsmouth-area sewers are combined systems carrying rainwater and sewage in the same pipe. In heavy rain the combined flow exceeds pipe or treatment capacity, and storm overflows act as an engineered relief valve to stop sewage backing up into homes. Rainwater misconnected into the foul network is a named contributor.
Where. Southsea East seafront; Portsmouth Harbour and Langstone Harbour outfalls, including Cosham and Stamshaw.
What is being done. Southern Water's £170m Three Harbours Partnership covers Portsmouth, Langstone and Chichester Harbours: sustainable drainage, smart water butts, disconnecting downpipes from foul sewers, and pumping station upgrades. A decades-old sewer bottleneck under Stanley Road, Stamshaw has reportedly been removed. Cost: £170m (Southern Water investment, part of a wider £1.5bn Clean Rivers and Seas Plan)
Everyone involved.
  • •Southern Water — Owns and operates the network — the decisive lever
  • •Environment Agency — Sets and enforces discharge permits, monitors bathing water, prosecutes
  • •Ofwat — Sets what the company may spend and charge; levies performance penalties
  • •Portsmouth City Council — Limited — planning and highway drainage decisions affecting surface-water load
What is still not known.
  • •No published site-by-site delivery timetable for the remaining worst outfalls.
  • •EDM records the duration of a discharge, not its volume or pollutant load.
  • •The Environment Agency has not published a site-level explanation of why Southsea East has remained Poor for three consecutive seasons.
  • •Pollution risk warnings are forecasts, so the number issued is not a count of discharges that occurred.
Full sewage evidence and charts →Is the sea "full of sewage"? — claim tested →
Sources & methodology (4) · last verified 2026-08-26

What could be done, and what it would cost

Full action plan →

UK Stat Pack's own analysis — not Portsmouth City Council or government policy. Each item states what is officially happening, if anything.

A public, dated delivery timetable for the remaining worst Portsmouth/Langstone sewage outfalls

Underway
Estimated cost
No new cost — this is a transparency/reporting ask on an already-funded (£170m) programme, not a new spending request.
Funding route
Already funded — Southern Water's existing Three Harbours Partnership / Clean Rivers and Seas Plan.
Timescale
Short-term (1–3 yrs)
Why it might work, and the trade-offs

The programme has already delivered at least one concrete, named fix — the ask here is transparency and pace, not a new mechanism.

Trade-offs. None significant — this is a transparency ask on an existing programme rather than a new intervention with its own trade-offs.

How we would know it worked. A published site-by-site timetable existing at all; Spill count/hours falling at the named worst outfalls year-on-year

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