What's happened, and what next
What happened
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.
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.
What's 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.
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".
What happens next
The next Environment Agency bathing-water classification, and the next annual EDM spill return.
Cost
£170m (Southern Water investment, part of a wider £1.5bn Clean Rivers and Seas Plan)