On 5 September 2026, The Guardian published reporting from Brighton beach documenting how routine sewage spills are reshaping when and where residents can safely swim along the East Sussex coast, with campaigners linking the issue to a national ranking that named South West Water as England's worst-performing water company on environmental damage The Guardian. A 75-year-old regular sea swimmer said that checking sewage-spill alerts had become as routine as checking the weather, while an open-water swim coach reported that pool swimmers are now refusing to enter the sea during summer over fears of illness The Guardian.
Key takeaways
- A sewage alert was issued twice at Brighton beach in August, and 158 alerts were recorded across the reporting area in 2025, according to public data cited by The Guardian The Guardian.
- Friends of the Earth ranked South West Water as having the worst environmental record in England in the week the Guardian visited Brighton The Guardian.
- Swimmers interviewed said they now treat checking for sewage spills as a normal part of planning a sea swim, comparable with checking the weather and tidal patterns The Guardian.
- Southern Water said Brighton's official bathing water is classified as "good" or "excellent" by the Environment Agency and that storm releases near the city have not occurred for four years, with overflows routed to its Peacehaven treatment works The Guardian.
What happened on the beach
Reporting on 5 September 2026 described Brighton as a focal point for frustration over coastal water quality during a summer of record-breaking heatwaves in England The Guardian. Jo Armstrong, 75, told the paper she had been unable to swim at her usual spot in nearby Seaford for the past week because the water was too polluted, and travelled to Brighton instead The Guardian. "There's a tiny bit of rain and then the sewage comes, I just don't understand it. It's extraordinary that we can't have clean beaches," she said The Guardian.
Hildi Mitchell, 55, who runs the Pool to Pier programme teaching pool swimmers to swim safely in open water, said pollution is now deterring people from entering the sea at all The Guardian. Greg Veros, 59, a long-term Brighton resident, said he had fallen ill after swimming in sewage-polluted water some years ago and now swims mostly at Brighton's outdoor pool The Guardian. Anna Field, 54, said she had arrived at the beach on several occasions and smelt sewage, although she noted this had been less common during the dry summer weather The Guardian.
What the utility said
A Southern Water spokesperson told the Guardian that Brightin's official bathing water is classified as "good" or "excellent" by the Environment Agency and pointed to a 30-metre-deep storm tunnel under the seafront capable of holding 150,000 tonnes of rainwater The Guardian. The spokesperson said there had not been a storm release close to Brighton for the last four years and that any storm overflows are passed down the coast to the company's state-of-the-art treatment works in Peacehaven The Guardian.
Specification read
The Guardian reports 158 sewage alerts across the area in 2025 and two further alerts at Brighton beach in August, but does not publish a design flow, BOD or COD figure for any affected works, so no source-linked m³/day or mg/L number can be extracted. The Peacehaven site described by Southern Water is presented as a "state-of-the-art treatment works" handling storm overflows from the Brighton catchment, and the 150,000-tonne stormwater storage tunnel is equivalent to roughly 150,000 m³ of wet-weather equalisation, a class of large coastal CSO tank for a population-equivalent range of roughly 200,000 to 400,000 residents (general industry range, not from the sources). A coastal interceptor of this scale typically runs screening → grit removal → primary settlement → biological stage (A2O, MBR or SBR) → tertiary filtration and UV or chlorine disinfection, with the August 2026 incident bearing most directly on the storm-overflow handling and disinfection side of that train. If your plant is a coastal municipal works sized at 50,000 to 200,000 m³/day on a combined sewer with intermittent storm surges and is under bathing-water compliance pressure, then the reported spill frequency and the operator's stated reliance on downstream transfer to Peacehaven are the operational signal to watch when you size storm equalisation and disinfection capacity. For a packaged inland equivalent sized to a small community, see the Underground Package Sewage Treatment Plant (WSZ Series) product page, and for design criteria on a comparable municipal train see the Package Sewage Treatment Plant Design Criteria: 2026 Engineering Guide. Operators comparing biological stages for similar loads can also review the Integrated Sewage Treatment category and the Municipal industry hub.
FAQ
What bathing-water classification applies to Brighton?
Southern Water told The Guardian that the official bathing water at Brighton is classified as "good" or "excellent" by the Environment Agency The Guardian. Classifications are set annually and can be downgraded after a poor season, so buyers specifying coastal plants should confirm the latest Environment Agency designation before sizing disinfection.
How many sewage alerts were recorded in 2025?
The Guardian cites public data showing 158 alerts across the reporting area in 2025 and two alerts at Brighton beach in August The Guardian. Spill counts are the standard KPI a buyer should request from any supplier quoting on a combined-sewer upgrade.
What is a typical storm-equalisation volume for a coastal interceptor of this size?
Southern Water describes a 150,000-tonne (about 150,000 m³) stormwater tunnel under Brighton's seafront The Guardian. General industry sizing for wet-weather equalisation is often 4 to 6 hours of average dry-weather flow for interceptor tunnels (general industry range, not from the sources), and the 2026 incident suggests buyers should treat the lower end of that range as a minimum.
Which treatment stages are most exposed when a coastal CSO spills?
When a combined sewer overflows, the screening, primary settlement and disinfection stages take the immediate load; the biological stage is protected by upstream equalisation. For a packaged inland equivalent sized to a small community, the Underground Package Sewage Treatment Plant (WSZ Series) product page lists the screening to disinfection chain and is a useful reference when scoping.
