Southern Water data highlights bathing water quality standard of ‘Poor’

it’s a serious question and also the sign of our times. Even though a vast amount of money is given to water companies, people are getting sick using the River Itchen as a leisure facility, even if you using an oar or paddle there is a chance you could be ill for a few days.

Southampton River Rights are very proactive when it comes to the quality of water in the river, one of the planet’s rare chalk streams, yet somehow it is low on the priorities of people who operate either beside it, or charged with putting “clean” water into it.

Their recent press release [The Itchen in Southampton Public Health Risk and Faecal Pathogen Indicator Data (E coli & Enterococci) recently obtained from Southern Water August 2026] began with some recent social media comments concerning illness after swimming in the Itchen in Southampton include,

“My daughter and a friend got sick after swimming at Mansbridge during the very hot week recently and the same happened to my eldest after paddle boarding and jumping in further up the river”

 “We went paddle boarding last Sunday, my two young boys swam in the water, by Monday they were extremely sick”

“My daughter and her friend were hospitalised after swimming in the river the same week after becoming very unwell” [symptoms included severe gastroenteritis, an eye infection and irregular heartbeat] “No public signage with warnings and no prior knowledge of any issues!”

Supporters of the River Itchen gathering for an awareness event at Mansbridge

Here is the press release from Gavin Millar, and Southampton River Rights

Last year, Southern Water commissioned a series of Upper Itchen Estuary and Mansbridge E. coli and Enterococci water-quality tests. 

Southern Water’s Director of Wastewater Operations said that Southern Water would consider publishing the results. 

No publication followed. I therefore submitted an Environmental Information Regulations (EIR) request in early July. The data, 474 test results from 8 sites across 10 Aug to Dec sampling days, arrived four weeks later. 

The single chart below is enough to reveal the scale of extraordinarily high E coli contamination - appearing significantly worse than the results obtained by Friends of the Itchen Estuary, whose 2024 testing was limited to levels of below 10,000 cfu/100ml with fewer samples.

Southern Water’s Enterococci test result values were also extremely high.

Southern Water’s data indicates that every Itchen Estuary location tested for Southern Water would rate an Environment Agency bathing water quality standard of ‘Poor’, which means that E. coli is above 500 cfu/100ml and/or Enterococci is above 185 cfu/100ml for more than 10% of samples – shown in simplified form in the chart as a red line ‘safe’ upper limit for E coli.

A slightly different standard applies to freshwater. 

Nevertheless, water quality at the one freshwater location tested (The Old Mansbridge) also rates as ‘Poor.’

Footnotes:

Five Southern Water E coli test results exceeded the chart scale cut off level of 40,000 cfu/100ml – set at 80times the chart’s ‘safe’ upper limit for E coli! 

Previous work by Friends of the Itchen Estuary has shown that Itchen Estuary faecal pathogen contamination is a 24/7 x 365 days a year issue with the primary source being Portswood Sewage Works continuously flowing sewage effluent. 

The contribution from storm overflows is minor by comparison.

*cfu (colony forming units) /100ml is a water quality measure of bacterial levels. Levels of two bacteria, E coli and Enterococci, are regarded as indicators of a broad range of faecal pathogens including Salmonella, Campylobacter, Clostridium, Norovirus and more.

For more information visit

https://www.southamptonriverrights.com/

https://www.facebook.com/groups/719042875584402/

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