The owner of South West Water has warned that global warming could increase the risk of outbreaks of a parasitic worm which causes diarrhoea and vomiting in south Devon.
In its annual report published this week, Pennon Group said “moderate and significant increases in average and maximum temperatures” could pose “risks to water quality and water treatment”, including the cryptosporidium parasite.
The parasite, which is spread through faeces, causes cryptosporidiosis, which often causes fever, vomiting and diarrhea.
The Devon outbreak has thrust the quality of Britain’s water into the spotlight after a years-long investigation into the amount of wastewater dumped into the country’s rivers and seas. It has also become an election issue, with the Conservative party promising in its manifesto on Tuesday to ban executive bonuses if water companies “commit serious criminal breaches” and to invest in repairing rivers.
Around 17,000 South West Water domestic customers near the seaside town of Brixham in south Devon were advised last month to boil tap water before drinking it after more than 100 people reported symptoms.
Pennon’s report noted that global warming will increase the likelihood of flooding from rain and rising sea levels, as well as more heat waves and storms, raising costs.
It also lists a series of risks to water quality, including “odour, discoloration, dissolved organic matter and cryptosporidium” as well as “increased microbial growth and survival” and the rise of invasive species, all of which would require costly maintenance and treatment to resolve.
Paul Johnston of Greenpeace Research Laboratories said water companies should shift money away from shareholder dividends and executive bonuses and towards building resilience.
“Extreme temperatures increase the likelihood that toxic algae and pathogenic parasites will emerge in water sources and enter our water supplies,” he said. “This is a significant risk, but it would be disingenuous to blame it all on climate change. The risk stems primarily from our shoddy water supply and distribution systems that have suffered from years of underinvestment by water companies.”
South West Water said it had begun treating tanks in the village of Boohay with ultraviolet light to kill the microbes following the recent Cryptosporidium outbreak, after previously treating tanks in nearby Hillhead with ultraviolet light.
The company also cleaned the pipes using “ice pigging,” which involves rinsing the pipes and using a slurry of ice and water to push out dirt.
Before Parliament was dissolved ahead of the general election, MPs’ Environment, Food and Rural Affairs Select Committee wrote to Pennon chief executive Susan Davie, asking her to appear before the committee to answer questions about the outbreak.
It is unclear whether the new committee will consider the request after the July 4 election, but Mr Davie is likely to face questions about his pay. Despite giving up his 2023 annual bonus in response to outrage over the sewage dumping, his total pay has increased by £300,000 as share-based awards from 2021 have been locked in.
