Tap water in thousands of homes could be contaminated by E. coli after tests found 443 postcodes in Surrey and Kent could be affected the potentially deadly bacteria, officials say.
People living in Oxted, Redhill, Limpsfield, Godstone and Sevenoaks are being advised to boil their drinking water after the problem was uncovered.
SES Water said it had “teams working to investigate the problem” while they carry out further tests to “confirm the scale of any contamination”.
It also issued a list of the 443 postcodes affected.
“We are very sorry to everyone who is being affected,” a SES spokesperson said.
“Everything possible is being done to do further testing and we will keep everyone informed.”
They added that they were supporting the “most vulnerable customers as a priority”.
The NHS says E.coli does not usually cause any problems while it is living in the gut, but that if the bacteria contaminates areas of vulnerability such as wounds, infection can occur.
Those considered most at risk if they do become infected include the elderly, people with urinary catheterisation and those suffering dehydration, prostate problems, gall bladder or kidney stones, open wounds or ulcers, or with long-term conditions such as COPD, bronchitis or diabetes.
While most cases are mild, some strains of E. coli can cause severe symptoms and even life-threatening complications, which can lead to kidney failure and death.
Officials reminded people in the affected areas to let the boiled water cool before using it for drinking, preparing food or cleaning their teeth and added the same process should be followed for water given to pets.
“Boiled water can be kept in the fridge, and should be covered and used within 24 hours,” a spokesperson said.