Around 245,000 people have been warned that their drinking water has been contaminated with bacteria which could cause infections.
Coliform bacteria was discovered in the drinking water supplied to Chemnitz in east Germany.
Some of the city’s residents have been urgently told not to drink any tap water unless it has been boiled.
They also must not brush their teeth with drinking water or rinse fruit and vegetables with it.
This warning applies to people with weakened immune systems, who could develop diarrhoea, intestinal infections or urinary tract infections from the contaminated water.
The water company, eins energie, stressed that there are no health risks for the public.
The coliform bacteria was discovered by the city’s health department and eins energie after routine inspection revealed something suspicious, prompting further testing.
The bacteria are common in soil and lakes as well as the intestines of humans and animals.
Health officials say they usually don’t make people sick, but if found in drinking water, can indicate that other disease-causing organisms may be lurking around.
Eins energie explained: ‘As the results now available to us after sequencing the samples show, the contaminants are coliform bacteria, which are also found in the environment.’
According to the German newspaper Freie Presse, irregularities were detected in locations in the western part of the city.
The cause of the contamination is still unclear, but the company say it has ramped up efforts to protect customers.
Eins energie added: ‘Measures already initiated also include increased and closely monitored sampling, network flushing, and further disinfection measures.
‘Through close monitoring, intensive efforts are being made to identify and eliminate the source of the contamination.
‘According to current assessments, these measures will take several more days. As soon as new information becomes available, we will inform you immediately.’
The warning comes a year after a different bacterium wreaked havoc in the UK.
Over 20 people on the south coast of Devon became sick with a diarrhoea parasite after they drank contaminated tap water.
South West Water said tests showed ‘small traces’ of cryptosporidium had been found, with the issue affecting people in Alston and Brixham on the south coast of Devon.
Over 2,000 households were warned they should boil water and leave it to cool before using it to make sure the bug is killed if present.
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