People in Hastings, Minnesota, are under a boil water advisory following the detection of E. coli in the city's public water system.
The alert was issued on Saturday afternoon. While the bacteria was "isolated to one section" of the system, a large swath of the city is being told to boil its water or "use a safe alternative source" such as bottled water.
The affected areas are within the red boundary seen on the map below:
"Boiled or bottled water should be used for drinking, making ice, brushing teeth, and food preparation until further notice," the city's alert says, adding that "boiling kills bacteria and other organisms in water."
Local authorities were apparently flooded with emergency calls after the advisory was issued; a Saturday night update asked citizens to refrain from calling 911 "unless you have an actual medical or safety emergency!"
While it's not exactly clear how E. coli got into the water system, the advisory points out that the bacteria can be caused by "human or animal wastes."
The city says it's treating the contaminated section with chlorine, and that it expects the problem to be resolved "within 3-5 days."
For more info about E. coli, symptoms, and prevention, check out this page from the Centers for Disease Control.