Residents of Hastings were advised Saturday to boil their water after E. coli bacteria were found in the city’s public water system.

The bacteria is “isolated to one section of our system,” the city said in an advisory, offering a detailed map of the contaminated area. Many large properties, including Regina Hospital, Allina Clinic, the YMCA and Hastings Middle School are NOT affected, it said.

Those in the affected area are advised to “bring all water to a full, rolling boil, let it boil for one minute or longer, and let it cool before using, or use bottled water.”

“Boiled or bottled water should be used for drinking, making ice, brushing teeth and food preparation until further notice,” the city said. “Boiling kills bacteria and other organisms in water.”

E. coli is found in water contaminated with human or animal waste. It causes diarrhea, cramps, nausea, headaches or other symptoms. The bacteria is especially dangerous for infants, young children, the elderly and people with compromised immune systems.

The city said it is working with the Minnesota Department of Health to determine the cause of the contamination, and has begun adding chlorine to the affected system. Residents are encouraged to stay tuned to the city’s website for updates.