Treatment plant problems caused 1.4 million Phoenix residents to boil their drinking water or use bottled water, the Associated Press reported.
Due to recent storms, muddy water was flowing into one of the city's two operating water treatment plants, reducing the output of that plant, officials said.
Two other treatment plants were shut down for maintenance, and a third because of damage, leaving only one of the city's five water treatment plants producing water at full capacity.
In addition to boiling water for drinking, residents were told to take short showers and shut off landscape watering.
Ken Kroski, a spokesman for the Phoenix Water Services Department, said there were no health effects from "turbidity," or cloudiness in the water because of the muddy water in the intakes. However, it could interfere with water disinfection, provide a medium for bacterial growth, and indicate a presence of disease-causing organisms, Kroski told the Associated Press.