A water main break has prompted the Great Lakes Water Authority to issue a mandatory boil water alert for 11 Oakland County communities.
The alert has prompted dozens of school closings Tuesday.
The Great Lakes Water Authority said Tuesday morning water was shut off in Novi because of the water main break.
Repairs could take up to five days.
The transmission main break on 14 Mile Road between Farmington and Drake sparked a drop in water pressure, authority officials said.
Residents must bring all water to a boil for at least one minute before using.
Boiled, bottled or disinfected water should be used for drinking, making ice, washing dishes, brushing teeth and preparing food until further notice.
Boiling water before using will kill bacteria and other organisms that may be in the water.
The GLWA will alert affected communities when the boil water advisory has been lifted.
Guidelines on reducing the risk of infection by microbes are available from the EPA Safe Drinking Water Hotline at 1-800-426-4791.