Some Michigan residents are under a boil water advisory after a leak was discovered in a major water main that serves the Detroit area.
The Great Lakes Water Authority said it discovered a break early Saturday on a 10-foot water transmission main that distributes drinking water from its Lake Huron Water Treatment Facility.
Out of an "abundance of caution," the water authority issued a precautionary boil water advisory that initially covered 23 communities serviced by the water main, representing an estimated 935,000 people, it said in a statement.
After reviewing water pressure data, the water authority later lifted the advisory for 11 of the communities and added one, with 13 communities now covered as of Saturday afternoon. The affected area impacts approximately 288,000 people.
Businesses in Greenwood and Imlay Township also are potentially impacted, the water authority said.
The water authority listed the city of Flint among the initial 23 affected communities. But city officials in Flint said they switched to a secondary water supply line following the emergency alert from the Great Lakes Water Authority, which is its primary water source. The city's water quality therefore is unaffected and residents do not need to boil water, the officials said.
Great Lakes Water Authority crews were working to isolate the leak -- which was identified in Port Huron, approximately one mile west of the Lake Huron Water Treatment Facility -- to begin repair work.
"Once the leak is isolated, crews will begin to open emergency connections to other mains in the system to restore some flow to the impacted communities," the authority said.
The water authority is also investigating the cause of the leak.
A loss of water pressure in a water system could lead to bacterial contamination, officials warned. As a precaution, impacted residents are urged to boil water for at least one minute before drinking it, or use bottled or disinfected water, until further notice.
The boil water advisory will be lifted once sampling shows the water is safe to drink, the water authority said.
It is unclear how long it will take to repair the water main break.