Some residents of Sioux Lookout are being advised to boil their water before consuming.
The advisory is being issued after a contractor hit a watermain.
It impacts water systems on the north side of the CN rail line.
The Sioux Lookout Municipal Airport is also affected by the advisory.
A notice from the municipality says water from taps in the affected area should be boiled for at least one minute before being used for human consumption.
This includes brushing teeth, soaking false teeth, washing fruits and vegetables, adding to uncooked food or drinks, making ice cubes and water for pets.
The advisory will remain in effect until further notice.
