Dr. Catherine Whiting, the city's medical officer of health, has issued a drinking water advisory for all residents and properties of CFB North Bay and the Jack Garland Airport.
It's the second drinking water advisory for the area in the last month.
The advisory only affects people using the municipal water system, and was triggered by a loss of pressure.
Blew a piston
City administrator David Linkie said the advisory stems from Monday night's thunder storms and a resulting power outage in the city.
Linkie said when the power cut a diesel-power back-up pump atop Airport Road kicked-in but soon blew a piston. That caused the loss of pressure.
Until further notice tap water shouldn't be used for drinking, brushing teeth or washing dishes.
Residents in the rest of the city may use tap water as usual.
Water from the fire department
Pressure is being restored and the system will be flushed over the next 24 hours, during which time some discolouration may be noticed, the North Bay and District Health Unit said.
Normal use of water from taps should resume within 72 hours based on lab testing.
Those affected by the drinking water advisory may get water from the fire department at the Princess Street or McKeown Street sites. People should bring their own clean containers.
The health unit will continue monitoring the situation and Whiting will notify the public when the drinking water advisory has been lifted.