Most of Gatineau's Hull sector will soon be under a boil-water advisory while a nearby water treatment plant undergoes major work.

The advisory covers the entire district except for the Plateau neighbourhood, which will temporarily get its water from the Aylmer plant.

The advisory begins at 7 a.m. on Saturday, Oct. 20, and is expected to last at least five days.

Coun. Maude Marquis-Bissonnette likened the work required at the plant to "open-heart surgery."

The work is part what the city describes as a major expansion and modernization of the Hull treatment plant, which processes water for more than 86,000 residents.

The area outlined in red will be under a boil-water advisory starting Saturday, Oct. 20, at 7 a.m. (City of Gatineau)

Residents affected by the advisory are asked to cut back their water usage and boil their water for at least a minute before drinking it or using it to brush their teeth.

Tap water may be slightly discoloured and water pressure may decrease while the work is being done.

The city said it will let residents know when the advisory ends.