Residents of Haida Gwaii are being asked to cut their water consumption by a full third.
The province has upgraded the islands to drought level 3, thanks to low stream and groundwater levels.
Staff with the Ministry of Forest Lands and Natural Resources say they may need to raise the drought level again, if dry weather continues.
The ministry is also warning of the impact on fish, which could be pulled into water systems as stream levels drop.
Salmon could also be blocked from reaching their spawning grounds if water levels are too low.
Haida Gwaii is not alone in facing water shortages.
The West Coast of Vancouver Island has also hit drought level 3, while the east coast of the island has been upgraded to level 4.