The Saskatoon Health Region says a pipe burst around midnight and the rupture caused flooding in several areas, including the pediatric outpatient area and the coronary care unit.
Some patients in coronary care have also been moved to other areas of the hospital.
The region says most procedures will still go ahead, so people should go to their appointments unless they've been contacted by the hospital or their surgeon.
It is not yet known how long the clean up might take.
The region also says staff are assessing any potential risks for the spread of infection.
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