Emergency responders arrived at the home in Montreal's suburbs around 2:45 p.m. ET and attempted to resuscitate the toddler before she was taken to Cité de la Santé Hospital.
Efforts to revive her at the hospital failed.
It was not immediately known what led to the drowning.
The girl's death is the 41st drowning this year in Quebec — 12 more than at the same time last year.
That rise could be explained by warm weather, which "increases the probability of incidents and accidents," Quebec Lifesaving Society director Raynald Hawkins said earlier this week. Hawkins urged people to heed security precautions.
The previous tragedy occurred Wednesday, when a 16-month-old girl died in the Montreal suburb of Kirkland.
Following that incident, Quebec Health Minister Yves Bolduc encouraged people to be careful when going in the water.
"It's true we have more drownings this summer," he said. "It's worrying when you look at it." Bolduc is in favour of children being taught water safety as soon as possible — but he said adults also have to take responsibility.