A five-year-old boy in Quebec is being credited with saving his younger sister from drowning last week.

His three-year-old sister fell into a backyard pool on Tuesday in Granby, south of Montreal.

Her brother kept her head above water until the girl's mother came to the rescue.

Raynald Hawkins, of the province's Lifesaving Society, congratulated the boy for his quick thinking and warned parents that tragedies can happen suddenly when they aren't paying close attention to children.

"A few seconds can make all the difference," said Hawkins who advised parents to always stay within arm's reach of children near water.

"An infant begins to drown in 15 to 20 seconds. So the few seconds to answer a phone or question, 'Should I put on a life jacket?' can make all the difference."

Average of 10 deaths during Quebec holiday period

Hawkins said Quebec's annual construction holiday, when more people spend time near lakes, rivers and pools, is also a time when the society gets more reports of drowning deaths. He said there are usually about 10 drowning deaths each year during the two-week holiday period.

Hawkins added that young men 24 and under are at the highest risk of drowning because that age group is the most likely to engage in careless or risky behaviour.

"They are swimming in places where it's not appropriate, like rivers or lakes without a lifeguard on duty," said Hawkins.

Hawkins said young men often overestimate their swimming ability and sometimes don't wear lifejackets when they should.

"When you're on a boat, wear your lifejacket all the time. I think this is the basic rule," he said.

Dr. Louise Nolet, Quebec's chief coroner, said taking simple precautions could reduce the number of deaths this summer.

"I believe most drowning deaths could be avoided," she said.

Five drowning deaths have been reported in the province during the last week – including  two young brothers who died while swimming with their parents in a  river north of Lac Saint-Jean and a 58-year-old man who disappeared down a river in northern Quebec Saturday.