Ottawa's fire chief says two fires this week in or near evacuation zones underscore the need for people to leave their homes if they're asked.

Kim Ayotte says he understands people's desire to protect their homes, but it's not worth the risk.

A family of three escaped a fire at their Constance Bay home Wednesday morning, the second time in a span of 30 hours flames have damaged flood-threatened homes in Ottawa's west end.

Firefighters received a 911 call at 5:24 a.m. reporting flames and smoke coming from the small grey bungalow at 106 Allbirch Rd., on the shore of the Ottawa River.

"Today's fire is a prime example of why we need to limit access," Ayotte said at a city news conference Wednesday.

"A home can be replaced. A human life can never be replaced."

A man, woman and child were able to escape the home uninjured. (Giacomo Panico/CBC)

Tyler Murphy was helping next door to repair a sandbag wall protecting both properties when he noticed the fire.

"When I went to get more sandbags I smelt smoke, so I looked into the windows on the house and I just saw flames coming up. I just started yelling, 'Fire, fire!' and alerted the people in the house," Murphy said.

Firefighters said a man, woman and a child were able to exit the home without assistance.

Deputy fire chief Paul Hutt says residents in flood zones should evacuate their homes if asked to do so because emergency crews may not be able to reach them. 0:38

'Situation is very serious'

At the time of the fire, water covering the stretch of Allbirch Road in front of the homes had reached a depth of approximately 50 centimetres.

The street is not part of the current evacuation zone, but is nearby. The Ottawa River continues rising toward its peak, now expected Thursday.

That complicated things for firefighters.

"The situation is very serious. You can't walk into water with regular firefighting equipment," said Paul Hutt, deputy fire chief for the area.

Tyler Murphy was helping friends repair a break in a sandbag wall when he smelled smoke and alerted the residents next door. (Giacomo Panico/CBC Ottawa)

A water rescue unit from nearby Fitzroy Harbour was deployed to assist in battling the fire and check for injured occupants.

"We can't go inside the house because we're not protected with proper protective clothing," Hutt said.

Residents advised to leave

Late Monday night, a separate fire destroyed a house on nearby Bayview Drive.

No one was injured in that fire, either.

Flooded roads in the region and concerns over fires from overworked water pumps and wet hydro connections have led emergency officials to call for voluntary evacuations.

In Constance Bay alone, residents of 300 homes have been told to leave, though many have vowed to continue operating pumps and sandbagging their homes.

Fire officials have yet to reveal the causes of the two fires.