The Watertown Fire Department got the call for the fire at 119 Boyd St. around 12:30 a.m. Saturday, said Watertown Deputy Fire Chief Robert Iannetta.
"It started on porches in the back of the house - we are almost positive from smoking materials," Iannetta said. "One of the occupants smelled smoke, opened a door on the second floor and it came in. The fire knocked him down and he couldn’t close the door."
The fire was blazing when firefighters from Watertown and Newton arrived at the scene on the area south of the Charles River. The home is the last one in Watertown before the Newton line. It is also tucked behind two homes.
"The house is set back 75 feet form the road," Iannetta said. "It made access difficult. We couldn't get any trucks near it."
The fire was three alarms - one each for Watertown and Newton, and a second added by Watertown - Iannetta said.
Residents of the home were not injured, but they were burned out of their homes.
"It might be a total loss," Iannetta said. "There was fire and smoke damage on the second and third floor, and water damage in basement and first floor."
One cat was saved and and a second was missing, but the owner told firefighters that she thinks it ran away during the fire. No firefighters were injured.The American Red Cross responded to the scene and gave sweatpants and a sweatshirt to one resident, as well as providing food and drink to firefighters and other first responders.