The fire was reported at about 1:10 p.m. at a house at 42940 Parkwood St., according to the fire department.
A 78-year-old woman, the mother of the homeowner, was found sitting on the sidewalk outside the home in distress. She was transported to Washington Hospital for evaluation, according to the fire department.
A firefighter suffered minor burns to his hands and shoulder.
The house and its contents appear to be a complete loss, according to the fire department. The cause of the blaze is under investigation.
