The one-alarm blaze was reported at about 7:15 a.m. at a single-family home on Serrano Avenue, in an unincorporated area off of East Hills Drive, fire Capt. Mary Gutierrez said.
Gutierrez said responding firefighters saw smoke as they approached the house, and then saw that about half of the 1,400-square-foot home was on fire.
Eight people, including 2-year-old twins, were inside the house at the time of the fire, but all were evacuated safely.
One person was evaluated at the scene for smoke inhalation, but no other injuries were reported.
The family was sleeping when the fire started, and were alerted by one of the family members who woke up and felt the heat, Gutierrez said.
She said some of the occupants had to escape through a back door because the fire was so intense in the front of the house.
As of 9:30 a.m., firefighters were still at the scene.
The Red Cross responded to provide assistance to the displaced family.
The cause of the fire is under investigation. A damage estimate was not immediately available.