Thick smoke was coming from the back of the one-story home in the 1000 block of Canterbury Lane when crews from multiple agencies arrived around 6:30 p.m., fire officials said.
The rear wall of the house was ablaze, and flames spread to the attic before the fire was controlled in about 10 minutes.
One firefighter suffered a minor hand injury from collapsing debris during overhaul operations, according to Contra Costa County Protection Fire District. No other injuries were reported.
Neighbors and Hercules police officers alerted the residents that their home was on fire and they escaped safely, fire officials said.
The three displaced residents, all adults, are receiving emergency housing assistance from the American Red Cross.
Fire officials estimate the damage to the house at about $8,000.
Crews from the Rodeo-Hercules Fire Protection District, Pinole Fire Department and the Crockett-Carquinez Fire Protection District also responded.