Fire broke out at their apartment complex near Fresno Street and E Street at about 10:30 Thursday morning.
Investigators say the small fire started in a heating unit and triggered the building's sprinklers.
Residents spent some of the day mopping up.
"Upon investigation we found a small fire that had been extinguished by a sprinkler head in a heating unit, so the fire was contained to that unit. Now we are just dealing with water issues," Capt. Christian Palmer of the Fresno Fire Department said.
Firefighters say the flooding was limited to the building's hallway.
The good news is that no one was hurt.