Zachary Droke was booked for possession of child pornography, oral copulation, lewd acts with a minor, and penetration by foreign object.
Droke had been renting a room at the house where the victim lived. During an interview Friday, he told investigators that he had sexually assaulted the 6-year-old on several occasions over the course of a year.
Investigators said they also found material related to the incidents on the suspect's computer.
Droke has no prior criminal history.
Anyone with information was asked to call Detective Ron Watson at (909) 395-2804. Information can also be left anonymously by calling We Tip at 1-800-78-CRIME.