Darrel Keith Pitchford, 49, was arrested Saturday morning at his home in the 100 block of Village Circle, Novato police Sgt. Keith Heiden said.
The 25-year-old woman's mother informed police about the rape on Wednesday, Heiden said. Pitchford and the alleged victim are acquaintances who worked together, Heiden said.
Pitchford is a grocery clerk, according to the Marin County jail booking log. He is being held under $100,000 bail.
The woman's mother said her daughter has the mental capacity of a young child. The alleged rape happened Wednesday at Pitchford's home, Heiden said.