Toronto police say the alleged incident occurred at an apartment in the St. Clair Avenue East and O'Connor Drive area.
Det.-Sgt. Jim Gotell told CBC News that the 23-year-old woman was having a repair done, which is why the superintendent was invited in to her apartment.
Gotell said it is alleged that after the repair was complete, the superintendent left the apartment and returned with a work order for the victim to sign, which is when the alleged assault took place.
Trevor Wilks, 54, is charged with sexual assault. He was due to appear in court on Wednesday morning.
The allegations against him have not been proven in court.
Police say there may be additional alleged victims. Investigators have released a photo of the accused.
Gotell said the accused is a superintendent at several different buildings.
Anyone with information is asked to contact investigators at 416-808-5400. Information can also be passed on through Crime Stoppers at 416-222-8477.