Christopher Colin Ward, 44, of Indian Corn Drive is charged with third degree criminal sexual conduct, Charleston Police said.
He is being held in the Berkeley County Detention Center, where he is scheduled to have a bond hearing at 7 p.m.
The incident that led to the charge against Ward is alleged to have occurred on Dec. 3 in Ward's residence, police said.
Ward was a reserve officer for five years with the Charleston Police Department.
The investigation is ongoing.