The complaint against District Judge Pat Murdoch says a detective heard about the tape from an informant and bought it for $400.
Police then questioned the woman, who says Murdoch solicited her on a prostitution website.
The woman says she met with the judge about eight times and he paid her $200 each time. She says he forced himself on her during one visit, but she returned and secretly recorded a second forced encounter.
Murdoch is out on bond. His first court appearance is Thursday.
He does not have a listed phone number and his office did not know who will represent him.