California Code, Code of Civil Procedure - CCP § 1775.6

In actions submitted to mediation pursuant to Section 1775.3, a mediator shall be selected for the action within 30 days of its submission to mediation. The method of selection and qualification of the mediator shall be as the parties determine. If the parties are unable to agree on a mediator within 15 days of the date of submission of the action to mediation, the court may select a mediator pursuant to standards adopted by the Judicial Council.