California Code, Government Code - GOV § 11445.40

(a) Except as provided in this article, the hearing procedures otherwise required by statute for an adjudicative proceeding apply to an informal hearing.

(b) In an informal hearing the presiding officer shall regulate the course of the proceeding.  The presiding officer shall permit the parties and may permit others to offer written or oral comments on the issues.  The presiding officer may limit the use of witnesses, testimony, evidence, and argument, and may limit or eliminate the use of pleadings, intervention, discovery, prehearing conferences, and rebuttal.