California Code, Government Code - GOV § 11430.10

(a) While the proceeding is pending there shall be no communication, direct or indirect, regarding any issue in the proceeding, to the presiding officer from an employee or representative of an agency that is a party or from an interested person outside the agency, without notice and opportunity for all parties to participate in the communication.

(b) Nothing in this section precludes a communication, including a communication from an employee or representative of an agency that is a party, made on the record at the hearing.

(c) For the purpose of this section, a proceeding is pending from the issuance of the agency's pleading, or from an application for an agency decision, whichever is earlier.