Cal. Water Code § 1112

(a) Except as provided in subdivision (b), a hearing officer from the Administrative Hearings Office shall preside over a hearing in any of the following matters:
1. (1) A complaint issued under Section 1055.
2. (2) A notice of a proposed cease and desist order issued under Section 1834.
3. (3) A notice of a revocation of a permit issued under Section 1410 or revocation of a license issued under Section 1675.
(b) Subdivision (a) does not apply if the hearing notice includes, in addition to a proceeding under subdivision (a), consideration of a decision or order on a matter not subject to subdivision (a).
(c) In an adjudicative hearing presided over by the board or a board member, all of the following shall apply:
1. (1) Upon request by the board, a hearing officer from the Administrative Hearings Office shall assist the board or board member in conducting the hearing.
2. (2) The board may assign an adjudicative hearing, in whole or in part, to the Administrative Hearings Office.
(d) A hearing officer may perform additional work requested by the board, including, but not limited to, presiding over hearings on nonadjudicative matters, mediations, and overseeing investigations.
(e) A hearing officer may only perform the work specified in subdivisions (c) and (d) if the additional work does not conflict with the officer’s primary responsibility to serve as a hearing officer for matters listed in subdivision (a) and to resolve those matters in a timely manner.