California Code, Business and Professions Code - BPC § 108.5

In any investigation, proceeding, or hearing that any board, commission, or officer in the department is empowered to institute, conduct, or hold, any witness appearing at the investigation, proceeding, or hearing whether upon a subpoena or voluntarily, may be paid the sum of twelve dollars ($12) per day for every day in actual attendance at the investigation, proceeding, or hearing and for the witness's actual, necessary, and reasonable expenses and those sums shall be a legal charge against the funds of the respective board, commission, or officer; provided further, that no witness appearing other than at the instance of the board, commission, or officer may be compensated out of the fund.

The board, commission, or officer shall determine the sums due to any witness and enter the amount on its minutes.