Cal. Bus. & Prof. Code § 25758
When a person attends as a witness in any criminal case in which a person is charged with a violation of any penal provisions of the law prohibiting or regulating the sale, exposing for sale, use, possession, giving away, adulteration, dilution, misbranding, or mislabeling of an alcoholic beverage or intoxicating liquor, and the court in the exercise of its discretion does not authorize the payment of the witness from county funds under Section 1329 of the Penal Code, the department may expend any money available to it to pay him witness fees at the rate of three dollars ($3) for each day's actual attendance and a reasonable sum for the necessary expenses of the witness, or, in the case of a witness attending from outside the State, to pay the witness the sum of ten cents ($0.10) for each mile and five dollars ($5) for each day that he is required to travel and attend as a witness.
Ca. Bus. and Prof'l. Code § 25758