California Code, Health and Safety Code - HSC § 114217

(a) A potable water tank of sufficient capacity to furnish an adequate quantity of potable water for food preparation, warewashing, and handwashing purposes shall be provided for nonpermanent food facilities.

(b) At least five gallons of water shall be provided exclusively for handwashing for each nonpermanent food facility. Any water need for other purposes shall be in addition to the five gallons for handwashing.

(c) Except as specified in subdivision (d), at least 25 gallons of water shall be provided for food preparation and warewashing.

(d) At least 15 gallons of water shall be provided for nonpermanent food facilities that conduct limited food preparation.

(e) The water delivery system shall deliver at least one gallon per minute to each sink basin.