CAL. HSC. CODE § 114311 : California Code - Section 114311

Mobile food facilities not under a valid permit as of January 1, 1997, from which nonprepackaged food is sold shall provide handwashing facilities. The handwashing facilities shall be separate from the warewashing sink.

(a) The handwashing sink shall have a minimum dimension of nine inches by nine inches in length and width and five inches in depth and be easily accessible by food employees.

(b) The handwashing facility shall be separated from the warewashing sink by a metal splashguard with a height of at least six inches that extends from the back edge of the drainboard to the front edge of the drainboard, the corners of the barrier to be rounded. No splashguard is required if the distance between the handwashing sink and the warewashing sink drainboards is 24 inches or more.

(c) This section shall not apply to mobile food facilities handling only whole produce or the bulk dispensing of nonpotentially hazardous beverages.