California Code, Health and Safety Code - HSC § 113969

(a) Except as specified in subdivision (b), all food employees preparing, serving, or handling food or utensils shall wear hair restraints, such as hats, hair coverings, or nets, which are designed and worn to effectively keep their hair from contacting nonprepackaged food, clean equipment, utensils, linens, and unwrapped single-use articles.

(b) This section does not apply to food employees, such as counter staff who only serve beverages and wrapped or prepackaged foods, hostesses, and wait staff, if they present a minimal risk of contaminating nonprepackaged food, clean equipment, utensils, linens, and unwrapped single-use articles.