California Code, Health and Safety Code - HSC § 114099

(a) Manual warewashing sinks, except as specified in subdivision (c), shall have at least three compartments with two integral metal drainboards for manually washing, rinsing, and sanitizing equipment and utensils.

(b) Sink compartments shall be large enough to accommodate immersion of the largest equipment and utensils. If equipment or utensils are not designed to be washed in a warewashing sink, alternate approved methods as specified in Section 114099.3 shall be followed.

(c) A two compartment sink that is in use on January 1, 1996, need not be replaced when used as specified in Section 114099.3. The enforcement officer shall approve the continued use of a two-compartment sink even upon replacement if the installation of a three-compartment sink would not be readily achievable and where other approved sanitation methods are used.