Food Service Codes in California are State Codes enforced by County Public Health Depts and questions asked in different counties get different answers----depending on that county's enforcement. It is hard to suggest anything to anyone unless they live in the same county--------but here are things that I have found here:
Health Dept wants to know exactly where the water in the potable water tank came from, and it must come from a kitchen or building that has been inspected---seems stupid when the whole city has the same water supply--but it is enforced here.
Waste water tank must have 1 1/2 times the volume of the potable water tank----seems stupid to me----the water does not multiply as it goes through the sink.
Most inspectors also require a "hand Washing" sink----separate from the dish washing sink
Some inspectors say that a three tub sink is not needed if disposable chafing trays and throw away utensils are used
Some inspectors say that the 3 tub sink only needs to be big enough to wash the biggest item that you are washing----so if using disposable items----just big enough to wash knives
best thing to do is talk to a local inspector