Water is essential to the kitchen: It's an ingredient in cooking, a tool for food preparation and a requirement for post-meal cleanup. With all that action going on at the sink, why do most kitchens have only one? Adding a second sink in your kitchen design can double its functionality without adding square footage. A prep sink also allows multiple cooks to work in comfort simultaneously and prevents dirty dishes from getting in the cook’s way. But to get the most out of a prep sink, you have to put it in the right place.