A residential kitchen is a kitchen in a private home where foods are generally made for family or charitable purposes such as a bake sale. This does NOT require a permit.
However, certain food-based activities in a residential kitchen DOES require a permit. If residential kitchen is in a bed-and-breakfast operation or a part of a cottage food operation then it DOES require a permit. Any preparations or events that would provide food “direct to the consumer” such as a farmer’s market or sales by mail/internet DOES require a permit.