All fixtures located in the kitchen, including the dishwasher, shall be installed so as to empty into a drain which is not directly connected to the sanitary house drain. Kitchen drain may empty into a manhole or catch basin having a perforated cover with an elevation of at least 24" below the kitchen floor evaluation, and hence to the sewer. Exceptions: existing licensed institutions which have no plumbing fixtures installed on floors which are above the floor on which the kitchen is located.
15 Miss. Code. R. 16-1-41.12.2