(1) Plumbing must be installed and maintained in a manner which prevents cross-connections between the potable water supply and any non-potable or questionable water supply nor any source of pollution through which the potable water supply might become contaminated.

(2) A non-potable water system is permitted only for purposes such as air conditioning and fire protection and only if the system is installed according to law and the non-potable water does not contact, directly or indirectly, food, potable water, equipment that contacts food, or utensils. The piping of any non-potable water system must be durably identified so that it is readily distinguishable from piping that carries potable water.

(3) The potable water system must be installed to preclude the possibility of backflow. Devices must be installed to protect against backflow and back siphonage at all fixtures and equipment where an air gap at least twice the diameter of the water supply inlet is not provided between the water supply inlet and the fixture's flood level rim. A hose may not be attached to a faucet unless a backflow prevention device is installed.

(4) If used, grease traps must be located to be easily accessible for cleaning.

(5) If used, garbage disposals must be installed to preclude potential cross-connections between sewer and potable water systems. Garbage disposals must be maintained in a clean and sanitary manner at all times.

(6) There may not be a direct connection between the sewerage system and any drains originating from equipment in which food, portable equipment, or utensils are placed.