There shall be an efficient drainage and plumbing system for the plant and premises.

(a) Drains and gutters. All drains and gutters shall be properly installed with approved traps and vents. The drainage and plumbing system must permit the quick runoff of all water from plant buildings, and surface water around the plant and on the premises, and all such water shall be disposed of in such a manner as to prevent a nuisance or health hazard.

(b) Sewage and plant wastes.

(1) The sewerage system shall have adequate slope and capacity to remove readily all waste from the various processing operations and to minimize, and if possible to prevent, stoppage and surcharging of the system.

(2) Grease traps which are connected with the sewerage system shall be suitably located but not near any edible products department or in any area where products are unloaded from or loaded into vehicles. To facilitate cleaning, such traps shall have inclined bottoms and be provided with suitable covers.

(3) Toilet soil lines shall be separate from house drainage lines to a point outside the buildings unless they are positively trapped to prevent backing up. Drainage from toilet bowls and urinals shall not be discharged into a grease catch basin.

(4) All floor drains shall be equipped with traps, constructed so as to minimize clogging, and the plumbing shall be so installed as to prevent sewerage from backing up and from flooding the floor.

(5) Floor drainage lines should be of metal and at least 4 inches in diameter and open into main drains of at least 6 inches in diameter and shall be properly vented to outside air.

(6) Where refrigerators are equipped with drains, such drains should be properly trapped and should discharge through an air gap into the sewer system. All new installations, and all replacements, or refrigerators equipped with drains shall meet these requirements.