PVC drain pipe is connected between the kitchen sink drain baskets and the drain pipe that goes through the floor.

The starting point for this task is the sink basket. The smaller diameter threads are for the 1-1/2″ diameter drain pipe.

Kitchen sink drains normally use 1-1/2″ diameter drain plumbing. There is also 1-1/4″ diameter drain plumbing which is mostly used for bathroom sinks and other low-volume drains. Years ago all drain pipe were made from brass, which was usually chrome plated on the outside. Brass has a tendency to corrode and leak. PVC plastic, while seemingly cheap and weak is a much longer lasting material, truly corrosion-proof, for a lower price. Perhaps the only drawback of PVC is the possibility of over-tightening the threaded fittings and ruining the threads.

The sink drain kit includes fittings for two basins and a “T” junction.

The “S” trap fit includes the two-component trap and a piece of straight drain tube.

Note that there are some big differences between this PVC pipe and the PVC pipe that is glued together for building drain lines.

1. This pipe uses slip-joint connections, which allow the pipe to be adjusted in and out.
2. The outside diameter is the nominal size (the stated or the the named size), where the glued-together PVC pipe the nominal size indicates the inside diameter. This means that the slip-joint drain fittings will slide inside the glued-up drain pipe, and there are threaded-to-glued adapters where this happens.

This metal nut connects the drain tail-piece to the sink basket. This short tail-piece came with the kit, but I also bought longer tail-pieces because I prefer them.

The longer tail-piece actually came as one part that is sawed in half to make two tail-pieces.

I assembled the drain parts that I figured I would need. This layout shows the form that the pipes would follow… if the sink drain line goes downwards through the floor.

Most newer houses use a horizontal drain line that runs into the wall (and then turns downward, eventually). Horizontal drains are easier because there is no need to drill holes in the bottom of the sink base cabinet.

When a horizontal drain pipe is present (which is more common than vertical) then a P-trap would be used instead of an S-trap.

The metal nut (which came with the sink basket) was installed over the tail-piece, and the plastic washer was inserted. I’m not sure if the plastic washer is needed with PVC pipe, but it certainly is needed with metal pipe.

This assembly was attached to the sink basket. I used pipe thread compound to help

seal the joint and allow for easy removal later

Below the tail-piece is an elbow which leads to the other basin

Completion:

At the other basin there is a “T” junction fitting, which leads into the “S” trap, which leads into the building drain. All of these pipe are connected with slip-joint fittings, which can be removed easily for repairs or cleaning.