How to Install Plumbing Drains for a Bar Sink

Remove the strainer nut and accompanying washer from the underside of the bar sink's strainer. Slide the nut, threads facing up, over the smooth end of the sink basin tailpiece. Place the washer inside the flange-end of the tailpiece. Press the flange-end of the tailpiece into the strainer's bottom opening. Press the nut's threads against the strainer's threads and turn the nut clockwise to tighten. Tighten the nut until hand-tight to secure the tailpiece to the strainer.

Align the P trap's lower opening with the wall-drain inlet, usually located at the rear of the under-sink cabinet. Place the trap's upper opening against the side of the installed tailpiece. Use a marker to mark the location of the rim of the trap's upper opening on the side of the tailpiece.

Draw a second mark 1 to 2 inches below the first mark; the second mark indicates where you must cut the tailpiece to align the trap's lower opening with the wall-drain. The mark has to be 1 to 2 inches below the rim mark to allow for the length of tailpiece pipe that must protrude into the trap's upper opening. Lengths might differ according to tailpiece and P trap models; adjust the length to suit your components, if necessary.

Remove the tailpiece from the strainer. Cut the tailpiece to size at the lower mark, using a hacksaw. Reattach the tailpiece to the strainer. Remove the nut and washer from the trap's upper opening. Slide the nut, threads facing down, and then the washer over the open end of the tailpiece.

Slip the trap's upper opening over the tailpiece, slide the nut against the trap's rim and snug the nut against the trap's threads. Twist the nut clockwise to engage its threads with the trap's threads and join the tailpiece to the trap. Rotate the trap to align its lower opening with the wall-drain inlet. Use a tape measure to gauge the distance between the trap and inlet.

Mark the distance on the trap extension pipe with a marker, adding 1 to 2 inches to accommodate the portion of the pipe that must extend into the inlet's opening. Cut the pipe to size with a hacksaw. Remove the nut and washer from the trap's lower opening.

Slide the washer and then the nut over the smooth end of the extension; position the nut's threads facing the curved end of the pipe. Insert the curved end of the pipe into the trap's opening, press the nut's threads against the trap's threads and twist the nut clockwise to join the separate components.

Remove the nut and washer from the wall-drain inlet fitting. Slide the nut and then the washer over the pipe's open end. Position the nut's threads facing the pipe's open end. Twist and gently bend the trap to slip the pipe's open end into the drain inlet's opening. Slide the washer and nut against the inlet's threads.

Twist the nut clockwise to tighten and join the components. Tighten all of the drain assembly's nuts approximately one-quarter rotation past hand-tight. Run water through the bar sink's drain to check the joints for leaks.