How to Install Double Vanity Plumbing

Insert the slip nuts and washers over the ends of the sink drains’ tailpieces. Thread 90-degree pipe elbows onto the slip nuts on the tailpieces using your hands, if the stubout in the wall sits between the two sink drains.

Thread a sanitary tee onto the tailpiece for the drain that sits closest to the stubout, if the stubout is not centered between the drains. Thread a 90-degree arm on the other drain’s tailpiece.

Attach another 90-degree pipe elbow to the stubout in the wall, pointing the open end of the elbow down. Thread a p-trap onto the other end of the pipe elbow and a riser to the open end of the p-trap. Thread the end of the riser to the sanitary tee attached to the one tailpiece, or thread a double 90 degree tee onto the end of the riser if the stubout sits between the drains.

Measure and cut with a hacksaw straight lengths of pipe to attach the pipe elbows that sit on the tailpieces to the double 90-degree tee or the sanitary tee, depending on the location of the stubout.

Turn on both sinks’ faucets and allow the water to flow down the drains unobstructed. Watch the drainpipes under the sink for 5 minutes, looking for any leaks to appear. Tighten the nuts at any leaking pipe joints, turning them an eighth of a revolution with a pipe wrench.