I am looking at some bath vanities from IKEA.

Most bath vanities with drawers will have a notch in the middle due to the drain tailpiece and P-trap interference so you end up with a U shaped drawer.

IKEA vanities with drawers do not have this U shaped configuration because of a "unique design".



So basically the drain has a sharp and abrupt 90 to run the pipe very close to the back wall, in essence offseting the tailpiece.

Is this design a good design or bad design?

It seems to me this design will clog more often with the sharp 90 turn?

In addition, the piping being offset much closer to the back wall, the rough in piping and trap adapter needs to be not "in the middle" right? Say you have a 36" vanity normally you would rough in the drain at 18" over. With this IKEA design, the pipe goes to the back wall, your P-trap will need to be turned 90 degrees flat against the wall, since your sink drain hole is 18" over, the drain rough in on the wall needs to be offset the lateral distance of the P-trap over so you can swing the P-trap against the wall? Am I thinking right?

The 90 offsets are basic ADA designs and may clog easier than normal but at the same time gives you a functioning full drawer the drain location can vary within the parameters of the shelves/drawers

Most designers give little thought to how the sink will actually drain and be serviced

i can't tell how tight that is but it's not much different from a bathtub shoe.

Without a straight tailpiece I guess a pop up drain is not possible, so need to use those push down stopper?

affectionately known as an "umbrella drain"..

I would agree on the rough in having to be over to one side so that the trap can fit flat against the back wall. In addition to the drawers not needing to be notched, that trap configuration gives you a lot more usable space under the sink for storage. I agree with Packy about the design looking like a bathtub shoe...in my limited experience, most bathroom sink clogs result from hair forming a blob around the pop-up assembly, having a push drain should eliminate most clog issues.