Z: are you sure that the drawer goes all the way to the back of the vanity? I would think the Mfr. left room for the plumbing.
I was considering that but there are a couple of issues.I would do all new piping with pex.
Oh, I wish I could just easily get a different plumber out here. My problem is there are only 2 licensed residential plumbers in my area and I don't know if either one of them knows about PEX. The one I use works on DWV systems but I've been told that he doesn't sweat pipes. He's the son of my late plumber. The other guy charges $20 more per hour than my current guy. I've been told he sweats pipes and will do water supply stuff but that he won't touch DWV stuff. My friend hired him for some work and the guy basically came out and told him what parts to buy and how to hook everything up, charged a high fee, and left. The DWV guy shops at the less expensive local hardware store with the nicer employees. The other guy shops at the more expensive place with the rude employees (with the owner who gave me stinkeye for pointing out that its a code violation to use a sanitary tee in a horizontal position). I'm in sort of a No Man's Land for services and people have to be sent from other states to do things sometimes.i used copper in my walls, and plastic under the house
when i plumbed it, I sweated an adapter on the pipe before i shoved it thru the floor
then hooked up all from under neith. 3/4 copper to all fixtures, stubbed out with 1/2
1" from the meter to the heater
if your plumber is not familar with pex. find another plumber