Add 2nd basin drain to exisiting single drain configuration

[doinitright]

This drain and vent stack are to the left side of 73" wide space for vanity. I'd like to rough in for 2nd basin to the right, before reconstruction of bathroom. 1970's build date. See pictures of existing status. Not sure how and what fittings to use here. I understand need to extend hot and cold supply lines to the right after drainage piping for right side basin completed. My understanding in Santa Clara, CA is that no plastic through walls on this 3 story condo building where this is ground floor unit on slab. Want to minimize intrusion into rear of custom vanity to be installed later, yet I recongnize that with only 2x4 wall thickness, some wrap around necessary to get around right drain line. Code approved suggestions much appreciated.

 

[MicEd69]

It looks like this is a major renovation. I would sure replace all that galvanized piping if I was spending as much money as you seem to be spending.

Is that area behind the wall a closet of just a pipe chase? In any case, I would use that area to run the drain piping for your double vanity.

 

[doinitright]

It looks like this is a major renovation. I would sure replace all that galvanized piping if I was spending as much money as you seem to be spending.

Is that area behind the wall a closet of just a pipe chase? In any case, I would use that area to run the drain piping for your double vanity.

Yes, its a closet that is not deep and don't wish to loose that limited space. Looking to do what's needed in front or on this side of wall. Can easily replace the vent line. Don't want to mess with the drain line on right. Any suggestions for a fitting to replace the upper fitting that will serve as two 1.5" inlets for each of two basins?

 

[doinitright]

Yes, its a closet that is not deep and don't wish to loose that limited space. Looking to do what's needed in front or on this side of wall. Can easily replace the vent line. Don't want to mess with the drain line on right. Any suggestions for a fitting to replace the upper fitting that will serve as two 1.5" inlets for each of two basins?

Also, I'd think whatever fitting may work behind the wall would likely be relevant and apply to doing same type modification in front of wall, to a certain extent.