Laundry sink addition to existing adjacent bathroom plumbing

[Lisa Burris]

I am redoing my laundry room, and hoping to install a laundry sink. The wall the sink will go on has a half bath on the other side (leading me to originally think it would be easy to hook into). Upon opening everything up I’m not quite sure about the vent situation. I’ve attached a picture - the new sink will sit between the existing sink and toilet plumbing, I was thinking I could insert a wye to tie the new sink into the drain line, but how to tie into the vent stack?

Also wondering if this is even allowable by code, I know a second sink is allowed when on the same side of the wall, but feeling unsure since this will be the same wall but other side. Hoping I won’t need a full new vent - that is definitely beyond my skill set.

Also just wanted to say thanks to everyone - this is my first post but I used other topics extensively during the guest bath gut we completed earlier this summer. This site and its members are really invaluably helpful, just wanted to say how much I appreciate everyone.

 

[Terry]

One way to add a second sink.
For code purposes, the laundry sink has 2" up to the santee and then can use a 1.5" vent and trap arm.
The ones above are bathroom lavs.

 

[Sponsor]

 

[Lisa Burris]

Ah, that makes a lot of sense, thank you. And, with that approach, am I right to interpret that as that I will I need to redo the original sink drain to sit above the original drain line and have its own vent as well as for the new sink? I tried to mock up my interpretation of your advice in the attached picture.