Where would a vent stack be in this wall

[kwinch]

I'm remodeling our master bath. We have two 30 inch vanities with a 24 inch open space between them. Drain pipes go down into the basement of course but I'm wondering where a vent pipe would be. There is a bedroom above the plumbing wall and it's open right above this wall so it can't be going straight up. The floor joists run parallel with the wall so it probably goes between them over to the wall on the left which carries through to the attic.

The reason I want to know is, I want to put recessed medicine cabinets below the lights. If there is only one vent pipe in the center of the wall between the vanities I could make it work. I hate to cut out drywall just to see. I guess there is no way to determine before dong that?

 

[Gasmk1]

No way to tell as your vent won’t show with using a stud finder. Can you not trace from the attic space.

 

[kwinch]

I guess what I'm asking is with a typical installation like this would the two vanities' drains come together in a four way with the drain to the bottom and the vent to the top? Or would it be more likely there is a separate vent just off each vanity that ties together before going on up?

I'll get up in the attic but I don't think that will be very conclusive. I'll probably just cut out enough drywall to look in where the cabinets go but small enough that the cabinet will cover the hole if I still do a surface mount.

 

[kwinch]

Question answered. I opened the wall up enough to see there is no vent pipes. Only a 14/3 romex that I think I will be able to re-route without cutting even.

 

[oz-plumber]

You may not even have a vent in that wall.
Not all fixtures need vents.