And yet another "add sink in the laundry room" post!

[Mark Krajewski]

Our laundry room doesn't have a sink (go figure). I intend to remedy this soon. I opened the walls and there is a 2" standpipe for the washer drain connected to a 2" vent. I want to add:

• A utility sink in a vanity in the laundry room
• A wall mount utility sink in the garage (on a common wall shared between the laundry room and garage)

A picture may speak a thousand words. The blue lines represent existing plumping lines. The orange-ish ones are the new lines.

Questions:

• Can one drain line shared by two sinks? I'm guessing that line has to be 2" diameter.
• What needs to be done for venting (assume that the new line installs just above the existing laundry line tee)?
• Would an Air Admittance Valve on the utility sink in the garage suffice? I'm trying to stay away for running another vent through the roof.
• Any other thoughts on how to do this well (besides maintaining a good pitch on the new run)?

Why two sinks so close? Well, one for my wife to use as she sees fit, and one for me in the garage where I clean out paint brushes, clean sprinkler parts, etc. without messing up "her" sink.

Appreciate any help in advance. Other suggestions or concerns are welcome!

 

[Jadnashua]

The laundry sinks still need their own p-trap(s). You can combine them, and use one p-trap, or use one for each sink. You don't need a complete, separate vent for the sinks, but what you have won't cut it if I understand things. You'd want to probably replace the WM connection into the stack with a double-wye, and on the trap arm of the sink(s), run a vent line vertical up to at least 42" above the floor, then, you can connect into the existing vent.

I'm not positive on this, but think I'm correct.