New clothes washer / sink connection

[danschy]

Greetings. I've done some looking around but can't find recommendations on my specific issue - what is the best way to connect a sink and clothes washer to an existing 3" drain. I've attached a quick drawing, which does not have accurate pipe sizes and fittings, but shows the general layout. I would like to tee off the existing 3" drain pipe with a 2" run, that will tee off to the sink, then to the clothes washer. I have three choices for the vent line - 1) between the the two p-traps as shown on the drawing, 2) between the 3" pipe and the sink connection, or 3) both places. Any suggestions?

 

[Cacher_Chick]

The fixture vent is always downstream of it's trap.

 

[Sponsor]

 

[danschy]

OK, but I don't think I can just move the vent connection to the left (my solution #2) because then the two tails are connected which I think is also a violation, so do I really need to go to two vent connections per attached file "washer-sink venting2", or is it preferable to go to two tees on the 3" drain (see attached file "washer-sink venting3"), which looks like more work , but I'll do it if that's really the right way.