I think that could be done, but you may not even need that.

Where and how is this washing machine connected to what drain ? ( an existing drain pipe ? )

i do not have a washing machine or hookups currently but want to soon.

just wanted to know if its legal to tie in a washer drain vent to one of the bathroom or kitchen drain vents.

Down here in GA my plumber used a "Studoor" (sp) vent and my remodel. It sits off next to the drain line and acts as a vent but automatically closes to keep sewer gas and water out of house.

post this over inteh plumbing forum. lazy pup can tell you the exact legal requirements if you tell him which code you are under.

being an apartment, i think building management will have their own rules as well.

i have a studor vent on my washing machine drain line as well. seems to work well

studor vent(AAV) are not allowed in many areas. it all depends on your local codes. the easiest way to find out is to call teh local permit office and speak to the inspector. then GET IT IN WRITING when you pick up the permit that the AAV is allowed. you would be surprised how many folks are told by "someone" at the permit office that soemthing is ok, then when the inspector comes it is not allowed. the best bet is to take a set of drawings along when you go to get the permit and have them stamp it approved, then you have a leg to stand on if the inspector does not like it.