Due to some issues in the upstairs bathroom I am finally gutting both of them and starting over. This includes redoing the DWV system because currently there is only the roof vent for every fixture and some of the lines are galvanized.

I sketched it up (See here: [i.imgur.com]) and have some questions about venting the upstairs bathroom. The only fixture above the toilet/tub is the lavatory. Do they require their own vent or is this a satisfactory wet vent? Anything else look wrong here?



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drain the upstairs toilet into a sanitary tee with a side inlet.
drain the downstairs lav into the toilet vent.
you need to rework the laundry and laundy sink connection as they are not vented.

I originally did want to drain the sink into that vent, but with the bottom fitting being a 3" elbow with a 2" side-inlet for the vent/drain I didn't think it could be used to change flow from Vertical to Horizontal.

Would a single vent situated between the traps of the standpipe and laundry sink be permissible or do I need a vent per trap?

I'll redo that drawing the revamp the upstairs. Thanks

Because of the "double Y", NONE of the fixtures on that connection are vented.

Vents prevent the traps from siphoning out and allowing sewer gases to come into the home. Vents are required per code. Don't sacrifice your health. Plumbing needs to be done properly and have cleanouts where desired in case of stoppages. good luck.

Updated sketch : [i.imgur.com]



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get rid of the 3 x 3 x 2 side inlet ell. use a long sweep 90 and install a 2 inch "Y" into the shower drain. use the branch of that "Y" as a vent for the toilet and shower. then 18 inches above the floor put a 2 x 1 1/2 san tee for the lav.
classic wet vent.. see here. this shows 1 1/2 for tub but yours will be 2 inch for shower.

Updated [i.imgur.com]

A Long Sweep 90 Street may just barely fit in the space behind the stack, but it is hard to be certain without fitting everything up. Is a standard elbow not allowed?

if you can't fit a long sweep 90 then just use a regular drainage 90. it will be fine. as for the rest of the drawing, well, it looks like the way I would have drawn it.
first floor bath is properly wet vented using only a single 2" vent and a minimum number of fittings.
second floor toilet and shower drain into a side inlet san tee.
the second floor lav is stack vented.
very nice job..

Thanks for your help Packy



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