Laying out Rough-in for new Bathroom in Slab

I would appreciate help laying out a new bathroom I'm building off the master bedroom into the garage on a slab. I'll be cutting through about 20 feet of slab to reach the main, outside, 4 feet underground. I've done a lot of home plumbing but am stuck designing the correct layout for this bath. The fixtures cannot be moved as I have very little space to work with and don't want to lose the garage for parking. I would like to lay it out like #1 but read something about not placing a toilet upstream of other appliances, so I came up with #2.

I don't know if either of these will work and would appreciate any feedback.

Thanks

If we could not connect a toilet "upstream" of other fixtures, builders would be severely limited as to how they could design their bathrooms. Either drawing is workable as far as the concept is concerned, (I might not do it either way, but that is a personal preference). HOW you actually install the piping is the important thing.

You can use the lav to wet vent the toilet if you have 2".

The shower has to be vented before it hits the downhill side of the toilet waste. If you have wyed off for the shower and vented between the 3" and the shower trap.

Since he has "depth", he could install a 3x3x3x2 side inlet tee under the floor at the lavatory. The 3" branch would point to the toilet, and the shower would connect to the 2" inlet. The sink would connect to a 2x1 1/2" tee in the "vent" riser.

When you say "The shower has to be vented before it hits the downhill side of the toilet waste" do you mean the shower vent physical elevation must be higher before it turns vertical than the beginning elevation of the toilet discharge line?

Here's another drawing to reconfigure the lavatory drain from the previous drawings:

Are you saying to run the main 3" line to the 3x3x3x2 side inlet tee near the lav and branch out from there to all fixtures? That's a cool fitting. Thank you to all.

Not 'near" the lav, but centered behind it so the riser and tee are right in line with it.

Ok, I get it. So I can tee off the 2" side to run the lav and continue vertically for VTR. So the toilet would wet vent off the lav? Is the 2" vent off that fitting enough for all 3 fixtures for the VTR or would a shower vent need to be tied into that riser?

I believe San Jose is UPC and am thinking I need a vent for the shower to tie into the VTR. I can also put a C/O there. How does this look? Have mercy on sparky. This is short circuiting my brain:



Thank you...Dominick