Adding a new bathroom and replacing corroded copper drainage pipes

[maprice]

First like to say this forum is amazing and has been super helpful!

I'm in West Des Moines, Iowa and we are under UPC 2015.

I'm adding in a new bathroom and making sure I've got all the plumbing up to snuff and wanted to run this past some experts to make sure my plan will work.

Our other bathroom and kitchen are on the same branch and the pipe literally keeps springing leaks (luckily not by the toilet). It is old and a weird hodge-podge of 1.5" and 2" copper that finally ties into the toilet 3" copper before going into the main stack.

While I'm installing the new bathroom, I'd like to go ahead and replace all that corroded, crappy copper with PVC as it'll solve the recurring leaks and it'll make plumbing the new bathroom quite a bit easier.

So my first question is if I have the plumbing for the new bathroom set up correctly. Hopefully you can read my chicken scratch, but basically I have the shower 2" drain feeding into a 3" WYE combo which hooks to the toilet and exits as 3 inches. The vent ties in within 5 feet of the shower trap. I do need to add a sink to the drawing, but it is around a corner and I couldn't figure how to not make it look bad, but I am planning on adding that in before the shower with another WYE combo. Also I was thinking about adding a cleanout to the 3" section before the toilet ties in. Is that necessary or a good idea?

The second question about replacing the existing copper is if it's okay to tie another sink and bathtub to the 3" line I'll be running all the way back to the soil stack? And it currently connects through the other toilet's 3" line to the soil stack, can I replace that copper 3" WYE to 2" (current drains I'll be replacing) with a Fernco 3" WYE (https://www.homedepot.com/p/3-in-x-3-in-x-3-in-Flexible-PVC-Tee-PQT-300/100372310) or do I need to do a 3" copper WYE and attach the PVC to the copper WYE with a coupling?

Thanks so much for any help/suggestions!

 

[Reach4]

I suggest you search the forum, using the search box above, for the term "bathroom group".

You will find that the examples of good ways have the fixture venting before the toilet.

 

[Sponsor]

 

[maprice]

I suggest you search the forum, using the search box above, for the term "bathroom group".

You will find that the examples of good ways have the fixture venting before the toilet.

Oh shoot I totally forgot to put that in my post, the shower and sink are tied to one 2inch dry vent that hooks up to the same 2 inch vent in the attic space. That's all on that wall that I couldn't really draw in there very well. Let me update that picture a little. (nevermind I screwed up my pretty drawing, but basically there's a shared 2 inch pipe running up a wall to the attic to hook into the roof vent that is shared between the sink and the shower. The toilet is on the "main" vent line that runs down to where it is in my drawing. The shared sink and shower vent ties into it before it exits the roof though. Or at least that's my plan based on where that existing vent is).

I did see the wet venting 3/4 bath diagram by searching that though, thanks!