Help on bathroom plumbing wall configuration

[larsonist]

I’m repiping my house and making some changes to the fixture locations. I was wondering if someone could take a look at my sketched isometric for vent and drains to see if I’m grouping the right items on the plumbing wall between the two bathrooms and to help identify any concerns (my city follows 2015 UPC). I’ve included a sketch of my floor plan to help shed light on what my setup will be. The walls are 2x4s, except the plumbing wall between the two bathrooms which is 2x6.

A secondary question is my plumbing wall runs parallel to my main sewer line but 2 feet offset. My isometric doesn’t account for this, but in the floorplan I put a little indicator where the sewer line enters the foundation wall (it’s a one story house with crawl space underneath). So I’m also trying to determine if each drain should go down and over to the main line or have everything connected to a secondary waste line directly underneath the plumbing wall that runs parallel and then cuts over and connects with the main sewer line?

Thanks for any help you might give me!

 

[Terry]

I would be inclined to run the main line under the plumbing wall unless you have a beam there for support.
The toilet would wye off from there.
The shower would wye off before the tub and vent for tub/shower.
The single lav would wet vent the toilet.
The double lav has it's own vent.

Many ways to run the lines below. Hey, it's not set in concrete.
Cleanouts at end of lines. The washer cleanout I like in the wall above.

 

[Sponsor]

 

[larsonist]

I would be inclined to run the main line under the plumbing wall unless you have a beam there for support.
The toilet would wye off from there.
The shower would wye off before the tub and vent for tub/shower.
The single lav would wet vent the toilet.
The double lav has it's own vent.

Many ways to run the lines below. Hey, it's not set in concrete.
Cleanouts at end of lines. The washer cleanout I like in the wall above.

Hey Terry,
Thanks for the reply. I’m trying to understand your recommendation but I’m getting a little lost.

Off the start one thing I figured out when I went back underneath is there is a secondary line which would be better to run my washer to, so that’s no longer in this particular equation.

Alright, I’m getting hung up on a few things:

1) you mention the shower and tub being separate wyes, is there a reason why I shouldn’t consider a double wye combo and get them both with one drain and vent since they’re basically across the wall from each other? (Seen In my new badly drawn diagram)
2) You mentioned wet venting the toilet with the single lav, I’m not sure how this would work, would the lav have a longer trap arm teeing into the vent and above the drain at the toilet?
3) You mentioned combining the double vanity on one drain, but the trap arms would run in the same area as the single lav on the other wall, so I’m trying to understand how to make this fit within the wall?
4) The plumbing wall runs parallel with the floor joists, and is about 2 feet off from the main line exit point through the foundation wall, so would adding 2- horizontal 45’s with a straight stretch between be gradual enough to get it back over to my needed exit spot? It’s about 6 feet of wiggle room between the end of the shared plumbing wall and the exit spot?