Bathroom Vent

[jakeinsouthcarolina]

Hello - new to forum. I’m trying to get some education on venting - which always confuses me a bit. I’m building a small detached sleeping room with a small bathroom. My plumbing plan is something like pictured here. My question is whether I need the vent lines at all since everything is so closely coupled or whether I can allow the other drain lines to function as the vents if I use 3” on everything. This isn’t a code issue for me (no permits or inspections required)but just a function issue. For scale - it is 13 feet across the whole plan making the toilet and shower drain about 5.5 and 4.5 feet from the main drain line leading to the vent stack.

Waste lines in red - possible vent lines in green. This will be under slab

thanks in advance for any help you can provide

 

[Stuff]

You only need a single vent at the lav; it is called wet venting. 3" is only needed for the main and toilet branch. The rest should be 2"

 

[Sponsor]

 

[jakeinsouthcarolina]

You only need a single vent at the lav; it is called wet venting. 3" is only needed for the main and toilet branch. The rest should be 2"

thank you very much - appreciate the reply. This is what I was thinking. The vent lines looked redundant.

 

[Terry]

All horizontal fittings there should be wyes or combo fittings.
The lav run with 2" can wet vent both the shower and the toilet.
If this is on the first floor where you need an end of run cleanout, then under the lav would be a good spot.

 

[jakeinsouthcarolina]

Thanks for the additional detail. It is in fact on the first floor