Bathroom Group DWV / Wet Vent Question

[Ryan Smith]

I'm adding a second bathroom to a late 1800s farmhouse. I have some obstacles that limit where I can put the WC, lav, and shower and am looking for some feedback on DWV options. I'd like to do a single lav vent, using that to wet vent the rest of the bathroom group.

I've spent a couple days researching, but still have a couple questions. The first is if the WC needs to be the last to enter the wet vented waste line or if it can land between the lav and shower. I also can't seem to find if a wet vent can "turn" around a 45 horizontal-to-horizontal and still maintain the vent.

Here are the best two options I've come up with so far for a single lavatory (originally planning double lav, but didn't update picture yet), toilet, and shower. Plan A saves some pipe and fittings, but has the WC before the shower. Option B results in about a 7 ft developed length on the WC branch, but it looks like Wisconsin code allows this @ 1/4"/ft. Please critique and any suggestions are greatly appreciated. I'm pretty locked into the vent location and final waste connection, but can move anything in between. Location is Wisconsin.

 

[James Henry]

If there is nothing draining into the stack you are tying into and is strictly a dry vent going through the roof, then you might consider a "side inlet santee".

 

[Sponsor]

 

[Ryan Smith]

If there is nothing draining into the stack you are tying into and is strictly a dry vent going through the roof, then you might consider a "side inlet santee".

Hi James - thank you for the reply! I should have detailed that red circle better. Unfortunately it isn't an existing stack. It's just the only location where I can get a new 3" line from the second floor down to the basement. I was planning on having a 90 there to transition from horizontal to vertical. Unfortunately I have obstacles above at that location, so I have to do the vent over by the lavatory.

 

[wwhitney]

1) You need to try to decipher this part of the Wisconsin Plumbing Code. I think it means the WC doesn't have to be last, but I'm not confident, being not so familiar with the Wisconsin code.

https://docs.legis.wisconsin.gov/co...ngs_and_environment/380_387/382/iii/31/13/b/5

2) Sure, the horizontal wet vent can turn 45 or 90 degrees, it doesn't have to be straight.

Cheers, Wayne

 

[James Henry]

Hi James - thank you for the reply! I should have detailed that red circle better. Unfortunately it isn't an existing stack. It's just the only location where I can get a new 3" line from the second floor down to the basement. I was planning on having a 90 there to transition from horizontal to vertical. Unfortunately I have obstacles above at that location, so I have to do the vent over by the lavatory.

Yea, theirs always something missing. Your code doesn't specifically state that the water closet has to be last so one would assume it doesn't.
Check with your code official, your layout might be permissible.