No you can not.
Hello again wise plumbers...
As I've posted recently, I'm in the starting stages of a basement remodel, to include a new bathroom. To do so requires an ejector, and some other concrete cracking/excavation - for the toilet and shower, at least.
In an effort to minimize the concrete work, the following struck me: Can I have a shower and laundry next to each other; the shower with a 2" trap, and its own vent in the wall bounding the shower, and the laundry with a 2" standpipe and trap, and its own vent, with the drainage of the laundry then flowing via a santee into the vent pipe of the shower?
No you can not.
Is that because the laundry hook-up makes the shower a wet vent?
It's not technically a wet vent (as I understand it), that's where multiple fixtures are attached to the same drain line that may only have one vent. On your proposed situation, the only vent is being asked to be a drain...not the same thing. Once a vent becomes a vent, it must always remain a vent - you can't use it as a drain.
Important note - I'm not a pro
Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013
You've already made it easy by deciding to have the laundry close to the bathroom, now don't make it hard by trying to use a vent as a drain.
You're going to have to remove concrete no matter what, why not do it all once and do it right?
Your 2nd drawing will work and meet code.
Thanks everyone - expert advice much appreciated.
The other day I posted a diagram that was generally well received, including wet venting a lav into the toilet drain. A detail of that drawing is below.
I'm trying to understand - it's OK to take a lav drain and drop it down the toilet's vent, but not to do the analogous and drop the laundry's drain down the shower's vent? Is that correct? Is it because the lav/toilet/shower are all a 'group' that are allowed to wet vent together, and this excludes the laundry?
NO! It is because the washer is a "high volume and flow" device, and its water going past the shower drain connection, WITHOUT a vent, could aspirate the water from the shower trap. It would NOT be vented, because you have the shower vent occulded by the water flowing from the washer. IF you could do it, you would NOT need the washing machine vent in the first place. I have one customer who has a "high flow" device connected to his toilet's vent, apparently because it was the "easiest" place to connect it, and every time water discharges it sucks all the water out of the toilet.
Last edited by hj; 08-23-2011 at 05:57 AM.
Licensed residential and commercial plumber
Why you keep insisting on using the vents as drains?
I'm not insisting on anything - I'm just trying to learn.
I suppose I come up with some of these strategies because I don't like concrete work, and I'm trying to minimize it. It's dusty and dirty, the debris is heavy - I just don't enjoy doing it as much as framing or running pipe or installing windows. I was looking for the design scheme for this bathroom that would allow the least amount of concrete break-up and refilling, that's all.
It also seems that using vents for drains - like the lav into the toilet - was OK. I didn't know how far this extended. I totally understand now about the high flow nature of the original scheme above not being a good or workable idea.