Bathroom Group and Laundry DWV Question

[tshootz]

Hello all,

I've been looking through some other posts and the 2018 IPC, Counties current code, and think I know the answer, but wanted to get some additional confirmation on this topic.

In our new construction we have a bathroom group on the first floor, lav, WC and shower in one room and the other room on the other side of the wall is a laundry room/mud room. From lowest to highest drain it goes like this: lav, laundry stand pipe, WC and then shower drain. The plumber was planning to tie the dry vent into the laundry standpipe or the lav and I don't believe this is to code per section 912 of the 2018 IPC but would love to get an opinion from another party.

Thanks in advance for the help!

 

[John Gayewski]

Huh? The dry vent can connect to anything it wants as long as it's above the fixtures and the size is correct.

Maybe I'm not understanding your question.

 

[Sponsor]

 

[tshootz]

Huh? The dry vent can connect to anything it wants as long as it's above the fixtures and the size is correct.

Maybe I'm not understanding your question.

Biggest question is can the laundry standpipe drain be tied into the bathroom group drain or is it supposed to tie into the main drain downstream of the bathroom group? 912 talks about wet venting and how only fixtures within the bathroom group can tie into the wet vent and any other fixtures discharge downstream of the wet vent.

 

[John Gayewski]

No you can't drain a laundry into a wet vent. Laundry should be downstream and have it's own vent.

 

[tshootz]

That's what I thought. Thanks for the confirmation!

 

[tshootz]

No you can't drain a laundry into a wet vent. Laundry should be downstream and have it's own vent.

One other quick question I have around the venting for a wet vent if you could help me understand this. In the same layout, removing the laundry, the dry vent ties into the lav and upstream of the lav is a wc and a shower. Section 912.2.1 talks about the dry vent connection for a wet vent and says no more than one wet vented fixture can discharge upstream of the dry vent fixture connection. If the only dry vent connection is the lav does that mean I can only have either the wc or shower, but not both, discharge upstream of that dry cent fixture connection?

 

[John Gayewski]

Yes. Usually from bottom to top it would go toilet, shower then lav with the lav drain being being the wet vent everything then the lav vent is a dry vent. Some layouts require different placement of the dry vent but in the ipc there's a limit of what can be upstream.