Wet Vent / DWV Design Question

[chad_w]

Have a question regarding a DWV system a plumber installed in a new build for me which utilizes a wet vent. Apologies for the crude drawing which does not accurately show length, but schematically it is correct. Key information:

1) PVC DWV System on 2nd story and spans 2 rooms. Bathroom and Utility Room. Below is a garage.
2) 3" main stack line (vertical)
3) WC drain line is 3" from flange to stack, all other drain lines 2"
4) SH = Shower, Lav = Lavatory, WM = Washing machine box
5) All fixtures in bathroom, with exception of WM which is in utility room
6) WM is dry vented with 1 1/2" vent line and 2" drain line.
7) SH, Lav and WC are horizontally wet vented (2" line) with vertical dry vent at LV that is 2"

I believe the system has two code violations, labeled with a 1 and a 2 on schematic:

Violation #1: For the short portion (<12 inches) of the wet vent that is downstream of the LAV, SH, and WM but upstream of the toilet (labeled with a 1 on diagram), the total DFU is 5 (Lav = 1, SH =2, WM = 2). 5DFU for a wet vent requires > 2" pipe, but plumber used 2". (I am not sure if 2.5" or 3" is required).

Violation #2: The WM, which is dry vented (required as it is separate room from bathroom group), should tie into the drain system downstream of the wet vent. As the schematic shows, the current design has it tied into the wet vent portion of the DWV system.

I would appreciate it if the experts on this board can set me straight on whether my assessment is correct and the system does have 2 code violations, or if this design is ok.

Thanks

Chad

 

[Stuff]

Your assessment is correct for IPC. What matters, though, is what your local codes allow and what the inspector says.

 

[Sponsor]

 

[chad_w]

Forgot to add that we follow 2015 UPC here. I checked for any local amendments to UPC for wet venting, and there aren't any.

I agree that in the end all that matters is what the inspector wants. We failed our first rough inspection because the original design by the plumber had the WM tied into the drain system 6 inches after the trap for the shower, which put it inside the wet vent bathroom group. The inspector said that was not allowed (which I agree with), and gave us options to fix. The schematic posted is one of the layouts he said was acceptable, but still has the WM draining into the wet vent (ie. not downstream)

I believe that the solution he gave us still does not meet UPC code. My concern is that upon re-inspection the next inspector that shows up will cite these two items as violations. Also, even if they pass it, I want to make sure it is built "correctly" as I don't want issues down the road.

 

[Stuff]

Simple option is to tie WM in downstream/left of the toilet/vent connection.

 

[chad_w]

Agreed. Space is quite limited, however. Here are a few pics. 3" stack connected to toilet through 2 long sweep 90s. 0677 and 0678 pics show stack with the 2 90s. 0679 pic shows how much space I have to work with between the 90s. Best case is maybe I could stick in a 3"wye + 1/8 bend.

The other option I was thinking of was to add a dry vent to the WC. and tie it to the LAV dry vent (which is the dry vent for the wet vent). That would essentially end the wet vent at the shower connection and would eliminate both violations I believe.

 

[Stuff]

Most would kill to have your "limited" space. It does look like fitting hell, though. Might be easiest to rip it all out and start fresh since you have access. I never like seeing 180s on drain pipes so would come up with a new design.

 

[chad_w]

That 180 for the shower drain was the inspector's solution