Wet venting lav and shower with dry vent downstream toilet Oregon

[PlumbHomebody]

Just checking if folks think my plumbing plan will work. I am in Oregon and under UPC 2021. Adding a kitchenette and bath to shop. I need a minimum 3” vent exiting from roof according to my understanding so what I am planning to do is to wet vent the bath lav and shower together and then downstream from there dry vent the WC/toilet with a 3” pipe through the roof which I will tie the 1.5 inch dry vent portion of my wet vent back into. I also have a washer machine that I would like to tie into the wet vent with shower and lav which are all on 2 inch drains.

Lastly my kitchenette drain is tying into the 3 inch drain with a 3x3x1.5 low heel close to where the drain exits the shop and will be vented and tied in with the 3” dry vent for the toilet near the roof exit.

I attached a rough sketch here.

Many thanks for any feedback.

 

[wwhitney]

Comments based on the UPC, as I haven't checked for any Oregon specific amendments:

- As long as the shower trap to the 2" wye where the lav joins is at most 5' horizontally and 2" vertically, the lav and shower are fine.

- The washing machine standpipe trap will need a separate dry vent that connects back to the 3" dry vent; it can't be wet vented.

- The WC is dry vented, so that's good. Note that the dry vent takeoff needs to be a wye or combo, and it needs to come off the top half of the drain, and it needs to rise (at most 45 degrees from plumb) until at least 6" above the WC flood rim. No horizontal dry vents below the floor.

- The kitchen drain needs to be 2" starting at the point of the vent takeoff (only the trap arm can be 1.5"). I'm unclear how you are connecting the kitchen drain and the WC drain, but if the kitchen drain is coming in vertically, the WC coming in horizontally, and the combined drain leaving vertically, then yes, a 3x3x2" low heel inlet quarter bend is effectively a 3x2x3 san-tee and can be used as such.

Cheers, Wayne

 

[Sponsor]

 

[PlumbHomebody]

Wayne,

Thanks for this reply. Very helpful!

On the shower and lav being wet vented together and I am within the measurement you specified for trap to vent distance and for the pipe fall.

I wish I could do an AAV for the washer but as far as I understand it’s not allowed in UPC.

I will do a wye on its back/wye above 45 for the toilet dry vent and take the pipe straight out the roof.

The kitchen drain will drop vertically into the drain from toilet via the low heel. I thought that the kitchen drains only had to be sized at 1.5 though.

Thanks for taking your time to answer!
Jo