double bathroom sinks and washing machine through 2 inch drain - no vent - okay?

Hi,

Is it permissible and advisable to drain two bathroom lavs and a washing machine through a single 2 inch drain pipe with a run of less that 4 feet to the stack with no vent? The stack in my images also has a bathtub drain and toilet tied to it - all of this on the ground floor with no other drains or vents on this stack. I have provided two images - a photo "current" and the other image is a mock-up of my plan. I intend to move the washer drain over (laundry room is behind this wall) and add two bathroom sinks in place of a single sink.



Thanks for your help,

Lee

The washer needs a vent, the lav needs a vent and the other lav needs a vent.
Those three vents can tie together at 42" above the floor.

You need a wye fitting or combo with waste going from vertical to horizontal. A Santee is not allowed in that position.

A washer does a good job of siphoning traps.
That's why they are "never" allowed in a wet vent system.

Okay, thanks Terry - working on plan "B"

I created a new plan with a vent for the washing machine and a shared vent for the 2 sinks - using 2" pipe for all drains and vents. Do I need the washer vent in this setup? Can I share one vent with 2 sinks? Please refer to my mock-up below and let me know what you think.

Thanks again, Lee

It's getting late on Friday.
The last drawing shows s-traps on the lavs.
The vent comes off the "top" of the trap arm, not below it.

Helpful Plumbing Hints for Residential Construction by Bert Polk Plumbing Inspector Lincoln County

First, the link you shared was very helpful - thanks!

Would you mind reviewing the diagram I created in response to your feedback? It is intended to show the flow of the drains and vents but not the fitting details. All pipes are pvc: 3" stack, 2" drains, 1.5" vents, and 1.25" sink drain traps. I would have set up both lavs like the one on the right but there is no room in the wall to cross a drain and a vent.

Thanks again for your help,

Lee

This drawing does not work
Terry

Click to expand...

The revent is at 42" or higher off the floor.
The washer standpipe is at least 18" long.
I typically rough the lavs at 20" from the floor with a 32" counter.
The washer box works well at 48" to the top of the box. It can be lower than that, but the standpipe must be 18" at the min. I buy the washer shutoffs with hammer arrestors.

genius! thanks so much for your help! Lee