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

Discussion in 'IPC Plumbing Code Questions' started by leet, Sep 11, 2013.

  1. leet

    leet New Member

    Messages:
    5
    Location:
    Charlotte, NC
    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.

    current.jpg move laundry drain - add 2 sinks to same drain.jpg

    Thanks for your help,

    Lee
    Last edited: Sep 11, 2013
  2. Terry

    Terry Administrator Staff Member

    Messages:
    15,010
    Location:
    Bothell, Washington
    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.
  3. leet

    leet New Member

    Messages:
    5
    Location:
    Charlotte, NC
    Okay, thanks Terry - working on plan "B"
  4. leet

    leet New Member

    Messages:
    5
    Location:
    Charlotte, NC
    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
    mbath with vents.jpg
  5. Terry

    Terry Administrator Staff Member

    Messages:
    15,010
    Location:
    Bothell, Washington
  6. leet

    leet New Member

    Messages:
    5
    Location:
    Charlotte, NC
    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

    mbath with vents on sketchup.jpg

    Last edited by a moderator: Sep 16, 2013
  7. Terry

    Terry Administrator Staff Member

    Messages:
    15,010
    Location:
    Bothell, Washington
    [​IMG]

    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.
    Last edited: Sep 16, 2013
  8. leet

    leet New Member

    Messages:
    5
    Location:
    Charlotte, NC
    genius! thanks so much for your help! Lee
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