Double (triple) vanity sink plumbing

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by tvizzle, Jun 29, 2020.

  1. tvizzle

    tvizzle New Member

    Joined:
    Oct 10, 2016
    Location:
    Washington
    Hey y’all!

    Is there a legal way to add a second vanity sink to this?

    [​IMG]


    There’s an adjoining bathroom on the other wall, that’s the lav on the right. It’s a 60 inch wall and would be awesome to add another sink!
     
  2. Terry

    Terry Administrator Staff Member

    Joined:
    Aug 17, 2004
    Occupation:
    Plumber
    Location:
    Bothell, Washington
    You have a 1.5" pipe there for two lavs now. Code now wants 2" for two or more lavs before the cross fitting.
    Below Is how I make a 1.5" work for two lavs.

    [​IMG]

    It's code if it's 2" to the wye.

    [​IMG]

    With 2" and a double fixture fitting.

    QUESTION: In the original picture with the galvanized steel pipes, what is below that floor? Normally you can run it back to a 2" cast iron hub and from there you can run a new 2" pipe using a pipe donut.
     
    Last edited: Jun 29, 2020
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  4. tvizzle

    tvizzle New Member

    Joined:
    Oct 10, 2016
    Location:
    Washington
    Under the bathroom is either 3” or 4” cast iron, Id have to double check. It serves 4 bathrooms, so my money’s on 4”. I could definitely run 2” back to the hub, the galvy is not in good shape anyways.

    Should I vent the double fixture even with 2”?
     
  5. Terry

    Terry Administrator Staff Member

    Joined:
    Aug 17, 2004
    Occupation:
    Plumber
    Location:
    Bothell, Washington
    All plumbing needs venting. Have you ever noticed all those plumbing vents through the roofs in your neighborhood?
    Venting breaks the siphon and prevents the p-traps from being sucked dry allowing sewer gas from entering the home. The lavs can be vented with 1.5" and the waste side where they combine is 2"

    [​IMG]
    This video shows how to shot gun a beer. Drinking from a can with two holes, one to drink from and the other hole allows air to pull through.



     
    Last edited: Jun 29, 2020
  6. tvizzle

    tvizzle New Member

    Joined:
    Oct 10, 2016
    Location:
    Washington
    Right! *shotguns beer*
    I mean somethings still gunna be wet vented, kinda like this: upload_2020-6-30_4-17-1.jpeg

    right? The double fixture t needs a vent loop back to the main stack.
     
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