Drain size for tub/shower combination

Discussion in 'Shower & Bathtub Forum & Blog' started by Home Girl, Nov 23, 2009.

  1. Home Girl

    Home Girl New Member

    Messages:
    3
    Location:
    Vacaville, CA
    I am reading that the tub drain should be 1 1/2" while a shower drain should be 2". If a tub/shower combo is installed, can a standard tub drain be used, or does that require a larger shower drain?
  2. FloridaOrange

    FloridaOrange Plumbing Designer

    Messages:
    1,317
    Location:
    SW Florida
    What do you mean by tub/shower combo? Tub with a shower head? If so the 1-1/2" drain will work. The idea is that the tub can provide holding space for water if the drain is slow, a shower doesn't offer much if any holding before you overflow the curb.
  3. The smaller size drain works.

    It also works for showers too, and that used to be the size required by "Code" too. I think that bigger houses and longer distances are the reasons why its size was increased to 2".
  4. Inspektor Ludwig

    Inspektor Ludwig Journeyman/Inspector

    Messages:
    167
    Location:
    In the good ol' UPC
    Yes, you can have an 1 1/2 drain for tub/shower combo.
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,812
    Location:
    Cave Creek, Arizona
    1 1/2"

    You are too young to remember when a shower was permitted to have a 1 1/2" drain. I am also.
  6. FloridaOrange

    FloridaOrange Plumbing Designer

    Messages:
    1,317
    Location:
    SW Florida
    Florida used to require all under slab plumbing to be minimum 2". Now they don't, along with allowing CVPC (with joints) underslab....
  7. plumbergreg

    plumbergreg New Member

    Messages:
    11
    Location:
    Ontario, Canada
    The sizes in the code are the minimum size not the required size;)
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