trap tailpiece minimum length

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by stevenrobertburke, Feb 8, 2011.

  1. stevenrobertburke

    stevenrobertburke New Member

    Messages:
    4
    Location:
    Olympic Valley, CA
    Hi,
    What is the minimum trap-to-vertical waste drop for a 2" tailpience?

    We are in a tight situation for two separate situations. one situation is a shower drain, the other is a laundry drain. Both are 2" ABS and will be located in a crawlspace.i

    Thank you, Steve
  2. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    I don't think there is any minimum. You could have the trap arm parallel to and in contact with the base of the shower, sink, etc.
  3. stevenrobertburke

    stevenrobertburke New Member

    Messages:
    4
    Location:
    Olympic Valley, CA
    Thank you Jimbo,
    My intent is to avoid an "S trap" Is it ok to go from a 2" ABS trap to a 90 el (outlet is facting down) fitting into waste stack?
  4. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,248
    Location:
    Land of Cheese
    The limiting is the distance from the trap to the vent.
  5. shacko

    shacko Master Plumber-Gas Fitter

    Messages:
    561
    Location:
    Rosedale, Md
    If I read you correctly that IS a s-trap!
  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,689
    Location:
    Cave Creek, Arizona
    quote; Is it ok to go from a 2" ABS trap to a 90 el (outlet is facting down) fitting into waste stack?

    That is the definition of an "S" trap, so you would be creating one, not avoiding it. And the way you describe it, there might also NOT be a vent for the drain.
  7. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Under the UPC the developed length ( weir of trap to vent opening) minimum length = 2 X diameter.So your length can be quite short, provided it does not drop without a vent opening
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