Drain size for washer in Canada

Discussion in 'Canadian Plumbing Code Questions' started by MIKE007, Aug 26, 2013.

  1. MIKE007

    MIKE007 New Member

    Messages:
    18
    Location:
    Montreal
    My vertical drain is 1 1/2. There is a dishwasher + kitchen sink on the first floor and a washing machine in the basement connected trough a back flow valve after the p-trap. I newer used both washing machines at the same time. Is this diameter fine for both machines at the same time or I need 2"?

    Thanks
  2. dj2

    dj2 Member

    Messages:
    409
    Location:
    California
    You need 2". Why is your drain 1-1/2"?
  3. mikeplummer

    mikeplummer Plumber

    Messages:
    190
    Location:
    Ontario, Canada
    maximum hydraulic load (fixture units) drained to a 1-1/2" soil or waste stack - 8FU
    maximum fixtures units from any one storey drained to a 1-1/2" soil or waste stack - 5FU

    kitchen sink = 1.5 FU
    dishwasher = if separately trapped with 1-1/2" trap - 1FU if connected to sink or garbage disposal - 0FU
    clothes washer = 1.5FU with 1-1/2" trap

    assuming all piping and venting is proper - your arrangement meets code requirements
  4. MIKE007

    MIKE007 New Member

    Messages:
    18
    Location:
    Montreal
    Thank you for your answer.
  5. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,338
    Location:
    Yakima WA
    I believe Canadian codes are different in that they have not upped the drain sizes as the US has. Your 1-1/2" may be legal, but 2" sure would be better.
  6. Bill Shack

    Bill Shack 30years plumbing 10years plumbing inspector

    Messages:
    45
    Location:
    montreal quebec Canada
    I disagree, The pipe must be at least 2 inches, Further the Quebec amended canadian code is about to change so that all laundry machines connection are minimum 2 inches.
  7. mikeplummer

    mikeplummer Plumber

    Messages:
    190
    Location:
    Ontario, Canada
    the Ontario Plumbing Code is also changing the minimum drain size for a laundry pipe to 2"
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