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  1. #1
    Lisa Brown's Avatar
    Lisa Brown Guest

    Default Air Gap for dishwasher required?

    Inspection Referral SOC

  2. #2
    Join Date
    Mar 2007
    Location
    Mahtomedi, Minnesota
    Posts
    92

    Default Re: Air Gap for dishwasher required?

    P2717.1 Protection of water supply. The water supply for
    dishwashers shall be protected by an air gap or integral
    backflow preventer.

    Fred Comb, ACI
    Mahtomedi, MN
    www.homeinspectionsofmn.com

  3. #3
    Join Date
    Mar 2007
    Location
    Columbus GA
    Posts
    3,746

    Default Re: Air Gap for dishwasher required?

    Lisa in the OP, did not state if she is asking about the air gap for the supply side, or tn air gap for the drain side. However since the supply side is fixed by the manufacturer and cannot be changed I think she is asking about the drain side.
    The 2006 IRC does not require an air gap on the drain side. But she is wanting to know if Washington state has a requirement for an Air gap on the drain side.
    I cannot answer that question.

    FWIW
    A little information on DW's
    The IRC requires the SUPPLY side to be protected by either an air gap, or an integral backflow preventer.
    AFAIK all modern DW are protected by an air gap for the supply.
    The water supply connects to the solenoid, runs up the side of the tub above the threshold of the door, and empties into the tub. This meets the requirement for an air gap.
    I do not know of any current DW that uses a backflow preventer on the supply.
    Note: I said I do not know, not there is not one.

    The IRC does not require an Air Gap on the drain side. However some States and local AHJ's may require an air gap on the drain side.

    An Air Gap on the drain side is not built into the DW, ever.
    Some DW's do have a "High Loop" built into the design.
    If the DW has the high loop built in it can only be confirmed by removing the DW. Even if the DW does have the high loop built in, the IRC requires the drain line to be securely fastened to the underside of the counter.
    This requirement eliminates any confusion as to if the DW has a built in high loop or not. The drain line must be fastened to the underside of the counter.

    2006 IRC

    P2717.1 Protection of water supply.
    The water supply for


    dishwashers shall be protected by an air gap or integral
    backflow preventer.
    P2717.2 Sink and dishwasher.


    A sink and dishwasher are permitted


    to discharge through a single 1


    1/2-inch (38 mm) trap.


    The discharge pipe from the dishwasher shall be increased to a
    minimum of


    3/4 inch (19 mm) in diameter and shall be connected


    with a wye fitting to the sink tailpiece. The dishwasher
    waste line shall rise and be securely fastened to the underside of
    the counter before connecting to the sink tailpiece.
    P2717.3 Sink, dishwasher and food grinder.


    The combined


    discharge from a sink, dishwasher, and waste grinder is permitted
    to discharge through a single 1


    1/2 inch (38 mm) trap. The


    discharge pipe from the dishwasher shall be increased to a minimum
    of


    3/4 inch (19 mm) in diameter and shall connect with a


    wye fitting between the discharge of the food-waste grinder
    and the trap inlet or to the head of the food grinder. The dishwasher
    waste line shall rise and be securely fastened to the
    underside of the counter before connecting to the sink tail piece
    or the food grinder.


    Last edited by Rick Cantrell; 03-14-2011 at 06:29 AM.
    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

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