Dishwasher (re-)installation, not near sink

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by CM_George, Jul 17, 2020.

  1. CM_George

    CM_George New Member

    Joined:
    Jul 17, 2020
    Location:
    Wisconsin
    I am in a condo with a slab foundation and a first floor kitchen. I somewhat recently had my kitchen cabinets flooded out from my dishwasher's drain overflowing, and I'm looking for advice to try and prevent it from happening again.

    The kitchen is as shown in the attached drawing. As you can see, the dishwasher is nowhere near the sink. When the dishwasher was originally installed, they ran a dedicated standpipe drain and dedicated water line to the dishwasher, as shown in the attached photo. (Yes, the slope of the horizontal PVC pipe is wrong; there were J-hooks attached to the wall holding it at the proper angle, but the pipe was not properly placed into the hooks. This was almost certainly the source of the problem.)

    Being that the drain and water feed are behind the dishwasher, the drain overflow wasn't able to be caught and addressed before serious damage was caused to the cabinets and walls. I would like to address this situation so that this doesn't happen again.

    I do plan to put a leak sensor and an automatic shutoff on the water feed. While that would catch and alert me to a drain overflow, it doesn't really fix the problem.

    I considered relocating the dishwasher to be closer to the sink so that I could eliminate the standpipe drain and "close" the drain system for the dishwasher, but given the angle wall that the sink is on, putting it any closer to the sink would make it difficult to open and use the dishwasher.

    What is my best situation?
     

    Attached Files:

  2. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    I think you are saying that you would like to keep the standpipe pretty much where it is now, but you want it to accept water better.

    Not related to that, but to a potential smell, how long is the path along the pipe after the trap? Not the shortcut, but the total distance along both walls.
     
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  4. CM_George

    CM_George New Member

    Joined:
    Jul 17, 2020
    Location:
    Wisconsin
    I would prefer if there was a way to eliminate the standpipe and "close" the dishwasher's drain system (e.g. run it to the sink), but I'm not seeing one.
    I don't have those the exact measurements right here, but based on the floor plan measurements posted above, you're looking about 45" (approx.) (Edit: that's wrong, I forgot the section on the other wall. I'll get that measurement shortly.)
     
    Last edited: Jul 17, 2020
  5. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Since the dishwasher drain is pumped, you can go a fairly good distance along/through the walls. Looks like maybe 150 inches. Is that about right? Dishwasher makers sell extensions such as https://www.homedepot.com/p/Bosch-7...Kit-for-Bosch-Dishwashers-SGZ1010UC/304829328, but it seems to me that a smooth pipe could make a longer path without problem. I am not a plumber.
     
  6. wwhitney

    wwhitney Active Member

    Joined:
    Mar 17, 2019
    Location:
    Berkeley, CA
    I don't see how eliminating the standpipe reduces the risk of future flooding.

    Cheers, Wayne
     
  7. CM_George

    CM_George New Member

    Joined:
    Jul 17, 2020
    Location:
    Wisconsin
    The dishwasher I have is rated for a maximum of 10', which appears to be fairly industry standard. Moving it along the wall closer to the sink isn't really an option from the perspective of "traffic flow" within the kitchen, as well as being able to effectively have the dishwasher open and be able to use it.
    Maybe it's just me, but the idea of a standpipe drain that is open at the top just makes me nervous that it could overflow again. A "closed" system, where water only has two places it can go -- inside the dishwasher, and into the drain -- makes me more comfortable.
     
  8. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    You would have the capacity of the disposal chamber and the sink bowl(s) if unstoppered. Even if stoppered, the pressure could lift the stopper.

    Also, the standing water in the sink would alert you to a problem.
    One way to look at that is that they also probably have an elevation max. Since you are not lifting the drainage that much, the reduced head could compensate for some backpressure. In addition, you could use smooth pipe, rather than the corrugated they provide in their kits. You could in my non-professional opinion use a longer length of 5/8 ID smooth hose and not overtax the pump. Put an air gap on the right side of your sink, to minimize the distance that the DW is pumping. Harvey 093150 is a 50-ft coil that you cut to length.
    https://www.walmart.com/ip/William-H-Harvey-5-8-x50-Dishwasher-Hose-093150/168556803

    But if you feel that going beyond the 10 ft max printed in the manual of your dishwasher bothers you, you could buy a dishwasher that prints 12 ft.
     
    Last edited: Jul 17, 2020
  9. wwhitney

    wwhitney Active Member

    Joined:
    Mar 17, 2019
    Location:
    Berkeley, CA
  10. wwhitney

    wwhitney Active Member

    Joined:
    Mar 17, 2019
    Location:
    Berkeley, CA
    P.S. While it obviously makes sense to consider alternatives that have a reduced risk of flooding in the future, you can't judge the risk of a properly installed standpipe on the basis of your experience with the improperly installed standpipe. Just something to bear in mind as you consider whether it is worth doing more than just fixing the reverse slope on your standpipe trap arm.

    Cheers, Wayne
     
  11. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Besides the reverse slope, the standpipe trap arm may have been too long. An AAV, if permitted, could have addressed that.

    Clearly CM_George will sleep better without the standpipe concerns.
     
  12. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Joined:
    Sep 2, 2004
    Occupation:
    Retired Systems engineer for defense industry.
    Location:
    New England
    Mine probably goes about 10' and goes from a short hose to a barbed fitting onto pvc drain, then, into the sink cabinet where it transitions back to a hose and to the garbage disposal...been working fine for 20-years. I do not know if it would have worked well if it were longer.
     
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