I have read up on existing questions on this issue, and I understand it is a fairly common issue.

Unlike some other people, my kitchen sink hasn't been clogged, and the garbage disposal works fine. But there is always water at the bottom of my Frigidaire dishwasher (model FFBD2411NS), as high up as going up 1 inch over the bottom.

I called in a maintenance technician from the dishwasher warranty contract company, and he checks the dishwasher's drain hose and tells me the dishwasher works alright, and it's my kitchen sewage that's clogged. I remember seeing him unplug the dishwasher hose and water flow out of it from the dishwasher, which according to him shows that the dishwasher should drain properly.

Despite I don't see any clog, I tried some clog remover liquid. I also called in a plumber and had the kitchen drainage checked, but was told my kitchen sink wasn't clogged.

Now water still backs up, giving out a strong repellent odor, and we can't use the dishwasher as a dishwasher because of this. We have been using it as dish racks.

As @manassehkatz suggested, I am putting up a picture showing the drain hose path. There doesn't seem to be a high loop. Should I create one by elevating the hose?

  • Did the plumber check the vent for the kitchen drain or vents in general?
    – JPhi1618
    Feb 20, 2018 at 20:15
  • @JPhi1618 I am not sure. I wasn't watching the whole time. Should I have it checked?
    – Eddie Kal
    Feb 20, 2018 at 20:17
  • 1
    How long has it been happening? Is your kitchen disposal unit new? If the dishwasher is plumbed to the disposal, ensure that the plastic knockout plug has been removed. I would assume (since both a plumber and the dishwasher repairman have been around) that this is not the cause of the problem, but you can't be sure until you check for yourself.
    – CactusCake
    Feb 20, 2018 at 20:19
  • 1
    Vents are often overlooked, and they can cause backups when high-output fixtures like dishwashers or washing machines drain. A typical stream from the faucet might not show symptoms. And dishwasher water typically doesn't stink, so it sounds like the rush of water from the dishwasher is bringing up black water from further down the drain.
    – JPhi1618
    Feb 20, 2018 at 20:19
  • 1
    @EricMlyn, you won't be able to "see" anything, and like I said the symptoms are not always obvious. Snaking the vents from the roof is a common method of clearing a vent, but without knowing your skill level and roof design, I can't recommend you try this on your own.
    – JPhi1618
    Feb 20, 2018 at 20:28

2 Answers 2


A dishwasher drain requires an air gap in order to function properly. This prevents water that has drained out - and also water coming from the sink/disposal - from coming back into the dishwasher. There are two ways to install an air gap. The traditional way is the drain hose goes up to an air gap device installed in the corner of the sink and another hose goes down to the disposal. Many dishwashers include a long hose and are designed so that the hose can be attached to the underside of the counter as a "high loop". This effectively provides an air gap as the water is pumped out and goes over the top of the loop but can't come backwards to the dishwasher unless the drain/disposal was blocked and water filled up in the sink to the same level as the top of the loop. No special equipment is needed - just a wire or clip to hold the middle of the hose up high. More details and picture at Draining problems in dishwasher. Is this drain setup ok?

The installation instructions for your particular dishwasher FFBD2411NS Installation Manual show the correct installation of the drain hose, but unfortunately don't explain WHY it should be installed that way, so I can see how it could easily be innocently installed incorrectly.

  • +1 Beautiful answer! Thank you. What should I do with the long hose? Should I loop it or leave it at that?
    – Eddie Kal
    May 8, 2018 at 3:51
  • @EddieKal The hose is long because some installations need it to feed through a cabinet to get from the dishwasher to the drain. It should feed as straight up as reasonably possible to a point where it is attached underneath the counter, as high as possible. As far as I can tell, if it loops a little on the way down to the disposal that's not a big deal, though ideally it would not have any sections below the disposal inlet so that it won't hold any water between uses of the dishwasher. May 8, 2018 at 3:59

Get a 25' snake that attaches to your drill from Walmart. They are about $20 or so. Clean out your J trap and snake where the pipe goes into your wall. Get on the roof and snake the vent. If that doesn't work then get a new dishwasher or see if the sewer company will come jet out the waste pipe at the curb and that might help.

  • 1
    Snaking should only be done when it is determined to be a real problem. If you snake PCB too aggressively, you can permanently damage the hose, and that becomes a very $$$$ bill.
    – Nelson
    Feb 2, 2021 at 4:35

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