Draining problems in dishwasher. Is this drain setup ok?

Question

I have issues with dirty water in filter area and dishes not coming clean. This is a new dishwasher. Old one had similar issues so I think it is the drain and not dishwasher. Is the drain setup ok? Would it be better going to disposal? There is no possibility of adding an air gap.

Update: The upright pipe is what I think is an attempt at a loop..air gap thing. The plastic drain hose from the dishwasher comes out of the dishwasher..across the bottom of the cabinet. Up the side of that white pipe where it becomes clamped to a copper pipe. That empties into the white pipe which goes back down to the bottom of the cabinet and out its own drain. Thanks!

Answer 1

Put the dishwasher drain line into the disposal. But that is NOT your air gap. There is a difference between an air gap and a trap. The output of the disposal has a trap, which is important. But you also need to have an air gap. A trap prevents sewer gas from escaping through the drain. An air gap prevents sewer water from coming into the dishwasher if the drain pipe is clogged.

However, an air gap does not need to be the old style of funny looking metal/plastic thing on the corner of the sink. Instead, you can use a flexible hose from the dishwasher that loops up above the height of the sink drain, as far as possible to the underside of the counter and then loops down and into the disposal. This does not require anything visible above the counter or any cutting holes into the sink or counter.

Assuming the corrugated plastic tube is your dishwasher drain line, move the end to the disposal and attached the middle of it as high up under the counter as you can and you're all set.

Answer 2

Put the dishwasher drain line into the disposer. The disposer internal cavity becomes your air gap.

There is a slug inside the disposer dishwasher connection that needs to be removed.

Answer 3

It's possible that the drain line is just too long (developed length). I'd guess that somewhere in the installation instructions it says to only use the supplied drain hose, and not to extend it. This is because the length of the supplied drain hose was specifically chosen, based on the size of the discharge pump.

You don't show what's at the top of the copper pipe, but I'm guessing it's some type of U shaped pipe. So while it may seem like you've only extended the drain line a foot, or so. The bend at the end of the tube, could actually be like adding an additional foot or so. With this setup, you may have actually added two feet to the developed length of the drain. That may not seem like much, but it could be enough to cause poor draining.

Draining in to the disposer is definitely and option, and seems as though you should have enough drain hose length to do it. Just make sure you secure the drain hose in to the high loop configuration, that's described in other answers. Don't forget to make any modifications to the disposer, to allow it to accept the drain. And don't forget to cap the abandoned standpipe. Left unused, the trap will dry out, and allow sewer gas to enter the living space.