Dishwash Drain Routing Around Corner

[cds0020]

I have a small U-shaped kitchen and had to put the dishwasher around the corner from the sink, which is on the small end of the U. I have a 48" long corner cabinet to go through before I can tie the drain line into the disposal. I am trying to figure out the best way to run the drain line. I see 3 options:

1) Run the drain line below the cabinets along the floor. Then come up through the bottom of the sink cabinet and make a high loop before hooking to disposal. There is room under the cabinets to do this and it would be the easiest and cleanest option if it would work. I'm worried about water sitting in the pipe as it runs along the floor, but wouldn't this happen in all cases?
2) Drill a hole HIGH in the corner cabinet beside the dishwasher and run the drain tight to the countertop. When I come into the sink cabinet, would I don't think I would need a high loop? Or would running tight along the countertop count as my high loop?
3) Drill hole in middle of cabinet and run drain line under middle cabinet. Then high loop in sink cabinet.

 

[Jadnashua]

The pump is fairly robust in most of those, so you can run it that length unless the manual specifically prohibits it. Water will tend to sit in the hose, but hopefully on that last rinse, it's no longer gross. My kitchen is about the same configuration. I had the opportunity to run pvc drain pipe beneath my cabinets (actually, I have mine mounted on about a 3" pedestal) with a barb fitting at each end where I attached the DW's drain hose at one end, and a short piece of hose to the disposer at the other. I wanted the pvc there verses a hose, since it would be nearly impossible or at least quite expensive to access later one where a hose might deteriorate.

Once the hose goes up to the bottom of the counter, that counts as your high loop. Note, in some places, a high loop doesn't cut it, and code requires an air gap fitting which is safer.

 

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[cds0020]

So you just ran PVC under the cabinets? Should I use CPVC since the water will be hot coming out? Could I eliminate some of the standing water if I sloped the PVC (or CPVC) drain from the dishwasher to the sink cabinet?

Also, are there any concerns with corners? Should I use (2) 45-degree fittings or is a 90 ok?

 

[Jadnashua]

PVC should be fine for the drain lines. A longsweep 90 might be better than a 'normal' one, but it probably doesn't really matter. YOu could use two 45-s. Mine has been in now for about 15-years with no issues. I'm not sure what a plumber would do...mine used a rubber hose initially, but I didn't like the fact that it would be buried, and essentially inaccessible long-term, so swapped it over to pvc. Consider that it is likely the drain water will go into pvc drain pipes once it gets to the sink...shouldn't really matter where it starts.