Sink, disposal, dishwasher plumbing

We keep getting a really bad oder from the dishwasher. It seems like the issue is the sink water backing up into the dishwasher or something. Anyway I think it may be an issue with the whole setup not being plumbed right. I have attached a picture of the setup with hopes someone will chime in and say it's wrong and tell me the proper way it should be. Thanks

Not a very good setup. With the p-trap laying on its side I think the water is not sealing off the gases. I found a
picture on how it should be hooked up.

TomFOhio said:

Not a very good setup. With the p-trap laying on its side I think the water is not sealing off the gases. I found a
picture on how it should be hooked up.View attachment 18272

Click to expand...

That pitcher is good other then the DW hose should loop up as high as possible

I'm not too fond of the "handyman" repairs that were made before I met my wife. After looking at those pictures I dunno why they would route the plumbing of the disposal forward instead of down. I can see how the p trap would not seal off gasses as there is always an air gap with it's current configuration. I will go home tonight and see about making the adjustment to the trap. First thing I did with the new dishwasher was make sure the hose was up high just like it says in the instructions, previous setup was the hose just coiled up in the cabinet. I had been telling my wife for quite some time that the way the plumbing was under the sink just didn't look right but then again I have very limited knowledge of plumbing so I finally took to the forums to get some info, I appreciate it!

Yes, good point John they should of got it a lot higher than it is. Just remember v1ru5879 that you need to get the hose from
the dishwasher as high as possible under your sink to make a trap.

TomFOhio said:

Yes, good point. They should of got it a lot higher than it is. Just remember v1ru5879 that you need to get the hose from
the dishwasher as high as possible under your sink to make a trap.

Click to expand...

Yeah I have it routed up to the countertop before it comes down to the disposal

Only thing I can think would be an issue is the exit pipe is almost level with the exit pipe of the disposal

Uhhm, isn’t there still a code requirement for an air gap in the drain line from the dishwasher?

Re the original photo: the ninety on the garbage grinder should have been mounted down, and should then connect directly to the p-trap, with out the convoluted mess. It will look a lot like the second picture by johnjh2o.

Oh my goodness. It's not even entirely clear that the drain exit is lower than the disposal exit. I think it probably is - since apparently water does drain - but just barely.

The only way this disposal/sink/dishwasher is going to drain properly
is to cut the wall, lower the drain coming out of the wall and plumb the sink/disposal correctly

OK... That corrugated pipe has to go. Granted, the pipes are almost level, but the wall drain IS lower than the disposal outlet. You may have to do some cutting, but :
1) remove black pipe from disposal (don't lose foam washer)
2) Get a 4" "tailpiece" and loosely connect to disposal where you removed black pipe.
3) get "Slip Joint 1-1/2" Waste Arm" to go into top of p-trap. The tailpiece and waste arm will have to be cut (trial and error) to give you the connection you need.
After all fittings look good, tighten all connections. Don't forget the bolts on the disposal.

The loop on the dishwasher drain should be as close to the top of the sink as possible to prevent water being siphoned back to DW.

I believe the question is just how much lower is the wall pipe? And is it enough to add a bend at the trap inlet?

Garbage disposals typically want the trap weir to be a minimum distance below the unit but I suspect if you can fit a bend in there, that should satisfy it.

House Doc said:

OK... That corrugated pipe has to go. Granted, the pipes are almost level, but the wall drain IS lower than the disposal outlet. You may have to do some cutting, but :
1) remove black pipe from disposal (don't lose foam washer)
2) Get a 4" "tailpiece" and loosely connect to disposal where you removed black pipe.
3) get "Slip Joint 1-1/2" Waste Arm" to go into top of p-trap. The tailpiece and waste arm will have to be cut (trial and error) to give you the connection you need.
After all fittings look good, tighten all connections. Don't forget the bolts on the disposal.

The loop on the dishwasher drain should be as close to the top of the sink as possible to prevent water being siphoned back to DW.
View attachment 18282

Click to expand...

Thank you so much! I was actually getting ready to hack into the wall as another oater suggested. I will be at my Lowe's first thing tomorrow morning

I'm not a plumber, but I have been a handyman for over 40 years and many times I have to get creative to solve my customers problems. I don't have the overhead most plumbers have, so if I can solve a problem for $75 dollars instead of $350 I will save my customers that difference. Sometimes it just takes looking at things a little differently.

Another handyman here, and let me be the first to say whoever did that "repair" was not a handyman IMHO.

Putting any other code issues aside ( I would suspect the drop from disposal to drain is too small) the use of flex pipe is sketchy at best...using it in a near vertical installation on a disposal is a catastrophe. Think about the gray water full of food particles laying in the folds of the flex and its no wonder it stinks.

Got around to doing what was suggested. I am always paranoid about leaks so I have the bucket under to ensure no dripping. I had to rotate the disposal to make it line up with the p trap. I guess I could have cut the exit pipe down but I figured the less invasive the better

If you ever get adventurous. It looks like you have enough room so that you can cut the "exit pipe" from the disposal and the pipe connecting to the wall and rotate the disposal so that its at 90° from the door and recover some more under counter space.