My sink set up gets blocked all the time when putting food through the garbage disposal. I took it apart and noticed the "Tee" had a very small hole for garbage disposal waste to pass through causing the problem so I removed this thin piece of plastic and now water backs up into the second sink when I flip on the garbage disposal. Water even shoots up through the garbage disposal side of the sink.

What good is a garbage disposal if you can't put vegetables, egg shells, and other food scraps through it.

Attached is a picture of my current set up and I don't think its right.

Kitchen Sink Plumbing Setup Kitchen Sink Plumbing Setup

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    The Air admittance valve, what you call a baffle, is not installed high enough. This could be contributing to your sink backing up, as water could be preventing it from opening. It should be up as high as it can be in the space. The thin piece of plastic you removed was there to stop water that is being violently eject by the disposal from shooting up and out of the other sink. Also it sounds like your disposal is not macerating the food waste efficiently, ( small enough )
    – Alaska Man
    Jan 28, 2019 at 17:56
  • If I put the "Tee" with the baffle higher then I would need to have the garbage disposal higher? Based on your answer I will have to replace the "Tee" that cut the baffle out of with a new one. Maybe a better garbage disposal would be the answer? Jan 28, 2019 at 21:50

1 Answer 1


Your set up is missing a critical piece. The disposer elbow (discharge tube). Here is a very good article with plumbing schematics and instructions to correct your issues.

Disposer Schematic

Note: I can't tell from your picture, but is there a sanitary street-t where your waste enters that sewer line? A sanitary tee should be used when connecting a horizontal pipe, such as a waste arm to a vertical riser. This will help move that waste along a little better.

Sanitary Street Tee

  • I dont think I can use that set up, as much as I would like to, because of the main vented sewer line coming out of the floor directly behind the trap. Jan 28, 2019 at 15:07
  • If I use that fitting I will have to hard plumb the straight line from the disposal and the tail line from the sink. Jan 28, 2019 at 16:34
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    I was actually referring to placing it at the rear, where the piping enters the floor. Jan 28, 2019 at 16:54
  • Thanks a lot for your link, which is exactly what I was going to ask about. I see so many "experts" showing the first method, but the one with the wye is seldom shown. I will try this method to see if it helps slow drainage for our sink. Oct 4, 2021 at 1:04

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