I have a garage disposal installed in my kitchen double sink. The pipe that comes out of the garbage disposal is horizontal to the main vertical pipe before it goes to the p trap. The t joint is baffled, and I am not a fan of this arrangement since it clogs quite often. (once in 6 months)

enter image description here

This causes a big problem for me since the dish waster is connected to the garbage disposal. How could I reconfigure this plumbing without the baffled t?

enter image description here

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    A few things don't look right to me, the disposal usually has an elbow coming off it so the water drains down a bit before going to the p-trap. I doubt you have enough slope on that connection. The baffle is important, so don't remove that, but I'd lower it if possible. And the AAV is way too low, it should be near the countertop so that a clog in the drain doesn't result in water backing up under your counter. – BMitch Aug 26 '13 at 13:27
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    You need to get more slope on that horizontal run. Anything coming out of your disposal should be ground up small enough so it doesn't catch there, but you need enough slope so the water drains quickly. – BMitch Aug 26 '13 at 13:37
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    Then that is your main issue. It means that everytime you have a "items" in your disposal they have to be pushed out by a massive amount of water. Luckily the kitchen sink has a lot of water at once when it is used. But any clog will get exponentially worse very quick with this set up. I would aim about 6 inches further down than you are right now. – DMoore Aug 26 '13 at 14:42
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    The AAV should be above the overflow level of the sink, which in most kitchen sink installs would be above the rim of the sink. – Tester101 Aug 26 '13 at 15:41
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    AAVs are not guaranteed to be water tight, which is why they are not approved in all locations. However, installing them above the overflow of the sink, insures that the sink will overflow before water starts spewing from the AAV (which may be under the sink or in the wall). – Tester101 Aug 26 '13 at 15:57

I would replace that hare-brained baffle T fitting with a 90° sweep tee fitting like this: enter image description here

I could not find the right flavor online, but I have also seen 1.5 inch white plastic with hand tightening connectors.

Even a 45° wye would be better:
enter image description here

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    From what I have found online about it the only purpose of the baffle is to keep water from backwashing into the other sink, I presume due to the pressure in which the water is ejected from the disposal. This seem to me like it would work much better – iamkrillin Aug 26 '13 at 18:08

When I am doing a disposal install (non professional but at least 10 for friends and family) I do a double 90 right away and slope drain down a bit from there.

After doing the double 90s you don't need that much slope but given you will potentially have food items I would maybe go 1/2" down overall on your straight into the T.

enter image description here

Also BMitch is right. The AAV I think by code is supposed to be on the surface but that is another question.

  • Your horizontal pipe there looks like its not slopped, are you saying that I should do something similar to that or maybe put in a 45 so I can slop it down? – iamkrillin Aug 26 '13 at 15:19
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    It doesn't have to be sloped much if you go down right after garbage disposal but yes it still needs to be sloped. You don't have to go 45 degrees. If you do that is great and will get things down faster but the main thing is not letting the food backup into the disposal area. – DMoore Aug 26 '13 at 15:20
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    Two 45s would be better than two 90s. A sanitary tee would also be better than a straight tee, but I'm not sure they make sanitary tee tailpieces. – Tester101 Aug 26 '13 at 15:52
  • @Tester101 - I agree but harder install and I am not sure it matters that much. – DMoore Aug 26 '13 at 16:16
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    @DMoore wasn't the initial question here how to avoid the straight tee? I guess you're saying here the elbow off the disposal helps something? Also any chance on updating that image with one showing a proper slope? I mean I'm sure the slope is there but...maybe call it out more? :) – rogerdpack Feb 1 '16 at 14:21

Here's my solution to the ridiculous baffle-T that provides only a 3/4 inch or less route to drain a 1.5 inch pipe full of waste. The PVC parts cost about $20 at the local hardware store and provides a fill 1.5 inch route for the chopped foodstuffs to exit. Why can't some plastic plumbing manufacturer figure this out and manufacture a simple 1 piece fitting like this?enter image description here


I know this is an old post but as a master plumber I would add a separate Santee for the disposal and arm over with its own trap.

  • images please? :) – rogerdpack Jan 21 '16 at 20:52

By far the most common configuration is the baffle tee (possibly code required). I wonder if perhaps the disposal is not doing its job well enough? I do like the suggestion of a wye combo or adding the immediate elbow so that more water pressure goes toward the baffle (and run it with water when you use the disposal).

Some other suggestions I ran into were to have the disposal elbow feed the "top" of the baffle tee (opposite to how its typically setup). Wonder if you could combine it "in the middle" with a double wye somehow.

This page http://nettally.com/palmk/GDplumbing.html suggests basically "use two separate p traps" however some codes might disallow this: http://ths.gardenweb.com/discussions/2508839

The other common thought seems to be "well at least the drainage problem is located near the top so you can fix is easily" (instead of getting pushed down the line and stuck there) though that doesn't seem ideal still...guess this is an unsolved problem. The other idea thrown around is to remove the disposal altogether (not greatly practical), then you can use a regular sanitary tee instead of a baffled. I have 4 units with disposals and never had anything caught at that particular location, FWIW...plunging might help/work as well. Or maybe breaking that baffle piece in half? :)

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