I have a in sink garbage disposal but rarely use it.

I just had to replace it because it burned out from a children's plastic spoon getting 'eaten' ... more than just seized there was smoke coming out of the unit.

So I have thought about just getting rid of it. But every house that I have lived in that has a dish washer also has had a in sink garbage disposal

I was wondering if they are needed \ recommended if you have dish washer?

4 Answers 4


Dishwashers usually have a built in food disposer, so having one is not required.

I also suggest just replacing the existing disposer instead of removing it altogether. Cheapest ones cost around $60 and since they usually feature a quick change mechanism, the whole process takes 15 minutes. But if you remove one, then you will have to reroute a drain pipe to accommodate for the missing disposer. Really not fun to do in the cramped space under the sink.


One advantage of using a dishwasher in conjunction with a garbage disposer is that the drain hose of the washer goes directly into the upper section of the disposer. This provides the needed isolation between the washer drain hose and the sink drain trap. This isolation prevents back flow from the drain back into the dish washer. Without a disposer present you would have to make a provision to mount an air gap assembly in the counter or the kitchen sink skirt.

Getting rid of the disposer means possibly having to drill a fairly good sized hole in your sink/counter for an air gap that you would have to purchase and then work out the proper drain hose attachment from the air gap unit over into the drain line. That is on top of the drain line rerouting that Vitaliy mentioned in his answer. At the end of the day I would think that a new disposer would be the simplest thing to do.

  • I think I've seen air gaps that snap into the hole for the spray head/detergent pump/whatever-accessory, so drilling might not be required.
    – keshlam
    Commented Oct 17, 2014 at 19:53
  • @keshlam - You are correct. The dishwasher Air Gap unit is very often mounted in the side sink hole that exists on many models of sink.
    – Michael Karas
    Commented Oct 18, 2014 at 8:14

Today's construction standards require a separate drain trap for dishwashers and are not drained into the garbage disposer as used to be common. Most likely your setup has a shared trap between the sink and disposer (if a double bowl sink) and the washer drains into the upper side input of the disposer. This is really not a bad set-up and was used successfully for many years. If this is true in your case, it would be easier and cheaper to simply replace the disposer rather than add new traps and reconfigure the drain system under the sink.


Seperate drain for the dishwasher is a good idea.. it reduces the amount of water going through the disposal and should increase the life of it. Just be sure to route the dishwasher drain hose up and then down to prevent backflow into it from the sink. Not that difficult. Or you may need to put a seperate trap if your codes require it.

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