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Does A Broken Garbage Disposal Affect Dishwasher

In most houses, dishwashers are connected to garbage disposals. So, if your garbage disposal breaks down, will it affect the working of your dishwasher?

A broken garbage disposal affects the working of the dishwasher if it prevents the dishwasher from draining properly. As the dishwasher’s outlet is connected to the garbage disposal, any clogs in the disposal will cause water to back up into the dishwasher and the sink.

Does a broken garbage disposal affect a dishwasher

A dishwasher works independently of the garbage disposal. So not all garbage disposal problems affect the working of the dishwasher; only a few do. Let’s see what the various garbage disposal problems are and how they affect a dishwasher’s work.

How does a broken garbage disposal affect a dishwasher

Let me first define what people mean by broken garbage disposal. It simply means a garbage disposal that is not working.

When there are a dishwasher and a garbage disposal under the countertop, the drain pipe from the former is connected to an inlet on the latter. So the wastewater from the dishwasher drains through the garbage disposal. Any problems inside the garbage disposal that blocks this draining affect the working of the dishwasher.

So, a dishwasher’s working is affected only if the problem with garbage disposal blocks its water from draining.

A garbage disposal can be broken due to various reasons. Let’s see how different types of broken garbage disposals affect the working of a dishwasher. Here are some scenarios;

A jammed garbage disposal

A garbage disposal is jammed when its blades are not able to rotate freely. This can be due to rust or due to the presence of foreign objects like steel utensils. Such a garbage disposal does not necessarily prevent water from draining. Its blades are not moving, but there is still plenty of space for the water to drain.

A jammed garbage disposal doesn’t prevent the water from the dishwasher from draining, so it doesn’t affect the dishwasher’s working.

A garbage disposal that doesn’t run

Your garbage disposal may fail to run due to electrical problems, a burned motor, and various other reasons. But none of these reasons prevent the dishwasher water from draining. So it is safe to say that a broken garbage disposal does not always affect a dishwasher.

A garbage disposal that is not draining

A garbage disposal fails to drain when it or the drain pipes are clogged. Such a garbage disposal affects a dishwasher’s working because the clogs prevent the dishwasher water from draining. Consequently, the dishwasher’s water may back up into the sink or back into the dishwasher. Modern dishwashers have a valve that prevents backflow, but failing to drain properly affects their working nonetheless.

If your garbage disposal is clogged, do not run the dishwasher. A sink with standing water or one that is draining but only slowly is an indicator of clogs in your garbage disposal.

A garbage disposal with leaks

A garbage disposal can leak from the top, sides, or bottom. None of these problems affect the working of a dishwasher. A few good leaks may even help the dishwasher to drain faster 😀

Draining a dishwasher when the garbage disposal is broken

A garbage disposal affects the working of the dishwasher only when the former is clogged. There are two ways to drain the dishwasher in such a scenario. Here are they;

  • Unclog the garbage disposal
  • Plumb a separate drain for the dishwasher

Unclog the garbage disposal

Clogs prevent a garbage disposal from draining. The clog can be anywhere; inside the garbage disposal or in the drain pipes. The first step to unclogging is correctly identifying where the clogs are. Unfortunately, the only way to do this is by disconnecting the drain pipes one by one, and cleaning and snaking them. This is a long and tedious process.

Here is a short video on unclogging a garbage disposal. Also, feel free to check my detailed unclogging guide.

Unclogging a garbage disposal

Plumb a separate drain for the dishwasher

Even though most licensed plumbers drain the dishwasher into the garbage disposal, it is better to plumb a separate drain for the dishwasher. This isn’t easy to do if your’s is a single basin sink. However, if you have a double basin sink, you can bypass the garbage disposal and plumb the dishwasher drain to the main drain pipe.

Should you connect a dishwasher to a garbage disposal?

All garbage disposals come with a dishwasher inlet. Many plumbers also recommend connecting the dishwasher to the garbage disposal. But are you required to do so by plumbing code?

It is not required to connect a dishwasher to a garbage disposal. In fact, doing so is a violation of the plumbing code in states like Illinois. The plumbing code of Illinois mandates that a dishwasher should discharge separately into a drain or tailpipe and not into a food wastes disposal.

The dishwasher outlet is connected to a garbage disposal out of practicality. It is difficult to add a separate drain connection for the garbage disposal, especially if there is only one drain pipe coming from the sink. If yours is a double sink, you can use a branched tailpiece for the second sink to connect the dishwasher outlet to.

dishwasher plumbing for a dual sink

You don’t need to use a garbage disposal to grind the food waste from a dishwasher. The food wastes coming from a dishwasher are too small to be ground by the garbage disposal. These food wastes can easily pass through the small holes of the garbage disposal’s grinding ring and into the drain pipes.

Benefits of connecting a dishwasher to a garbage disposal

Even though it is not mandatory to connect a dishwasher outlet to the garbage disposal, doing so has some benefits.

  1. Convenience: It is straightforward to connect the dishwasher to the garbage disposal than connect it directly to the drain pipes. Like I mentioned before, if there is only one drain pipe from your sink, there is no room to connect the dishwasher outlet other than the garbage disposal.
  2. Prevents flooding of the dishwasher: You can install a separate drain pipe for the dishwasher. However, if this drain gets clogged, the water will back up into the dishwasher. But if the dishwasher is drained via a garbage disposal, any backup water will go into the sink rather than back into the dishwasher.
  3. Reduce installation costs: Plumbing separate drains for your garbage disposal and dishwasher takes time and costs money. You can save a lot in labor charges and parts by hooking up your dishwasher with the garbage disposal.


Some but not all problems with the garbage disposal affect the dishwasher. The dishwasher is affected only if the garbage disposal is clogged and prevents the dishwasher from draining. Other problems like rust, leaks, and broken parts do not affect a dishwasher.

My name is Thomas Anderson, and I have worked briefly as a plumber. Even though I am currently working on a different career path I still help out my friends and family with their plumbing issues. This is a hobby blog where I share my knowledge with the audience through random articles. Through this blog, I hope to address some common questions about garbage disposals.