How to Remove a Garbage Disposal Knockout Plug: A Guide


There are some real benefits to pairing a dishwasher with a garbage disposal, like fewer sink clogs and no more pre-rinsing dishes. But what if your dishwasher fails to drain after attaching it to your disposal unit? Don’t panic, as this is a common issue that can easily be resolved by removing the garbage disposal knockout plug. This small plug may seem insignificant, but it plays a crucial role in allowing water to flow freely from your dishwasher.

In this guide, we will walk you through the steps on how to remove a garbage disposal knockout plug and get your dishwasher draining without any issues.

What Is a Garbage Disposal Knockout Plug?

Before we dive into the removal process, let’s first understand what a garbage disposal knockout plug is. See, this small piece is designed to block the dishwasher connection on your garbage disposal. It’s mainly used when you only have a garbage disposal installed and no dishwasher.

However, if you have both appliances and forgot to remove the plug, it can cause serious drainage problems. The water from your dishwasher will be unable to flow through the blocked pipe, causing it to back up and potentially flood your kitchen. So, it’s essential to remove this plug before connecting your dishwasher to the garbage disposal (or vice versa).

Step-by-Step Guide to Remove a Garbage Disposal Knockout Plug

Removing the knockout plug is a simple process that anyone can do with the right tools and instructions.  Here’s how to do it:

Step 1: Gather Your Tools

The first thing you’ll need to do is gather the right tools for the job. To remove the knockout plug, you will need a:

  • Hammer
  • Flat-head screwdriver
  • Needle-nose pliers
  • Towel or cloth

Step 2: Turn Off the Power

Before you begin, make sure to turn off the power to your garbage disposal. You’ll either need to unplug the unit or turn off the circuit breaker that controls it.

Now, this may seem like common sense, but it’s a crucial safety precaution that cannot be overlooked. You don’t want any accidents while attempting to remove the knockout plug.

Step 3: Locate the Knockout Plug

Next, locate the knockout plug on your garbage disposal unit. Look for the drainage port near the top of the unit, and disconnect the dishwasher’s drainage tube if it’s already attached. The knockout plug should be behind this tube mount inside your disposal unit.

To see if it’s there, use your screwdriver to gently push into the drainage hole. If there’s nothing blocking it, then your knockout plug has already been removed, and there’s something else causing your problem. But if you hit something solid, you’ve found it!

Step 4: Knock It Out

Now that you’ve located the plug, you’re going to do exactly what the name implies: knock it out. You can do this by gently tapping the back of the screwdriver against it with the hammer. And don’t just stay in one place – move the screwdriver around to knock out the entire plug evenly. Just be careful not to hit too hard, as you don’t want to damage the inside of your disposal unit.

Eventually, the knockout plug should come out and fall into your garbage disposal. You can now use your needle-nose pliers to reach down through the sink opening to retrieve it.

Step 5: Clean Up and Attach

Before testing out your newly freed drainage hole, you may want to take the opportunity to clean up any debris or plastic shavings that may have fallen into or around the garbage disposal during the knocking out process.

Then, reattach the dishwasher’s drainage tube if it was disconnected earlier, or attach it for the first time as part of the installation process. Finally, turn on your garbage disposal and run some water to see if the problem is solved.

What If It’s Not the Knockout Plug?

While the knockout plug is likely to blame for your dishwasher not draining, there are a few other possible culprits. If knocking out the plug didn’t solve the problem, then you may want to check for:

  • Clogs in the dishwasher hose or pump
  • Faulty drain pump
  • Dirty filter and trap
  • Blockage in the garbage disposal

If none of these seem to be the issue, it may be best to call a professional plumber for further assistance. 

However, if you did successfully remove the knockout plug and your dishwasher is now draining properly, then congratulations! You’ve just saved yourself from a potentially costly repair or replacement.

How to Make the Most of Your Dishwasher and Garbage Disposal Combo

Now that you know how to handle a knockout plug, here are some additional tips to help ensure your dishwasher and garbage disposal continue working smoothly together:

  • Run cold water while using the garbage disposal to prevent food particles from sticking to the inside of the unit.
  • Learn what you can and cannot put in a garbage disposal. For example, you should avoid putting large chunks of food or hard items (like bones or fruit pits) into the garbage disposal, as they can cause clogs or damage.
  • Regularly clean and maintain both your dishwasher and garbage disposal to prevent buildup and odors.

With these tips in mind, you should be able to enjoy a hassle-free experience with your dishwasher and garbage disposal combo.

The Bottom Line

Removing a garbage disposal knockout plug is a simple and essential step when attaching your garbage disposal to your dishwasher (or, again, vice versa). But by following the steps outlined in this article, you can save yourself from the frustration of a non-draining dishwasher and potentially costly repairs. Plus by properly maintaining your dishwasher and garbage disposal, you can continue to enjoy the convenience they provide for years to come.

So next time you have a new dishwasher or garbage disposal to install, don’t forget about that little plug!  You won’t need to worry about any potential kitchen disasters – just smooth and efficient cleaning. And remember, if in doubt, it’s always best to consult a professional for assistance. Good luck!

Still looking for a quality garbage disposal to use with your dishwasher? Check out the highly rated InSinkErator Badger 5 here.

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