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Table of Contents

Remove the Knock-Out Plug on a New Garbage Disposal

Check the Sink Air Gap if Installed

Advanced Troubleshooting to Find Out Why Your Dishwasher Won’t Drain

Check for Error Codes

Preventing Drain Problems in Your Dishwasher

Schedule your dishwasher repair now!

Call (213) 596-2538
  1. Resource Center
  2. Repair

Why Your Dishwasher Won’t Drain

5 min readUpdated Mar. 08, 2024Kimberly HillegassDishwasher
Homeowner seeing his dishwasher not draining

When your dishwasher fails to drain after a cycle, it's often a cause for concern. Before diving into complex troubleshooting, start by checking the garbage disposal for any clogs, a common culprit. If the issue persists, this guide offers expert tips to diagnose and address the problem, ensuring your dishwasher operates smoothly once again.


  • Dishwasher drainage issues can often be traced back to problems with the garbage disposal or air gap.
  • If basic checks don't resolve the drainage problem, consider advanced troubleshooting steps outlined in the owner’s manual or seek professional assistance.
  • Regular professional maintenance by Sears Home Services can help prevent dishwasher drainage problems.

When you open the dishwasher door at the end of the cycle and still see water in the tub, the first thing you should check is the garbage disposal in your kitchen sink. Most dishwashers connect to the garbage disposal and if the disposal is full, the water won’t drain from the dishwasher.

You can activate the disposal to get rid of waste and clear the drain path for the dishwasher then start a new dishwasher cycle to see if that fixed the problem.

If not, you can continue on with expert troubleshooting tips described in your owner’s manual and outlined below.

Remove the Knock-Out Plug on a New Garbage Disposal

A frequent cause of a dishwasher not draining is failing to remove the dishwasher drain knock-out plug when installing a new garbage disposal. Check this issue if you just replace the garbage disposal for your kitchen sink.

If the knock-out plug is still in place, follow these steps to remove it:

  1. Unplug the garbage disposal to disconnect electrical power.
  2. Place a bucket or container under the dishwasher drain hose connected to the garbage disposal.
  3. Disconnect the dishwasher drain hose and place the end of the hose in the bucket or container. Water will likely spill out of the dishwasher drain hose.
  4. Push a slot screwdriver into the dishwasher drain hose connection on the garbage disposal and carefully tap it to remove the knock-out plug. The piece of metal that is the knock-out plug will fall into the garbage disposal food chamber.
  5. Retrieve the knock-out plug from the chamber using pliers (or your fingers).
  6. Reconnect the dishwasher drain hose and plug the garbage disposal back in to restore power.

If you had a professional install the garbage disposal, you may be able to have the installer perform these steps for you.

Check the Sink Air Gap if Installed

Many kitchen sinks have an air gap installed that prevents drain water from backing up into the dishwasher. This air gap can get clogged with deposits or debris and prevent the dishwasher from draining.

Check the air gap for a clog and clear it if necessary so the dishwasher will drain.

Advanced Troubleshooting to Find Out Why Your Dishwasher Won’t Drain

If you haven’t found and fixed the cause of the dishwasher draining problem using the above tips and guidance from your owner’s manual, then you’ll likely need to schedule service by a technician or use the advanced troubleshooting tips shown in this video to fix the dishwasher:

You may find a clog in the dishwasher drain hose or figure out that you have a bad drain pump. A control problem or wiring failure can also prevent the dishwasher from draining.

Check for Error Codes

Dishwashers with electronic controls often display error codes when the circuit board detects a component failure inside the dishwasher. A digital code or a pattern of blinking lights will appear on the control panel to signal an error code. The code may help you determine what’s preventing the dishwasher from draining.

If you see an error code on the control panel, look up technical information about the code on our Dishwasher Error Code Charts or refer to the owner’s manual for your model to find out what the error code means.

Follow the troubleshooting tips in the owner’s manual and/or the Dishwasher Error Code Chart to find and fix the cause of the drain problem. If you’re unable to fix the problem yourself, schedule service and we’ll send a Sears Home Services Technician to your home to diagnose and repair the problem.

Preventing Drain Problems in Your Dishwasher

Annual professional maintenance by Sears Home Services will help prevent drain problems in your dishwasher. While completing comprehensive checks and maintenance of the dishwasher, the technician will complete these tasks that will help make sure that the dishwasher drains properly:

  • Check the drain pump for proper operation and advise you of any problems.
  • Clean removable filters that can inhibit water flow through the drain pump.
  • Test the operation of the electronic control board or timer for proper drain pump activation.

These preventative maintenance steps will help keep your dishwasher in top shape and draining properly all year long. Scheduling annual professional maintenance will also help your dishwasher last longer.

To help keep all of your home appliances in top shape, schedule the Kitchen & Laundry Appliance Cleaning and Maintenance Bundle. A technician will visit your home to check, clean and maintain all of your appliances in one convenient visit.

Trust Sears Home Services to help you keep your home appliances in top shape and help you manage your entire home so you can relax and enjoy life comfortably.

Schedule your dishwasher repair now!

With extensive experience, our technicians are skilled in repairing dishwashers of all makes and models, ensuring sparkling clean dishes with every cycle.

Call (213) 596-2538 or schedule online now.

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