Why Is My Garbage Disposal Humming?

Updated: May 08, 2024

Discover reasons behind your humming, yet inactive garbage disposal with this troubleshooting guide.

Garbage disposals are one of the unsung heroes in the kitchen. Performing the thankless job of grinding up food scraps daily and sending them down the drain, they’re easy to take for granted. But if your garbage disposal stops working, it can disrupt the entire workflow of your kitchen.

If your garbage disposal is humming but not spinning, read on for expert troubleshooting tips and guidance from two licensed plumbers — Liam Hogan from Hogan Mechanical Incorporated and Armand Lamour, a master plumber from Smith Vocational and Agricultural High School.

Why Is My Garbage Disposal Humming, but Not Spinning?

Your garbage disposal may be humming, but not spinning, for various reasons, like:

The garbage disposal is jammed

Most likely, it’s stuck. “Usually it’s some sort of particle jammed in the impeller,” Hogan says, which prevents the blades from turning. Lamour agrees. “A portion of the inner disposal workings is likely jammed,” he says. This can happen if a piece of food, a plastic bag or utensil becomes wedged into the blade impeller and stops it from rotating. “You’ll still hear the hum as it powers on, but nothing will happen,” Hogan says.

The garbage disposal motor has failed

Besides an obstruction, the motor or other mechanical components may be failing or faulty. “It could be a bearing wearing out or the motor dying,” Hogan says. According to Lamour, a damaged or broken motor can stop spinning the impeller despite having power.

How to Fix a Garbage Disposal That’s Humming

Immediately turn off a garbage disposal that is humming but not spinning to prevent damaging the unit. You can try a few things before calling in a pro, depending on your skill and comfort level.

Safety Precautions

Before attempting to troubleshoot, always turn off the power to the garbage disposal. Especially when jammed, the blade could suddenly move when freed. Keep fingers away from the blade at all times.

Steps or methods to troubleshoot

If the unit is humming, there’s still power going to the disposal. “If that’s the case, you can rule out an electrical issue,” Hogan says. Here are some troubleshooting steps if your garbage disposal is humming, but not spinning.

  1. Turn off the power: Shut the power off at the disposal and the breaker and unplug the disposal if applicable.
  2. Visually inspect for obstructions: Use a flashlight to look into the disposal chamber. Use long-handled pliers or tongs to remove any food or utensils you find carefully. “Never put your hand or fingers in the opening of the disposal,” Lamour says. Run the water and test the disposal.
  3. Manually rotate the blades: If there are no obstructions, or the unit is still not working, insert an Allen key or disposal wrench (it comes with the unit) into the hex-shaped hole found at the bottom of the unit. Rotate the blade back and forth to help remove any remaining or unseen blockage. Turn the disposal flywheel only, do not try to move the blade directly with a tool or your fingers. Run the water and test the disposal.
  4. Smell and listen: If the disposal is still not working, it’s likely not a blockage, but a bad mechanical part. Failing motors can give off a burning smell. “You might also hear a grinding noise coming from the motor,” Hogan says, so listen for any unusual sounds when operating the disposal. These point to a failing disposal that requires replacement.

When to Call a Pro

“If you are unable to see and remove an object causing a blockage in the disposal, you can not get the disposal to spin manually using the Allen key in the bottom, or the disposal is leaking into the motor windings, it is time to call in a professional,” Lamour says.

However, replacing a garbage disposal can be a straightforward DIY project if you are comfortable with the required skills and have the necessary tools.


Do Garbage Disposals Go Bad?

“Anything mechanical can fail,” Hogan says, “However, you should expect 15 years of average use for a garbage disposal.”

How Do You Make a Garbage Disposal Last?

“Be mindful of what you put down them,” Hogan says. “In my home, we scrape plates into the garbage first, then rinse in the sink.” Lamour advises always to run the water when the disposal is turned on to keep the inside lubricated.

Regular cleaning can help extend the life of your disposal as well. “Grinding up lemon chunks every three weeks or so [keeps] the disposal smelling fresh and the acidity in the lemon juice will help free up stuck food particles,” Lamour says.

When Should You Replace Your Garbage Disposal?

If it goes bad and stops working, it’s definitely time to replace it. Hogan points out that if you’re doing a kitchen remodel, it’s a great time to put in a new disposal. “Tackle replacement then,” he says. Also, replacement makes sense if your disposal is starting to make loud noises, or if you’re looking for a quieter option.

About the Experts

  • Liam Hogan is the owner of Hogan Mechanical Incorporated a full-service residential and commercial plumbing company in Springfield, Massachusetts. He has a Journeymans Plumbing License.
  • Armand Lamour is a Plumbing Instructor at Smith Vocational and Agricultural High School in Northampton, Massachusetts. He holds a Master Plumbers license in Massachusetts, Connecticut and Rhode Island. Mr. Lamour has over twenty years experience in the field.