Plumbing Advice
Why Is My Garbage Disposal Humming but Not Working?
By Kenneth Parks ·
A garbage disposal humming but not spinning almost always means the motor is getting power but the grinding plate is stuck, usually from something wedged inside or from the unit sitting unused. Most of the time it can be freed up safely, but if it keeps jamming or trips its reset button over and over, the motor may be on its way out.
I have been doing plumbing for more than 35 years, and I still get this call every week. Here is what is going on under your sink and how I think about it.
What the Hum Is Telling You
Inside the disposal, an electric motor turns a round plate with two small swiveling lugs. Those lugs fling food against a grinding ring. When you flip the switch and hear a hum, the motor is trying to turn. Something is just keeping it from moving.
Common reasons include:
- A hard object caught between the plate and the ring, like a fruit pit, bone, bottle cap or a small spoon.
- Fibrous or starchy food packed in tight, such as celery, onion skins, rice or pasta.
- Rust and mineral scale holding the plate after weeks of not being used.
- A worn motor or bearing that no longer has the strength to start.
A Safe Way to Unjam a Garbage Disposal Humming in Place
Before anything else, turn the disposal switch off and unplug the unit or shut off its breaker. Never put your hand inside, even with the power off.
- Look on the bottom of the disposal for a small hex-shaped hole in the center. Many units have one.
- Insert the matching hex wrench and work it back and forth until it turns freely all the way around.
- Use tongs or pliers, not fingers, to pull out anything you can see from the top.
- Wait a few minutes for the motor to cool, then press the red reset button on the bottom.
- Restore power, run cold water, and try the switch.
If it spins, you are probably fine. If it hums again right away, stop. Running a stuck motor makes it hotter and can burn it out.
A Real Story from a Glendale Kitchen
A while back I met a couple in Glendale who had just come home after spending the summer up north. Their disposal hummed and would not budge. They had already tried the reset button a dozen times.
When I got under the sink, the plate was locked with rust and scale from sitting for months with a little water in it. I freed it with the hex wrench, cleared some old debris, and it ran, but the bearing was rough and noisy. I explained that it might last a while or might not, and let them decide. They chose to replace it while I was there. That is how I like it: you get the facts, then you make the call.
If you leave for the season, our snowbird plumbing checklist covers how to keep things like this from happening.
When It Is Time to Call a Plumber
I will be honest. Plenty of jams are a five-minute fix you can do yourself. But some signs mean it is more than a jam:
- The reset button trips again and again.
- You see water leaking from the bottom of the unit. That usually means the inside seals have failed, and the unit needs replacing.
- The sink drains slowly even when the disposal runs. The clog may be past the disposal, and our drain cleaning service can find it with a camera instead of guessing.
- You smell something burning or the switch feels hot.
If the disposal is old and leaking, a replacement is usually the smarter move. We also handle the faucets and fixtures around it if those need attention.
Help With a Garbage Disposal Humming in Phoenix
If your garbage disposal humming has you stuck, text a photo of the unit and the label to 602-596-3013 for a free rough estimate, or call 602-428-2585. We handle garbage disposal repair and replacement across Phoenix, Glendale, Peoria, Tempe, Scottsdale and Chandler. Every job comes with a 1-year parts and labor warranty, and you will know the price before we start. That is how we work at Do It Right Plumbing.
Help With a Garbage Disposal Humming in Phoenix