What Is Happening
When you flip the switch and hear a hum, the motor is trying to spin but physically cannot. Something hard has wedged itself between the rotating impeller plate and the fixed shredder ring. Common culprits include small bones, fruit pits, broken glass, a piece of plastic, or a utensil that fell in.
If you leave the disposal humming for more than about 15 seconds, the motor will overheat and the built-in thermal overload will trip, shutting the unit off to protect itself. This is normal and by design -- you did not break anything.
If you flip the switch and hear nothing at all -- no hum, no sound -- that is a different problem. The overload may have already tripped, or the unit is not getting power. We will cover the reset for that too.
How to Fix It
No Allen Key? Here Is an Alternative
If you cannot find an Allen key, you can try to free the jam from above using a wooden broom handle or a thick wooden spoon handle. With the power off, insert the handle into the disposal from the top and press it against one of the impeller blades. Push it in the direction of rotation (or either direction -- you are just trying to break the jam loose). Apply firm pressure. Once the impeller moves freely, remove the handle and follow the remaining steps above.
Do not use a metal tool from above. Metal can damage the impeller or shredder ring.
What If It Still Does Not Work?
If you have cleared the jam and pressed the reset button but the disposal still does not turn on:
Check the reset button again. Sometimes it needs a firm push. If it pops back out immediately after you press it, the motor may still be too hot. Wait 10 minutes and try again.
Check the power. Make sure the wall switch is on and the circuit breaker has not tripped. If the disposal is plugged into an outlet under the sink, make sure the outlet is working by plugging in something else.
The motor may be burned out. If the disposal jammed and hummed for an extended period before the overload tripped, the motor windings can overheat beyond recovery. This is more common with older units. A burned-out motor means replacement rather than repair -- garbage disposal motors are not economically rebuildable. A new disposal costs $80 to $250 for the unit, plus $100 to $200 for installation if you do not want to do it yourself.
Preventing Future Jams
Most jams are preventable with a few habits:
- Always run cold water before, during, and for 10 seconds after using the disposal. Cold water solidifies grease and fat so the disposal can chop them up. Hot water melts grease and lets it coat the inside of the drain, where it hardens later.
- Feed waste in gradually. Do not shove a large amount of food in at once. Let the disposal process a little at a time.
- Avoid putting these items in: bones thicker than a chicken wing, fruit pits, corn husks, artichoke leaves, celery (the fibers wrap around the impeller), coffee grounds in large amounts, grease and oil, pasta and rice in large quantities (they expand with water). Food debris in the disposal can also cause a rotten egg smell from your drain, so keeping it clean matters for more than just preventing jams.
- Keep small utensils and objects away from the drain. A stray bottle cap, twist tie, or small spoon falling in is one of the most common causes of jams.
- Run it regularly. A disposal that sits unused for long periods can develop rust and corrosion that makes it more prone to jamming. Even if you do not have food waste to grind, run cold water and flip the switch every week or two.
- If your shower pressure drops when someone flushes the toilet, it is a related plumbing issue -- shared supply lines affect multiple fixtures.
Related: Why Does My Drain Smell Like Rotten Eggs? · How to Fix a Running Toilet · Why Does My Washing Machine Smell Like Sewage?
Written by Sarah Mitchell
Sarah writes about home improvement and practical DIY topics. She focuses on clear, step-by-step guides that anyone can follow.