If your garbage disposal hums but will not turn, it is jammed. If it does nothing at all, it has tripped and needs resetting. Those two symptoms account for almost every disposal call, and both are usually fixable in ten minutes without a plumber.
The reset button on a garbage disposal is a small red or black button on the underside of the unit, near the bottom. Most people never know it exists until something goes wrong.
Here is how to tell which problem you have, how to fix each one safely, and the point at which replacing the unit genuinely is the better answer.
Work out which fault you have first
| What happens when you switch it on | What it means | Fix |
|---|---|---|
| Nothing at all, no sound | Tripped internal overload | Press the disposal reset button |
| Humming but not turning | Jammed impeller | Free the jam, then reset |
| Turns but drains slowly | Blockage in the waste pipe | Clear the trap |
| Loud grinding or rattling | Foreign object inside | Remove it |
| Water leaking underneath | Failed seal or cracked body | Usually replacement |
| Trips the breaker every time | Electrical fault | Stop, call an electrician |
The last two rows are the ones where a home fix runs out. Everything above them is normally a job you can do yourself.
Before you do any of it: switch the disposal off at the wall switch, and unplug it or turn off its breaker. Never put your hand into the chamber while it has power. This is the one non-negotiable part of this article.
The reset button on a garbage disposal
Every unit has a thermal overload cut-out. When the motor draws too much current, usually because it is straining or jammed, the overload trips and cuts power to protect the motor. That is a safety feature working correctly, not a failure.
To reset it:
- Switch the disposal off at the wall, and cut power at the breaker
- Reach under the sink and find the small red or black button on the base of the unit
- Press it firmly. You should feel a click as it seats
- Restore power and try the disposal again
If the button will not stay in, the motor is still too hot. Leave it fifteen minutes and try again.
If it resets and then trips again within seconds, the unit is still jammed. Resetting a jammed disposal repeatedly will burn the motor out, so deal with the jam first.
Freeing a garbage disposal that is humming
A humming disposal has power and the motor is trying to turn, but something is stopping the plate from rotating. Usually a fruit pit, a bottle cap, a piece of cutlery, or fibrous waste wound tight around the impeller.
With the power off at the breaker:
Use the hex key. Most disposals have a hex fitting in the centre of the underside. The key that came with the unit fits it, and a quarter inch hex key works if that is long gone. Turn it back and forth until it moves freely through a full rotation. That breaks the jam.
If there is no hex fitting, put a broom handle or a wooden spoon into the chamber from above, brace it against the impeller, and lever it round. Wood, not metal, and not your hand.
Look inside with a torch before you restore power, and take out whatever caused it with pliers or tongs.
Then press the reset button, restore power, and run cold water while you switch it on.
Cold water, not hot. Hot water melts fat, which then travels down the pipe and sets again further along where it is much harder to reach.
What causes jams, and what to keep out
Disposals do not have blades. They have blunt impellers that fling waste against a grind ring. Anything that wraps, expands or does not break apart causes trouble.
Keep out:
- Coffee grounds, which pack down like wet sand in the trap
- Eggshells, for the same reason
- Potato peel and rice, which turn to paste
- Celery, artichoke and onion skins, which wrap around the impeller
- Fat, oil and grease, which set in the pipe downstream
- Bones and fruit pits, which jam it outright
The most common single cause we see is grease, because the damage is invisible until the drain backs up months later.
Slow draining after the disposal runs
If the unit spins freely but the sink drains slowly, the disposal is fine. The blockage is in the trap below it.
Put a bucket under the P-trap, undo the slip nuts by hand, and take the trap off. It is usually full. Clean it out, refit it, and run water through.
If the trap was clear, the blockage is further along the branch pipe, which is where it stops being a five minute job.
One thing worth checking if you also have a dishwasher: if the dishwasher drains into the disposal and it was recently installed, make sure the knockout plug inside the disposal inlet was removed. If it was not, the dishwasher cannot drain, water stands in the tub, and it starts to smell. That connection catches a lot of people out after a kitchen refit.
Replacing a garbage disposal
Some faults are not worth repairing. Replacing a garbage disposal makes more sense than fixing one when:
- Water is leaking from the body of the unit rather than a connection
- The motor hums after a proper reset and the impeller turns freely
- It trips the breaker rather than its own reset button
- It is over ten years old and failing repeatedly
- The grind chamber has rusted through
| Fault | Repair or replace |
|---|---|
| Tripped overload | Reset, no cost |
| Jammed impeller | Free it, no parts needed |
| Leak at a pipe connection | Repair, usually a seal or gasket |
| Leak from the body itself | Replace |
| Motor dead after reset | Replace |
| Broken garbage disposal blades | Replace, the impellers are not sold separately |
That last one is worth clearing up, because people search for it often. Disposals do not have replaceable blades. The impellers are part of the rotating assembly inside a sealed unit, and if they have snapped or worn away the unit is finished.
When to call somebody
Call a professional if:
- The unit trips the household breaker rather than its own reset button
- There is water leaking from the body of the disposal
- The sink still drains slowly after the trap has been cleaned
- You have reset and unjammed it and it still will not run
- There is a burning smell from the motor
A disposal that trips the breaker is an electrical fault, and that one is worth taking seriously rather than resetting repeatedly.
Frequently asked questions
Where is the reset button on a garbage disposal?
On the underside of the unit, near the bottom centre. It is small, usually red, sometimes black, and it sits slightly proud when tripped.
Why does my garbage disposal hum but not turn?
It is jammed. The motor has power and is trying to turn, but something is blocking the impeller. Cut the power, free it with a hex key from underneath, remove the object, then reset.
Can I use chemical drain cleaner in a garbage disposal?
Better not to. It sits against the metal components rather than flushing through, and if it does not clear the blockage anybody working on the pipe afterwards is dealing with caustic water. Clear the trap by hand instead.
How long does a garbage disposal last?
Eight to fifteen years for most household units. Hard water and heavy grease use shorten that. Units that are reset frequently, meaning they are being overloaded regularly, tend to fail earlier.
Should I run hot or cold water when using it?
Cold, every time, and keep it running for a few seconds after the noise stops so waste is carried right through the pipe rather than left sitting in the trap.
My disposal smells. Is it broken?
Usually not. Smell comes from food residue in the chamber and under the splash guard. Lift the rubber guard and clean the underside, which is the part everyone misses. If the smell is coming from the dishwasher rather than the disposal, that is a different problem with its own causes.
Getting it sorted
Most disposal problems come down to a reset button nobody knew was there, or a fruit pit wedged against the impeller. Both are ten minute fixes.
Where it matters is what a jammed disposal does to everything connected to it. A blocked disposal stops a dishwasher draining, and a dishwasher that cannot drain starts to smell and eventually leaks. If your dishwasher has gone wrong at the same time, our guide on why a dishwasher smells covers that connection.
AGA Appliance Service provides dishwasher repair and full appliance service across 29 cities in 7 counties in the Charlotte metro and northern South Carolina, including appliance repair throughout Mecklenburg County. For the plumbing side of a disposal replacement you may want a plumber, and we will tell you plainly if that is what you need rather than charging you to find out.
There is a $79 diagnostic fee, waived when you approve the repair, and every repair carries a 90-day parts and labor warranty. We are open 9 AM to 8 PM, seven days a week, and same-day service is available on bookings placed before 11 AM. Call (704) 904-2007 or book a visit online.