Garbage Disposal Humming but Not Working? How to Fix It

A garbage disposal humming but not grinding almost always means the motor is getting power but the spinning plate inside can’t turn. Most of the time something is wedged between the plate and the grinding ring, and you can free it in about 15 minutes with the small hex wrench that came with the unit. If that doesn’t work, the motor itself may be worn out, and that’s when replacement makes more sense than repair.

TL;DR

Turn the disposal off right away. Letting it hum heats the motor and trips the overload protector.
Cut power by unplugging the unit under the sink or switching off its circuit breaker, not just the wall switch.
Put a hex wrench (usually 1/4 inch) in the socket at the center of the bottom of the unit and work it back and forth until it turns freely.
Pull out whatever caused the jam with tongs or needle-nose pliers. Never use your hand.
Let the motor cool, press the red reset button on the bottom, then test. If it still hums with a free-turning shaft, the motor is likely failing.

Why a Garbage Disposal Hums
Symptom and Cause Chart
How to Fix a Humming Garbage Disposal
What Not to Do
When to Call a Professional
How to Prevent It
FAQ

Why a Garbage Disposal Hums

A disposal doesn’t have sharp blades. Inside is a spinning metal plate (often called the flywheel or turntable) with two small swiveling lugs called impellers. The motor spins the plate, and the impellers fling food against a stationary grinding ring until it’s small enough to wash down the drain.

The hum you hear is the motor trying to start. When the plate can’t move, the motor gets electricity but can’t spin, so it just buzzes and heats up.

A Jammed Flywheel

This is the cause in most cases. Moen’s support guide points to bones and stringy waste such as corn husks as common culprits that lodge in the grinding mechanism. Fruit pits, a stray bottle cap, a twist tie, or a spoon that slipped down the drain can do the same thing.

Waste King also lists other signs of a jam: a sound that’s different from the normal grinding noise, food visible at the splash guard, and a rotten smell coming from the sink.

A Tripped Overload Protector

Every major brand builds in a thermal overload protector, the red reset button on the bottom of the unit. When the motor overheats, usually from a jam or a long run time, the protector cuts power to keep the motor from burning up.

A tripped protector usually means silence, not humming. But the sequence is common: the disposal hums, you flip the switch a few more times, and then it goes quiet. Moen notes that repeated restart attempts on a jammed unit are what trip it.

A Burned-Out or Failing Motor

If you clear the jam, the hex wrench spins the shaft freely, and the unit still only hums, the problem is likely inside the motor. Older units that have been jammed many times, or ones that were left humming for long stretches, are the most likely to fail this way.

A disposal motor isn’t a homeowner repair. At that point the choice is a service call or a new unit, and for most households replacement is the practical answer.

Symptom and Cause Chart

Symptom	Likely cause	DIY or pro?
Hums when switched on, no grinding	Object jamming the flywheel	DIY: hex wrench and tongs
Hummed, then went completely silent	Overload protector tripped after a jam	DIY: clear jam, cool down, press reset
Silent, reset button already pressed	Tripped breaker or unplugged unit	DIY: check plug and breaker
Reset button won’t stay in	Motor still hot, or jam not cleared	DIY: wait 10 minutes, recheck jam
Hums even though the shaft turns freely by hand	Failing motor	Pro or replace the unit
Breaker trips every time you run it	Electrical fault in the unit or circuit	Pro: electrician or plumber
Burning smell, smoke, or water dripping from the bottom	Internal motor or seal failure	Pro or replace the unit

How to Fix a Humming Garbage Disposal

Tools you’ll need: the hex wrench that came with your disposal (InSinkErator and KitchenAid call it a “wrenchette”) or a standard 1/4-inch Allen wrench, a flashlight, long-handled kitchen tongs or needle-nose pliers, and safety glasses. A wooden spoon handle or a disposal unjamming wrench that works from above is a useful backup.

Safety note: The motor can start the instant it gets power. Every step below assumes the power is disconnected, not just switched off at the wall.

Step 1: Turn It Off and Stop Retrying

Flip the wall switch to off as soon as you hear the hum. Each extra attempt pushes more heat into a motor that can’t move.

Turn off the faucet too. KitchenAid’s instructions have you shut off the cold water before clearing a jam.

Step 2: Cut Power at the Plug or Breaker

Look under the sink. Many disposals plug into an outlet in the cabinet, and unplugging the cord is the easiest way to make sure the motor can’t start.

If yours is hardwired, with a cable running into a metal box on the unit instead of a plug, go to your electrical panel and switch off the breaker labeled for the disposal. Flip it fully to off; don’t open the panel cover or touch any wiring.

Before you go further, test it: flip the wall switch on for a second. If you hear nothing at all, the power is truly off. Then return the wall switch to off.

Step 3: Look for the Obstruction

Pull out the rubber splash guard if it lifts out, and shine a flashlight down the drain opening. You’re looking for anything hard sitting on the plate or wedged at its edge: a bone, pit, bottle cap, or piece of silverware.

Don’t be surprised if you can’t see the culprit yet. It often only becomes visible once the plate moves.

Step 4: Turn the Hex Socket on the Bottom

On the bottom of the disposal, in the center, is a small six-sided socket. It connects directly to the motor shaft, so turning it turns the flywheel by hand.

Insert the hex wrench and rock it back and forth. It will feel stiff at first, then give as the jam breaks loose. InSinkErator and KitchenAid both say to keep working it until it makes one full revolution; Moen’s guide aims for at least two free turns.

Don’t have the original wrench? This Old House notes that a standard 1/4-inch Allen wrench fits most units. If your model has no bottom socket, use an unjamming wrench or a wooden spoon handle from above to rotate the plate, as Moen and Waste King describe.

Step 5: Remove the Object With Tongs

Once the plate turns, shine the light back in. Grab whatever was causing the jam with long-handled tongs or needle-nose pliers and lift it out.

Check around the full edge of the plate, since small pieces like glass or pits can hide under the impellers. Remove every tool from the sink opening before moving on.

Step 6: Let the Motor Cool

If the disposal hummed for a while, its motor is hot. KitchenAid recommends letting it cool for 3 to 5 minutes before pressing reset.

InSinkErator says its EZ Connect models may need up to 20 minutes of cooling, with the switch off or the unit unplugged, before they’ll run again.

Step 7: Press the Reset Button

Find the red button on the bottom of the unit, near the hex socket. According to InSinkErator, a tripped button sits about 1/4 inch lower than normal.

Press it gently until it clicks. On some Moen models it’s recessed, and Moen suggests using a screwdriver to reach it. If it won’t stay in, InSinkErator advises waiting about ten minutes and trying again.

Step 8: Restore Power and Test

Make sure nothing is in the sink opening and no one has a hand near it. Plug the unit back in or switch the breaker back on.

Run a strong stream of cold water, then flip the switch on. A healthy disposal starts with a steady whir right away.

If it’s still silent, check whether the breaker has tripped again. If your breaker keeps flipping off, our guide on why a circuit breaker keeps tripping explains what that means and when it’s an electrician’s job.

Step 9: If It Still Hums, Check the Motor

Disconnect power again and turn the hex wrench. If the shaft spins freely but the unit still hums when powered, the jam is gone and the motor is the problem.

If the shaft won’t budge no matter how you work it, something is wedged deeper than you can reach. Moen suggests repeating the steps once more, and if that fails, calling for service.

What Not to Do

Never put your hand in the disposal. Even with the power off, the grinding ring and debris can cut you, and a missed breaker can turn a jam into an injury.
Don’t keep flipping the switch. A humming motor is a motor overheating. Repeated tries trip the protector and shorten the motor’s life.
Don’t pour chemical drain cleaner into it. Waste King lists caustic drain cleaners among the things to keep out of a disposal, and they won’t clear a mechanical jam anyway.
Don’t strike the reset button. InSinkErator warns against hitting it with objects. A gentle press is all it takes.
Don’t open the electrical cover or touch wiring. Your part stops at unplugging, switching off the breaker, and pressing reset.
Don’t force a stuck wrench with a long pipe or hammer. Steady back-and-forth pressure works; brute force can crack the housing or strip the socket.

When to Call a Professional

You’ve done everything a homeowner should do once you’ve cleared the jam, pressed reset, and checked the breaker. Call a plumber, or an electrician for wiring issues, if you notice any of these:

The shaft turns freely but the unit still hums when switched on.
The breaker trips every time you run the disposal.
You smell burning or see smoke from under the sink.
Water drips from the bottom of the unit or the reset button area.
The jam won’t clear after two rounds of the hex wrench.
You’re pressing the reset button every week or two.

Repair or replace? The Home Depot says a well-maintained disposal can last around 10 years, and lists frequent resets, clogs, odors, unusual noises, and leaks as signs it’s time for a new one. If your unit is near that age and the motor is humming without turning, replacement is usually the better spend.

For cost, The Home Depot puts its disposal installation service at $97 to $339, with an average of $189, depending on the unit, brand, and location. Its installers remove the old unit and connect the new one to existing plumbing and power, but they won’t add a new electrical box.

How to Prevent It

Most jams come from what goes in. Waste King advises keeping these out of the disposal: large whole bones, clam and oyster shells, whole corn husks, glass, china, plastic, bottle caps, tin, aluminum foil, utensils, hot grease, and other hot liquids.

InSinkErator is firm on one item: no fats, oils, or grease, in the disposal or any sink drain. Grease builds up in pipes and causes many of the plumbing problems people blame on the disposal, including a sink that drains slowly.

Coffee grounds and eggshells won’t hurt the grinder, according to InSinkErator, but they act like sediment. Feed them in slowly with plenty of cold water, especially if your pipes are older.

A few habits help the motor too:

Run a strong flow of cold water before, during, and for a few seconds after grinding.
Feed food in gradually instead of stuffing the chamber. InSinkErator lists overloading as the reason the protector trips frequently.
Use the sink stopper when the disposal isn’t running, so silverware and caps can’t fall in.
Run the disposal regularly so food doesn’t sit and harden on the plate.

Food that sits in the chamber also causes odors. If your sink smells even when the disposal works fine, see our guide to getting rid of drain smell. And because many dishwashers drain through the disposal, a clogged unit can back up into it; our dishwasher not draining guide covers that connection.

FAQ

Why is my garbage disposal humming but not working?

The motor is getting power but the flywheel inside can’t spin. Usually a bone, pit, or small object is wedged against the grinding ring. Cut the power, free it with a hex wrench in the bottom socket, and pull the object out with tongs.

What size Allen wrench fits a garbage disposal?

Most disposals take a 1/4-inch hex (Allen) wrench in the socket on the bottom. Many units ship with a matching wrench. Check your manual if the 1/4-inch size doesn’t seat snugly.

Where is the reset button on a garbage disposal?

It’s a small red button on the bottom of the unit, facing the floor. When tripped, it sits slightly lower than normal. Let the motor cool for a few minutes, then press it gently until it clicks.

Can a humming garbage disposal burn out?

Yes, if it’s left humming or restarted over and over. A stalled motor builds heat fast, which is why the overload protector cuts power. Turning it off quickly and clearing the jam is the best way to protect the motor.

Should I repair or replace a humming garbage disposal?

If clearing the jam fixes it, keep using it. If the shaft turns freely and it still hums, or it leaks or trips the breaker, replacement is usually the better choice. That’s especially true for a unit approaching 10 years old.

Why Your Garbage Disposal Is Humming (And How to Fix It)