How to Fix a Garbage Disposal. Complete Troubleshooting Guide

You’ll want to check if the disposer fails to start; often, it simply needs a reset. For many issues, your basic toolkit suffices, no need to break out the big guns unless you suspect a faulty circuit breaker trips the power. A few dollars’ worth of parts can save you from calling in an expensive pro.

If the unit loses prime or trips the 15-amp breaker, first ensure the disposer isn’t overloaded by checking for plugged drains and stopping up any blockages. If that doesn’t resolve it, inspect the dishwasher hose connection to make sure nothing is jamming the flywheel, a common cause of jams.

For a stuck flywheel, gently turn off power and water; then remove the lower mounting bolt and access the flywheel directly. Use a wrench to rotate it free without forcing it. If stuck residue persists, a cleaning paste or baking soda mixture can help dissolve debris before proceeding.

Quick diagnosis. what’s your disposal doing?

garbage disposal parts diagram showing internal components

Before grabbing any tools, figure out exactly what’s happening. The symptom tells you the cause, and the fix.

Small detail, real impact.

Find your problem below and jump straight to the fix:

Makes a humming noise but won’t spin? → Fix 2: Unjam the Flywheel
Completely silent when you flip the switch? → Fix 4: Restore Power
Runs but drains slowly? → Fix 3: Unclog the Drain
Leaking water under the sink? → See our guide on leaking disposal repair

Good news: Most disposal problems have a simple fix. Start with Fix 1 below, the reset button solves the majority of issues in about 30 seconds.

Not sure which symptom you have? Turn on the disposal and listen. A humming sound means the motor works but something is blocking it. Complete silence means it’s a power issue. Running normally but backing up means a clog downstream.

What You’ll Need

Gather these before you start:

1/4” Allen wrench, This specific size fits most disposals. Check your junk drawer, one usually comes with the unit.
Flashlight, To see inside the disposal and under the sink
Pliers or tongs, For retrieving objects (never use your hands)
Plunger, A flat-bottom sink plunger, not a toilet flange plunger

You likely won’t need all of these. The reset button fix requires no tools at all.

Fix 1: reset the disposal (30 seconds)

Try this first. The reset button fixes most disposal problems instantly.

If the reset button on your disposal is depressed, push it up to restart. Elsewhere, a motor failure from overload or excessive heat can trip the breaker safeguarding it. Clear any blockage in the drain and confirm that water supply isn’t restricted. To diagnose electrical glitches, use a multimeter priced around $50; essential for pinpointing issues. Ensure your pump meets 10 PSI; anything below suggests problems. If your model’s safety feature trips at 8 amps or above, frequent tripping may indicate malfunctions.

Here’s how:

Turn off the wall switch first; ensure the disposal is powered down. Wait five minutes for any residual heat or a running motor to cool. Next, locate the reset button, typically small and red or black, about the size of a pencil eraser, found on the bottom of your disposal unit under the sink. Press it firmly until you feel a definite click that holds. Test by turning on cold water followed by flipping the wall switch; see if the disposal starts up properly.

If the disposal runs normally, you’re done. If the reset button pops back out immediately or won’t stay pressed, there’s likely a jam that needs clearing first.

For more details, see our complete guide to reset the disposal.

Fix 2: unjam a humming disposal

Symptom: You hear a humming sound when you turn on the disposal. But the blades don’t spin.

This means the motor is working, but something is jamming the flywheel (the spinning plate with the blades). This is the second most common problem after a tripped reset.

Safety First: Turn off the wall switch AND the circuit breaker before working on a jam. Never put your hand inside the disposal, even when the power is off.

Method 1: Allen Wrench (Best Option)

First, find the hex-shaped hole on the bottom center of the disposal; next, insert a 1/4” Allen wrench into it. Rotate the wrench back and forth, feeling for resistance initially; keep rotating until the flywheel moves freely in both directions. Then, use a flashlight to look inside the disposal from above, removing any visible debris with pliers or tongs. After that, press the reset button and restore power before testing by running cold water through the system.

Method 2: Wooden Spoon (No Allen Wrench)

First, insert a wooden spoon handle into the disposal from the top and press it against one of the impeller blades; then push to rotate the flywheel manually. Once you have worked it back and forth until it moves freely, remove any debris, reset the breaker if necessary, and finally test the disposal to ensure everything is functioning properly.

Common jam culprits: Bones, fruit pits, silverware, glass shards, and bottle caps. If your disposal is humming, a jammed disposal is almost always the cause.

Prevention tip: Always run cold water before, during, and after using the disposal. Cold water keeps grease solid so it gets chopped up rather than coating the blades and causing buildup that leads to jams.

Fix 3: unclog a slow-draining disposal

Symptom: The disposal runs, but water drains slowly or backs up into the sink.

A clog is in the drain line below the disposal, not in the disposal itself.

Step 1: Try Running the Disposal

Sometimes debris just needs to be cleared:

Turn on cold water
Run the disposal for 30 seconds
Keep water running for another 15 seconds after turning off the disposal

Step 2: Plunge It

If that doesn’t work:

Fill the sink with about 3-4 inches of water. If you have a double sink, stuff the other drain with a wet rag. With a dishwasher hooked up, clamp its drain hose to avoid backflow. Grab a flat-bottom plunger, no toilet plungers, and give it a good 15-20 pumps. Once done, check for drainage; run the disposal with water to flush out any leftover bits.

Step 3: Clean the P-Trap

For stubborn clogs:

First, place a bucket under the P-trap (the curved pipe under the sink). Next, loosen the slip nuts and carefully remove the trap; then, clean out any debris, grease buildup is quite common. After that, reassemble everything securely and test to ensure there are no leaks.

Warning: Never use chemical drain cleaners like Drano in a garbage disposal. They can damage the seals and create a dangerous splash hazard.

Why does your disposal get clogged? Grease, fibrous items like celery or asparagus, and starchy stuff such as pasta or potato peels can accumulate in the drain beneath the unit, leading to blockages.

Preventing future clogs: Run the disposal with cold water for 15-20 seconds after all food is ground up. Once a week, grind ice cubes to clean the blades, followed by citrus peels to freshen the drain.

For persistent drainage issues, see our clogged disposal guide.

Fix 4: restore power to a silent disposal

Symptom: Nothing happens when you flip the switch, no sound at all.

When a disposal is silent, it’s usually a power problem, not a broken disposal.

Check these in order:

Is it plugged in?, Look under the sink for the outlet. Make sure the plug is secure.
Check the GFCI outlet, Many under-sink outlets are GFCI protected (the outlet with “Test” and “Reset” buttons). Press the Reset button on the outlet itself.
Check the circuit breaker, Go to your electrical panel and look for a tripped breaker. If one is in the middle position, flip it fully off, then back on.
Test the outlet, Plug in a lamp or phone charger. If it doesn’t work, the outlet is the problem, not the disposal.

If the outlet has power but the disposal still won’t run, try the reset button on the disposal itself.

For more on power issues, including when to call an electrician, see our electrical troubleshooting guide.

When to Replace Instead of Repair

Sometimes a disposal can’t be fixed. Here’s how to know when it’s time for a new one:

Signs your disposal needs replacing:

Burning smell, This indicates motor damage. Once you smell burning, the motor is likely done.
Reset button won’t stay in, Even after clearing any jams, if the button keeps popping out, the motor may be burned out.
Age, Disposals over 10 years old are candidates for replacement, especially if they’re having multiple problems.
Leaking from the bottom, This usually means internal seals have failed. Seal replacement isn’t practical, a new unit is more cost-effective.

Cost comparison:

Professional repair: $75-150 (often not worth it)
New disposal: $80-300 depending on power and features
Professional installation: $150-200

If your disposal is old and showing multiple symptoms, replacement usually makes more sense than repair.

Choosing a replacement: A 1/2 HP InSinkErator disposal should suffice for everyday use in most homes, though those who cook often or live in larger households may prefer a 3/4 HP or 1 HP model. Continuous-feed designs are typical and easier to operate; however, batch-feed versions, which require activation by the lid, provide added safety for families with children. Make sure parts and support from InSinkErator or Moen are readily available before making your selection.

DIY vs. professional installation: If you’re replacing an existing disposal with the same size, DIY installation takes about an hour. However, if you need new electrical work or plumbing modifications, hire a professional.

Tools every homeowner should have

Keep these on hand for future disposal issues:

Disposal wrench or 1/4” Allen wrench, For clearing jams. Most disposals come with one, check your junk drawer or under the sink.
Flashlight, Essential for seeing inside the unit and under the sink
Flat-bottom plunger, Different from a toilet plunger. Works better on sink drains.
Basic pliers or tongs, For retrieving dropped items safely

With these four items, you can handle 90% of garbage disposal problems yourself.

FAQ

Can I fix my garbage disposal myself?

Yes. About 90% of garbage disposal problems can be fixed in under 10 minutes with basic tools. The most common fixes, resetting and unjamming, require only an Allen wrench or no tools at all.

Why is my garbage disposal humming but not spinning?

The flywheel is jammed. Something is stuck between the blades and the grinding ring, preventing rotation while the motor runs. Insert a 1/4” Allen wrench into the hole on the bottom of the disposal and rotate back and forth to free it.

How do I fix a garbage disposal that stopped working?

Press the reset button on the unit’s underside; if silent, verify power by ensuring it’s plugged in, resetting the GFCI outlet, and inspecting the circuit breaker. A hum without rotation indicates a jam that demands clearance using an Allen key.

Is it worth fixing an old garbage disposal?

If your disposal is over 10 years old or leaking from the bottom, replacement is the smarter choice. New units cost $80-300 and are more efficient and quieter than older models. For simple issues like jams or resets, fixing is always worth trying first regardless of age.

What can I put in a garbage disposal?

Vegetable trimmings, fruit, cooked meat, bread, and small bones, like chicken bones, are suitable. Steer clear of fibrous foods such as celery or corn husks, starchy items that expand like pasta or rice, grease, oil, and large amounts of coffee grounds. Non-food items are off-limits too.

Why does my garbage disposal smell bad?

Clean odors by addressing residue in blades and grinding chamber. Start by dumping half a cup of baking soda into the disposer, followed by a full cup of white vinegar; allow it to fizz for ten minutes before rinsing with hot water as you run the disposal. For continuous freshness, incorporate citrus peel grinding into your weekly routine.