Why Is My Garbage Disposal Humming?

Many households rely on a garbage disposal to break down a variety of soft and liquid food items, such as citrus fruit peels, which can also help to freshen up the scent of the disposal. However, before you put anything into the garbage disposal, you need to make sure that it is working properly to avoid damaging the blades or the motor.

So, if the garbage disposal starts to hum when you turn it on, it's important to find out why the disposal is making this noise and how to fix the problem. Common issues that can cause the disposal to hum include a clog that is preventing the blades from turning, an overheated motor, or even a physical obstruction, like a fork or spoon. Use this guide to learn why the garbage disposal is humming and what you can do to resolve the issue.

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Obstructed Blades

A garbage disposal isn't full of razor-sharp blades that can cut and slice through anything. If you or someone else in your home puts any items into the disposal that the appliance is not designed to handle, like cutlery or a child's toy, then it can obstruct the movement of the blades. When the switch is flipped to turn the garbage disposal on, the electricity will still run to the motor and the motor will still try to turn the blades, resulting in a loud humming sound.

You can fix this problem by turning off the garbage disposal and disconnecting it from the power source by flipping the associated circuit breaker. Once the garbage disposal is safely disconnected, use a pair of metal tongs to reach into the disposal and retrieve the object causing the obstruction. Depending on the object, you may need a set of long needle-nose pliers to grip the item and pull it out of the disposal.

Do not stick your hand or fingers into the disposal. After pulling the item out, reconnect the disposal and run cold water into the sink. Turn on the disposal and verify that it is working properly. Keep in mind that if you keep try to use an obstructed disposal, the motor may burn out.

Clogged Disposal

Similar to putting a fork or spoon into the disposal, if you regularly add food or items that the garbage disposal is not made to handle, like coffee grounds, hot grease, or clam shells, then a clog can form that prevents the blades from moving. The motor still receives electricity when the switch is turned on, but because the blades are stuck, the disposal does not work. Instead, it creates a low humming sound that should indicate there is a problem.

Turn off the garbage disposal and disconnect it from the home's power by flipping the associated breaker switch. Next, insert an Allen key into the hole at the bottom of the garbage disposal and gently rotate it back and forth to loosen the clog. Running cold water helps to lubricate the inside of the disposal and break up the clog.

Use a flashlight to confirm that the bulk of the clog has been removed, then reconnect the unit and turn the garbage disposal back on to verify that it is operating freely without humming. Avoid putting food items into the disposal that can cause clogs, like grease, oil, coffee grounds, seeds, stringy fruit, fibrous vegetables, and tough shells.

Disposal Needs to Be Reset

Garbage disposals come with a reset switch that is typically located on the bottom of the unit. If you have made sure that there aren't any problems with clogs or obstructions and the garbage disposal continues to make a humming sound when you use it, then you may just have to reset the disposal.

Inspect the reset switch on the bottom of the garbage disposal to make sure that it isn't worn out or faulty, then press the switch to reset the garbage disposal. Run cold water into the sink and turn the disposal on to verify if this simple fix worked.

Tripped Breaker or GFCI Switch

In some cases, the garbage disposal blades won't rotate and the motor will make a humming sound when the GFCI outlet or circuit breaker has tripped. Generally, a tripped circuit breaker is due to an electrical problem, like a short circuiting connection. GFCI outlets may trip if the garbage disposal is overheating, so it's a good idea to check whether there is a physical obstruction or a clog that could have caused the disposal to overheat.

If the wiring and the disposal look fine, simply reset the GFCI switch with the reset button or reset the breaker to restore power to the garbage disposal. Run cold water into the sink and turn the disposal on to check whether the unit is still humming or if the problem has been resolved. If the garbage disposal is still humming, then the tripped breaker or GFCI switch is just a symptom of a larger problem that you will need to investigate.

Overheating Unit

Another potential issue that could be causing the garbage disposal to make a humming sound is if the motor is overheating. This can happen if the motor is faulty, if the blades are too dull to properly grind the food items, or if you are putting items into the disposal that the unit is not designed to handle. The disposal may also overheat if you have been using it for an extended period without taking a break.

The first steps to fixing this issue is to figure why the disposal is overheating. Start by turning the disposal off and allowing it to cool down. After about 20 minutes, turn the disposal back on and test to see if it will start humming or overheating again. If the disposal starts to overheat when you put acceptable items into it, then the blades may be too dull, causing the motor to work harder in order to fulfill the same function.

Try sharpening the blades by putting ice cubes and salt into the disposal. These coarse materials help to refine the edge on the blades, though the result may not be enough to resolve the overheating problem because blades wear out over time. Similarly, if the disposal is overheating because of a faulty motor, then the blades can be razor sharp, but it won't stop the garbage disposal from overheating.

At this point, it's recommended to hire a professional plumber to repair or replace the garbage disposal. Consider the age of the unit and whether there have been any previous problems to decide on the best course of action.

Faulty Motor

Unfortunately, a humming garbage disposal can be a sign that there is a more serious situation that you have to deal with, like a faulty motor. If you have checked the disposal with a flashlight to make sure that there isn't a clog or an obstruction, then the problem may be a faulty motor. A faulty motor may be the result of a problem with the wiring, which could trip the GFCI switch or the breaker switch.

Garbage disposals tend to last about 10 to 15 years, so if your unit is approaching the end of its life, a faulty motor is a sign to have the entire disposal replaced. You may be able to find a technician that can replace just the motor, but in most cases, it is more cost effective to purchase a new garbage disposal. Contact a professional plumber to get a quote so that you can make the right decision for your home.

Garbage Disposal Safety Tips

One of the best ways to prevent the garbage disposal from humming is to ensure that you take care of it properly. You should only put items into the disposal that the unit can handle, so it's important to avoid adding hot grease, oil, coffee grounds, seeds, stringy fruit, fibrous vegetables, and hard shells to the disposal.

Additionally, you should always run cold water when you are using the disposal. This helps to solidify and fatty foods, making it easier for the blades to cut through the food scraps instead of getting clogged with partially melted grease and fats.

Regardless of the problem, never stick your hand or fingers into the garbage disposal. Always make sure the power to the unit is off before trying to clear a clog or pull out a physical obstruction and do not try to clear a clog in a garbage disposal with a chemical cleaner. Not only are these cleaners hazardous to your plumbing system, they may not be able to remove the clog immediately. Instead, the chemicals sit in the disposal and may spray out when the unit is turned on.