How To Fix A Humming Or Buzzing Dishwasher

Most dishwashers will emit a quiet buzz or hum when they are running efficiently. It is only when this low-grade vibration becomes louder or more discordant that you should investigate further. 

Here is a helpful guide showing you how to identify and resolve the issue before your machine suffers irreparable damage. 

7 Reasons Your Dishwasher is Buzzing or Humming

The following section pinpoints the seven most likely reasons for your dishwasher’s unusual sounds. 

For each potential reason, I have outlined the probable cause and the problems that could occur if left unchecked. In addition, you will also find a set of comprehensive steps that will help you to solve the issue.

1. Are Dishes Are Stacked Incorrectly?

Many people stack dishes incorrectly in their dishwasher, which often culminates in a buzzing noise caused by your dishes knocking into each other and impeding the smooth function of your machine. 

Dishes and plates may also become chipped when this happens, which is an added irritation. 

Solution: Your dishwasher has designated slots for plates, dishes and cutlery. It is easy to misplace them – especially if you are in a hurry – but it is vitally important to place them in their respective sections and with enough space to avoid overcrowding. 

Lighter-weight items are especially vulnerable to becoming displaced during a wash, so pay special attention to these overlooked utensils. 

Ensure that everything is securely in its correct place before beginning your wash. 

2. Is Your Dishwasher Level?

Another reason for your dishwasher’s loud humming noise may be that it is at an angle or misaligned when placed. 

This may not seem important, but over time, the extra pressure that some of the parts are experiencing may wear out the mechanics. 

Solution: Fortunately, dishwashers often come with adjustable feet, which can be twisted clockwise or counterclockwise to raise or lower each corner.

Using a spirit level to check if your dishwasher is positioned evenly is a good idea. If it’s not, adjust the dishwasher feet until it is uniformly balanced. 

If this undistributed weight has been the cause of the humming, you will see an immediate improvement. 

3. Are Spray Arms Hitting Dishes?

Sometimes, your dishes may extend beyond the racks, leading to them being hit by the spray arms during the cycle, creating a humming noise. This could cause damage to the spray arms, such as cracking or chipping, as well as warped nozzles, leading to a build-up of excessive water pressure. 

Solution: Before starting a wash cycle, ensure that dishes do not extend beyond the rack and make sure that the spray arms can rotate freely. If not, adjust the dishes so that they do not extend beyond the rack so that the spray arms are protected. 

4. Have Items Fallen To The Bottom of Dishwasher?

Smaller-sized utensils or other objects often fall to the bottom of the dishwasher, and this could cause a buzzing sound when hit by the spray arms. 

Items which have fallen to the dishwasher’s bottom may also be sucked into the pump, causing a blockage. This impedes water flow as well as putting a strain on the pump. 

If this continues, the increased strain can cause the pump to wear out prematurely or even fail altogether, leading to avoidable costly repairs or complete replacement.

Solution: Make sure you regularly check the bottom of your dishwasher thoroughly before and after each cycle. Removing fallen items promptly will prevent them from circling by the spray arms.

5. Is the Filtration or Food Grinding System Clogged?

A clogged filter or food grinder can cause the dishwasher’s motor to work harder. This results in vibrations, which manifest as discordant noise. 

This noise may increase incrementally over time if not dealt with. Eventually, your dishwasher will fail to clean correctly, and it may break down altogether. 

Solution: Regularly clean your dishwasher’s filter, ensuring all food particles are removed. If your machine has one, examine the food grinder and remove any obstructions. 

Your particular make and model of the dishwasher will have a manufacturer’s guidelines detailing the proper cleaning instructions.

6. Is the Pump Intake Clogged?

The loud humming may also be because the pump struggles due to a blockage. If allowed to continue unchecked, this could lead to motor burnout.

Solution: Regularly inspect the pump intake for any blockages. You may need to remove the lower spray arm and the filter system to reach the pump intake and examine it thoroughly. 

Remove any visible debris carefully, being mindful not to damage any of the components. 

7. Have the Pump Seals Dried Out?

If the pump seals have become dry, they will create friction during operation, leading to a grinding noise. 

Constant friction wears down the seals and causes pump overheating and deterioration. 

Solution: Pump seals should always be moist. You might need to lubricate these seals manually if you hear a grinding noise. 

You’ll need to locate the circulation pump in your dishwasher; this is almost always located at the base. 

Apply a small amount of silicone-based lubricant to the seals; this will ensure smooth function and protect them from further damage. 

Note: Be sure that the dishwasher is unplugged before performing this task.

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If You Still Have Not Found the Cause of the Buzzing or Grinding

Sometimes, the cause of the noise isn’t immediately evident. It could be related to more complex internal issues requiring professional inspection.

The Dishwasher Makes a Grinding Noise When Starting Up.

This could indicate a faulty motor or pump. It might be necessary to have these components inspected and potentially replaced by a professional technician.

The Dishwasher Makes a Buzzing Noise When Off.

An electrical fault may be causing this noise. Unplug your dishwasher immediately and seek professional help. This can prevent potential fire hazards and protect your appliance from severe damage.

FAQ Dishwasher Making Loud Noises

The dishwasher makes a loud humming noise.

A slight humming sound is typical and indicates that the motor is running smoothly. However, if this becomes unusually loud or persistent, it could mean a problem, such as a clogged pump or a faulty motor.

What does a bad motor on a dishwasher sound like?

A faulty motor will make a loud humming or grinding noise. If your dishwasher has begun to sound unusually loud or seems to be vibrating excessively, it is pretty likely that the motor is struggling. In such cases, professional inspection is recommended to identify the cause definitively. 

Once the cause has been established, you can either replace the faulty parts or replace the entire machine if the problem has escalated beyond all repair.

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HomeServe – Dishwasher Noise

Appliance Service Technician | Website | + posts

Andy has over 8 years of experience working on residential household appliances, performing diagnostics, and repairs across most major brands. He graduated from the Denver Institute of Technology, is NASTeC certified, and has worked for Mr. Appliance. Andy has contributed to features on major publications including Better Home & Gardens, Family Handyman, and