A dishwasher making unexpected noise during a cycle is a common household concern, often signaling an underlying issue ranging from trapped debris to a failing component. Modern dishwashers are engineered to be relatively quiet, so any sudden grinding, rattling, or humming demands attention to prevent more significant damage or a complete breakdown.
Common Sources of Dishwasher Noise
Identifying the specific type of sound is the first step in diagnosing the problem. Different noises point to different potential causes within the machine's complex mechanics.
Grinding or Screeching Sounds
A loud grinding noise typically indicates a foreign object lodged in the drain pump or spray arm. Small items like broken glass, utensils, or even food debris can become trapped and grind against the pump impeller. In some cases, insufficient water supply can cause the pump to run dry, creating a high-pitched screech that requires professional assessment to avoid burning out the motor.
Rattling or Clanking Noises
Loose items inside the dishwasher are the usual suspects for rattling sounds. This often occurs when dishes, cookware, or utensil holders are not properly secured on the upper rack. During the wash cycle, these items can shift and collide with each other or the interior walls, creating a hollow clatter. A less common cause is a loose spray arm striking the upper rack.
Water Flow and Pump Related Sounds
The pump and motor are the heart of the dishwasher, and their operational sounds can indicate health or hidden trouble.
Humming or Buzzing
A steady hum is normal as the motor and pump circulate water. However, a buzzing that persists after the cycle ends often points to a drainage problem. Clogged filters or an obstructed drain hose prevent water from flowing out, causing the pump to work overtime. Checking and cleaning the filter assembly usually resolves this specific buzzing issue.
Squealing or High-Pitched Noise
New dishwashers may produce a slight squeal due to the initial running-in period. For established machines, however, this sound often signals worn-out motor bearings. As the lubrication degrades, the friction increases, creating a high-pitched whine that requires a technician to replace the component.
Mechanical and Installation Issues
Not all noise originates from the internal mechanics; sometimes the issue lies in how the machine is situated within its space.
Vibrations and Rumbling
If the dishwasher is not level, it can rock slightly during the spin cycle, causing it to bang against the countertop or floor. Additionally, worn-out or loose inlet valve solenoids can create a loud buzzing or rattling sound as they regulate water intake. Ensuring the machine is perfectly level with the legs adjusted can eliminate rumbling caused by instability.
Splash and Surge
As water jets blast through the spray arms, the sudden force and surge of water can sometimes cause the tub to "surge" or hit the sides of the cabinet. This results in a loud sloshing or banging sound. Placing insulated noise-reducing panels or towels in the adjacent cabinet can help absorb these vibrations while you determine if a pump check valve is malfunctioning.
Troubleshooting and Solutions
Homeowners can perform several checks to resolve minor noise issues without calling a professional.
| Step | Action | Purpose |
| 1 | Remove the bottom rack and inspect the filter. | Clear food debris that restricts water flow. |
| 2 | Inspect the spray arms for blockages. | Ensure water jets are unclogged by debris. |
| 3 | Check the interior for loose items. | Secure or remove objects that can rattle. |
| 4 | Run a short cycle with vinegar. | Dissolve mineral buildup in the pump and pipes. |
| 5 | Verify the dishwasher is level. | Prevent excessive vibration and movement. |