How to Troubleshoot a Dishwasher That Will Not Get Dishes Clean

Following the manufacturer's maintenance guidelines helps to ensure your dishes come out clean.

Opening the dishwasher to remove clean dishes only to find there are still soils on some or all of them doesn't mean your dishwasher is defective. Your dishwasher needs hot, clean water and the right detergent to clean your dishes. The water also needs to reach all parts of your dishes to rinse the soils away. Sometimes, a faulty part is to blame for inadequate cleaning, but more often it's a problem easily fixed by cleaning certain elements of your dishwasher.

Things You'll Need

• Meat thermometer
• Pipe cleaner
• Spray arm (if necessary)
• Pressure gauge

Instructions

Water Temperature

1. Turn on your kitchen hot-water faucet and let it run until it is hot. Place a meat thermometer under the stream of water. Most dishwashers require water that is at least 120 degrees Fahrenheit to clean properly.

2. Set your water heater to provide water that is at least 120 degrees Fahrenheit.

3. Avoid running the dishwasher when hot water is in use in another part of your home, such as in the shower or washing machine.

Detergent

1. Fill your dishwasher with detergent intended for use in dishwashers. Dishwasher detergents are designed to create low suds. The wrong type of detergent can result in a lot of suds, which prevents water from reaching your dishes.

2. Store powdered detergent in a cool, dry place. Moist detergent won't dissolve properly and can cake in your dishwasher, making it ineffective at cleaning your dishes.

3. Use only the amount of detergent recommended. Most detergents list this information on the label. Hot water requires less detergent than cold water to clean properly.

Drain Valve

1. Listen for water running through your drain pipes during the wash cycle. If you hear water, the drain is likely plugged.

2. Check the drain valve inside your dishwasher for debris. When draining, this valve opens to drain the dirty water, and when the drain cycle is over, it closes again. If is plugged and cannot close properly, the water will drain during the wash cycle, resulting in dirty dishes.

3. Clean away any debris visibly clogging the drain to allow it to close.

Filter

1. Remove the filter, which is typically located on the bottom of the tub if it is not a self-cleaning filter. Self-cleaning filters do not need to be removed or cleaned.

2. Rinse the filter under hot water to remove debris.

3. Replace the filter and run your dishwasher as usual.

Spray Arms

1. Examine the spray arms which supply clean water and detergent to wash your dishes. If these are clogged, the water and detergent can't get to the dishes to clean them.

2. Insert a pipe cleaner into the spray-arm holes to remove any debris.

3. Replace the spray arm if it is still not functioning properly after cleaning it.

Water-Inlet Valve

1. Listen for a thump or a bang, also called a water hammer, when the dishwasher is changing cycles. This sound is caused by the water-inlet valve closing while water is still flowing in the pipe. The water hits the valve but can't go further.

2. Test the water pressure by attaching a pressure gauge to one water line in your home. If the pressure is over 60 psi, regulate it with a reducing valve.

3. Check the water-inlet valve for sediment buildup. This is connected to the main water line and provides the water to your dishwasher. Without adequate water, the dishwasher can't clean your dishes.

4. Turn off the main water supply and remove the valve to clean it. Replace corroded or otherwise damaged valves.

References

• Frigidaire: Frequently Asked Questions, Dishwashers
• AP Wagner: Why Are the Dishes Still Dirty?