Why Does My Dishwasher Wash Badly or No Longer Wash?

Jul 19, 2023, 15:36pm

The program to run on your dishwasher will depend on how dirty the dishes are. It will be necessary to use a high temperature for very greasy stains and conversely, a low temperature for lightly soiled dishes.

However, sometimes your dishes are still dirty after a wash cycle at the right temperature. If your dishwasher is no longer washing well, start with some simple checks:

  • Check the water flow
  • Check the tank filter
  • Add salt and rinse aid
  • Check the spray arms

You can then test other parts of the dishwasher:

  • Check the circulation pump
  • Measure the capacitor
  • Check the heating resistor
  • Test the temperature probe
  • Test the pressure switch
  • Descale your dishwasher

This may solve your problem of a dishwasher that no longer washes.

A dishwasher that washes dishes poorly or stops washing altogether can be a frustrating problem. It not only affects the cleanliness of your dishes but also adds extra work to your kitchen routine. There are several common reasons why a dishwasher may wash badly or cease to wash, and understanding these factors is crucial for effective troubleshooting. In this article, we will explore some of the most common causes of poor dishwasher performance and provide guidance on how to address them.

Why Does My Dishwasher Wash Badly or No Longer Wash?

1. Clogged Spray Arms

One of the primary causes of poor dishwasher performance is clogged or blocked spray arms. The spray arms distribute water and detergent to clean the dishes effectively. If they are clogged with debris or mineral deposits, the dishes won’t be properly cleaned. Here’s what you can do:

  1. Remove the Spray Arms: Locate the spray arms in the dishwasher and remove them carefully.
  2. Clean the Spray Arms: Use a soft brush or toothbrush to clean the spray arms thoroughly. Pay attention to the nozzles and remove any clogs or debris that may be obstructing the water flow.
  3. Clear the Holes: Ensure that the small holes on the spray arms are clear of any buildup or residue. You can use a toothpick or a thin wire to gently clear any blockages.
  4. Reinstall the Spray Arms: Once cleaned, reattach the spray arms securely in their original position.

2. Clogged Filters

Dishwashers are equipped with filters that trap food particles and debris during the wash cycle. Over time, these filters can become clogged, affecting the dishwasher’s performance. Here’s what you can do:

  1. Locate the Filters: Refer to your dishwasher’s manual to locate the filters. They are typically found at the bottom of the dishwasher, near the spray arms.
  2. Remove and Clean the Filters: Take out the filters and rinse them under running water. Use a soft brush to scrub away any stubborn residue or particles. Ensure that all debris is removed from the filters.
  3. Clean the Filter Housing: While the filters are removed, clean the filter housing as well. Use a damp cloth to wipe away any buildup or residue.
  4. Reinstall the Filters: Once the filters and filter housing are clean and dry, reinstall the filters securely.

3. Insufficient Water Supply

If your dishwasher is not receiving enough water, it may struggle to wash the dishes effectively. Here’s what you can do:

  1. Check the Water Supply Valve: Ensure that the water supply valve, usually located under the sink, is fully open. If it is partially closed, open it fully to allow adequate water flow.
  2. Inspect the Water Inlet Valve: The water inlet valve controls the water flow into the dishwasher. If it is clogged or malfunctioning, it may not allow enough water into the dishwasher. Consult your dishwasher’s manual or a professional technician to inspect and replace the water inlet valve if necessary.
  3. Verify the Water Pressure: Ensure that your home’s water pressure is adequate. Low water pressure can hinder the dishwasher’s performance. Consult a plumber if you suspect low water pressure in your home.

4. Improper Loading

Improper loading of dishes can interfere with the dishwasher’s ability to clean effectively. Here’s what you can do:

  1. Follow Loading Guidelines: Refer to your dishwasher’s manual for proper loading guidelines. Arrange dishes, utensils, and cookware in a way that allows water and detergent to reach all surfaces.
  2. Avoid Overloading: Overloading the dishwasher can obstruct the spray arms and prevent proper water circulation. Leave enough space between items for thorough cleaning.

5. Detergent Issues

Using the wrong detergent or using too little or too much detergent can impact dishwasher performance. Follow these tips:

  1. Use the Right Detergent: Use a high-quality dishwasher detergent recommended by the dishwasher manufacturer. Avoid using regular dish soap, as it can create excessive suds and affect performance.
  2. Follow Detergent Instructions: Use the appropriate amount of detergent as specified by the manufacturer. Using too little detergent may result in poor cleaning, while using too much can leave residues on dishes.

6. Mechanical Malfunctions

If all the above steps have been checked and the dishwasher still washes poorly or does not wash at all, there may be mechanical malfunctions that require professional repair. Contact a professional technician or the dishwasher manufacturer for further assistance.


You must ensure that your dishwasher has salt and rinse aid in place to prevent limescale build-up and dripping on dishes.

The salt container is in the tank, and the liquid drawer is on the door marked with a striped star.


Detergents or sprinklers, spray the dishwasher with jets of water and rotate at an angle. If nothing prevents them from turning during washing, then you need to check if the holes are clogged.

Simply detach the wash arms and then rinse under water, shaking to remove foreign bodies.


The condenser is used to run the circulation pump. If the pump is not clogged and rotates freely, you should check the capacitor with a multimeter.

The found value must match the one indicated on the coin. After setting the multimeter correctly, place the test leads on the capacitor terminals. If the value found matches that indicated on the label, then the capacitor is good. If not, replace it.


The heating resistor is located at the bottom of the device, resembling a metal cylinder. Just remove the protective sheet with the float against overflow, then check with a multimeter the resistance that allows you to heat the water. It is possible that the circulation pump has a built-in resistor.

Set the multimeter to 600 ohms and put the test leads on the resistor terminals. If OL or 1 is displayed, the resistor is bad and needs to be replaced.


The temperature sensor is used to control the heat of your dishwasher and is located at the bottom of the tank, below the filter. To remove it, it is necessary to remove the receiving plate from the bottom of the device, and then remove the probe using pliers.

First dip the probe into a glass of hot water, then using a multimeter pre-set to 600 kΩ, place the test tips on the probe terminals. If the value changes, then the sensor is working.

Also check that the probe O-ring is not damaged.

Why Does My Dishwasher Wash Badly or No Longer Wash?


The pressure switch allows you to control the pouring of water due to air pressure, but not all dishwashers have them. It is connected to the compression chamber by a hose, usually transparent.

  • Make sure the hose and compression chamber are not clogged with detergent residue. Make sure your hose is clean: nothing should interfere with air circulation. To make sure your hose isn’t punctured, remove it and blow into it while pinching the end. If air comes out, your hose is punctured.
  • To test the pressure switch, remove the air hose and blow inside the pressure switch: you should hear a “click”. If you have to blow very hard, this is a sign of a bad pressure switch.
  • You can also perform a continuity test with a multimeter by placing the multimeter’s probes on the connection terminals of the pressure switch. When you blow, your multimeter should beep.

In conclusion, a dishwasher that washes poorly or no longer washes can be caused by various factors, including clogged spray arms and filters, insufficient water supply, improper loading, detergent issues, or mechanical malfunctions. By following the troubleshooting steps outlined in this article, you can identify and resolve many of these issues. However, if the problem persists or you are uncertain about performing any repairs yourself, it is best to consult a professional technician for further assistance. They will be able to diagnose the underlying cause of the problem and provide the appropriate repair solution, ensuring your dishwasher performs at its best and provides sparkling clean dishes.