Why Does My Dishwasher Leave White Marks on the Dishes?

Jul 19, 2023, 17:20pm

If you have a problem with white marks on your dishwasher or it no longer washes as well, the appliance’s electronic board may be at fault. This is the element that processes the electronic programming of the machine and coordinates the washing cycle according to the program chosen by its user. The problem can also come from the salt box and the softener:

  • The salt allows the resins contained in the internal softener to be regenerated, in order to guarantee effective elimination of the limestone present in the water.
  • The softener must be adjusted according to the hardness of the water, i.e. whether it contains a lot or a little lime.

If you have the impression that your dishwasher does not wash more or less well, there will be several elements to see:

  • Check the salt pot
  • Check the dosage
  • Adjust the water hardness
  • Check regeneration valve

This can solve your problem of white mark(s) on your dishwasher.

Discovering white marks or spots on your freshly washed dishes can be frustrating, especially when you rely on your dishwasher to provide spotless results. These white marks are often caused by mineral deposits or residue left behind during the wash cycle. Understanding the common causes of this issue can help you address and prevent it. In this article, we will explore the possible reasons why your dishwasher leaves white marks on the dishes and provide guidance on how to resolve the problem.

Why Does My Dishwasher Leave White Marks on the Dishes?

1. Hard Water

One of the most common causes of white marks on dishes is hard water. Hard water contains high levels of minerals such as calcium and magnesium, which can leave behind deposits on surfaces. Here’s what you can do:

  1. Check Water Hardness: Determine the hardness of your water by contacting your local water utility or using a water testing kit. Hardness is typically measured in grains per gallon (gpg) or parts per million (ppm).
  2. Use a Water Softener: Consider installing a water softener or using a dishwasher additive specifically designed to combat hard water. These products can help reduce mineral deposits and prevent white marks on your dishes.

2. Insufficient Rinse Aid

Rinse aid plays a crucial role in the drying process of your dishwasher. It helps water sheets off the dishes, reducing the formation of water droplets that can leave behind white marks. Follow these steps:

  1. Check Rinse Aid Level: Ensure that your dishwasher has an adequate amount of rinse aid. Consult your dishwasher’s manual to locate the rinse aid dispenser and refill it if needed.
  2. Adjust Rinse Aid Setting: Some dishwashers allow you to adjust the rinse aid dosage. Experiment with different settings to find the optimal amount for your dishwasher and water hardness level.

3. Detergent Residue

Excessive detergent usage or improper detergent selection can contribute to white marks on dishes. Here’s what you can do:

  1. Use the Right Detergent: Make sure you’re using a high-quality dishwasher detergent that is specifically designed for your dishwasher. Consult your dishwasher’s manual or contact the manufacturer for recommended detergents.
  2. Follow Detergent Guidelines: Avoid using too much detergent as it can result in excess residue. Follow the manufacturer’s instructions regarding the appropriate amount of detergent to use for your dishwasher and water hardness level.

4. Loading and Dish Placement

Improper loading or overcrowding of dishes can prevent proper water circulation and result in white marks. Consider these tips:

  1. Load Dishes Properly: Arrange dishes in a way that allows proper water flow and prevents them from blocking the spray arms. Avoid overcrowding the dishwasher, as it can impede water circulation.
  2. Separate Silverware: Ensure that silverware is properly spaced and not nested together, as this can lead to white marks caused by silverware rubbing against each other.

5. Clogged Spray Arms or Filters

Clogged spray arms or filters can restrict water flow and cause inadequate rinsing, resulting in white marks on dishes. Here’s what you can do:

  1. Clean the Spray Arms: Remove the spray arms and clean them thoroughly. Use a toothpick or a small brush to clear any debris or mineral deposits from the spray arm nozzles.
  2. Clean the Filters: Remove the dishwasher filters and clean them according to the manufacturer’s instructions. Regularly cleaning the filters helps maintain proper water flow and prevents residue buildup.

Why Does My Dishwasher Leave White Marks on the Dishes?


With each wash, the regeneration valve opens and forces water through the salt tank before it enters the softener. This valve is located at the level of the softener, at the bottom rear of the dishwasher, behind the plinth.

  • Disconnect its connector, then measure its value with a multimeter: the valve coil should have a resistance of 2 to 5 kOhm.
  • If you find 1 or OL, this means the valve has sheared and needs to be replaced.

If the valve is OK, the softener must be replaced.

In conclusion, white marks on dishes from the dishwasher can be caused by hard water, insufficient rinse aid, detergent residue, loading and dish placement issues, or clogged spray arms and filters. By following the tips outlined in this article, you can minimize and prevent white marks on your dishes. If the problem persists or you are uncertain about performing any repairs yourself, it is best to consult a professional technician or contact the dishwasher manufacturer for further assistance. They will be able to diagnose the underlying cause and provide appropriate guidance to ensure your dishes come out spotless after every wash.