Hard Water in Dishwashers

Hard water can be a common issue in households, and it can wreak havoc on our appliances, including dishwashers. When you have hard water, it means your water contains a high concentration of minerals like calcium and magnesium. Over time, these minerals can build up in your dishwasher and leave unsightly stains on your dishes, decrease its efficiency, and even shorten its lifespan. In this blog post, we’ll explore how to test for hard water in dishwashers and some effective ways to address the problem.

Step 1: Assessing Water Hardness

Before you can test for hard water in your dishwasher, it’s essential to know the hardness level of the water in your area. You can find this information by contacting your local water utility or using a water testing kit. Water hardness is typically measured in grains per gallon (GPG) or parts per million (PPM).

  • Soft Water: 0-3.5 GPG or 0-60 PPM
  • Slightly Hard Water: 3.5-7 GPG or 61-120 PPM
  • Moderately Hard Water: 7-10.5 GPG or 121-180 PPM
  • Hard Water: 10.5-14 GPG or 181-250 PPM
  • Very Hard Water: 14+ GPG or 251+ PPM

Step 2: Conducting the Dishwasher Hard Water Test

To determine if hard water is affecting your dishwasher, you can perform a simple yet effective test using citric acid. Citric acid is readily available, safe to use, and works as a chelating agent to remove mineral deposits.

Materials you’ll need:

  • Citric acid powder (easily found in grocery or online stores)
  • A dishwasher-safe container
  • A dishwasher-safe glass or cup
  • Dishwasher detergent

Test procedure:

  1. Ensure your dishwasher is empty and free from any dishes or detergent residue.
  2. Fill the dishwasher-safe container with two cups of water.
  3. Add two tablespoons of citric acid powder to the water in the container.
  4. Place the container on the bottom rack of your dishwasher.
  5. Place the dishwasher-safe glass or cup upright on the top rack.
  6. Run a normal cycle on your dishwasher using hot water but excluding any dishwasher detergent.

Step 3: Analyzing the Results

After the dishwasher cycle is complete, check the glass or cup on the top rack. If your dishwasher is affected by hard water, you may notice one or more of the following signs:

  1. Cloudy Glassware: If the glass appears cloudy or has white spots, it indicates the presence of mineral deposits.
  2. White Residue: Check the container on the bottom rack. If there is a buildup of white residue, it’s a clear sign of hard water affecting your dishwasher.
  3. Poor Cleaning: Dishes not coming out as clean as expected can also be a sign of hard water interfering with the cleaning process.

Step 4: Addressing the Hard Water Issue

If the test reveals that your dishwasher is affected by hard water, there are several ways to address the problem:

  1. Water Softener: Consider installing a water softener for your entire home. This will treat the water before it enters your dishwasher, preventing mineral buildup and other hard water issues throughout your household.
  2. Rinse Aid: Use a rinse aid in your dishwasher to help reduce water spots and residue on your dishes.
  3. Regular Cleaning: Clean your dishwasher regularly to remove any existing mineral deposits. Use a dishwasher cleaner or a vinegar solution to eliminate buildup.


Testing for hard water in dishwashers is a straightforward process that can save you from potential appliance damage and ensure your dishes come out sparkling clean. By assessing water hardness, conducting the citric acid test, and taking appropriate measures to address the issue, you can maintain the efficiency and longevity of your dishwasher while enjoying spotless and sanitary dishwashing results. Remember, prevention is key, so consider investing in a water softener to tackle hard water issues throughout your entire home. Happy dishwashing!

First Choice Appliance team

Hard Water in Dishwashers