What Causes Soap Scum in a Dishwasher?

Minerals

• Hard water is water that contains a higher than average level of minerals, such as calcium. These minerals are left behind when the water evaporates. The mineral residue can mix with soap residue on the inside of your dishwasher and prevents the soap from rinsing easily. Avoid this by installing a water softener in your home.

Mildew

• Mildew is a variety of fungus that grows in damp conditions. It can easily begin to grow inside your dishwasher, as they are often damp and poorly ventilated. Mildew begins to grow in as little as 24 hours, and it tends to form on dishwashers that aren't used often. Mildew mixes with soap residue and hard water to contribute to your soap scum issue. Prevent it by running your dishwasher more often. The cleaning process flushes out any mildew spores.

Removal

• Remove soap scum due to mineral deposits and mildew by cleaning your dishwasher with white vinegar. White vinegar is a natural cleaning solution that will not damage your dishwasher or pollute your home's air environment. To use it to remove the soap scum, spray it on the inside of the dishwasher and let it soak for several minutes before scrubbing the soap scum off the dishwasher walls. Run the dishwasher as you normally would.

Soap Scum Prevention

• Prevent soap scum from developing in your dishwasher in the first place by adding 1 cup of white vinegar to the bottom of the dishwasher before you run it. The acid in the white vinegar counteracts the alkalinity of the hard water and it prevents soap scum from developing.