What Can Cause a Dishwasher to Leave Granules & Scum on Dishes?

Improper Loading

• Something as simple as loading too many dishes into your dishwasher may make the appliance work less efficiently. The result is that the grime on the dishes mostly stays put even though the dishwasher distributes detergent onto them. Since they are so tightly packed into the machine, the dishwasher cannot properly rinse away all of the detergent either. This leaves dishes grainy and dirty.

Water Temperature

• Hot water is what gets dishes clean. It takes high temperatures to properly dissolve dish debris and detergent. The temperature of dishwasher water must reach at least 140 Fahrenheit to clean efficiently. Run the water from your kitchen faucet for 1-to-2 minutes. Measure the temperature with a thermometer. If the temperature does not reach at least 140 Fahrenheit, turn the temperature up on your water heater to make your dishwasher clean properly.

Water Pressure

• Water pressure makes your dishwasher spray away soap and debris at the proper rate. A dishwasher needs water pressure of anywhere from 20-to-120 square pounds per cubic inch inside the dishwasher to turn the spray arms. Determine your home's water pressure by placing a half-gallon jug beneath the kitchen faucet. Turn off all faucets, washing machines and sprinklers and run the water from the faucet into the jug. If the jug fills within 14 seconds, water pressure is high enough, If not, water pressure could be the problems.

Water Hardness

• Hard water is water containing high levels of minerals like calcium and magnesium. When hard water dries, these minerals leave deposits behind on surfaces they touch. Hard water leads to poor dishwasher cleaning by making detergents work less efficiently. Using both detergent cups full of dishwasher detergent along with using a rinse and in the proper cup often helps get dishes clean in even the hardest water.

Internal Clogs

• Hard water does not just make detergents work less efficiently, it also creates clogs in your machine. Over time, sprayer arms and pipes become clogged with hard water deposits, leftover food, detergent and grease creating clogs in the dishwasher. Using a dishwasher cleaning product or running a cycle with no dishes and white vinegar in place of detergent helps maintain the dishwasher and clear out any clogs.