What Causes Dishes to Turn White After the Dishwasher?

Improper Dish Placement

• You cannot place the dishes in your dishwasher just anywhere and expect the dishwasher to operate effectively. A dishwasher has moving parts, such as the spray arm that rotates on the bottom of the upper rack in some models. If you place tall dishes or even serving pieces of knives in the lower rack, they may stop the spray arm from turning, meaning the dishes are not fully rinsed and so may have soap residue left on them. Placing dishes in the front of the dishwasher, right in front of the soap compartment, may cause a disproportionate amount of soap to coat the dishes directly in front of the dispenser, leaving soap residue. Consult your dishwasher's manual for more information about proper dish placement.

Detergent Problems

• The white substance on your dishes may be dishwasher detergent. If you are not sure, place one of the dishes in vinegar for 10 minutes or longer, and then remove the dish. If the white disappears, the cause is hard water and not the detergent. If you find that the white is from the detergent, try using less detergent per wash. You may also try different brands of detergent, even consulting your dishwasher's manufacturer for recommendations on a brand that works well with your machine.

Hard Water Deposits

• Hard water leaves a white, chalky substance on water faucets, shower doors and anywhere else the water regularly contacts. If your house has a hard water problem, the white you find on your dishes may be from hard water deposits. Installing a home water softener will correct the problem for your whole house's water supply. To solve the problem with your dishwasher alone, use a rinse agent that softens the water in the dishwasher's rinse cycle.

Low Water Pressure

• Low water pressure in your house will affect the operation of your dishwasher, potentially causing the dishwasher to not operate correctly. Your plumbing's water pressure needs to measure between 20 and 120 pounds per square inch, according to home repair expert Don Vandervort, or else the dishwasher cannot clean the dishes properly. Vandervort recommends testing the water pressure in your home by attempting to fill a half gallon jug using your kitchen sink's hot water only, with all other plumbing fixtures switched off. If the jug fills in 14 seconds or less, your house's water pressure is likely sufficient. If you find your water pressure is low, a professional plumber can inspect your plumbing and discuss options with you.