|appliance resource center|
dishwasher troubleshooting: dishwasher leaves white film on glasses
That white film could be caused by pre-washing or rinsing your dishes before you put them in the dishwasher.
Many of today’s dishwasher detergents contain phosphates, which need food residue to break down. So, if there’s no food residue or grease, the phosphates don’t break down. Instead, they somehow end up on your glassware.
As if you need another reason to stop pre-rinsing/washing your dishes.
So, washing my dishes actually causes them to become dirty. If you find yourself with a rack of filmy glassware, save the labor — and the water (rinsing dishes often uses more water than a dishwasher cycle) — and run a warm vinegar rinse.
Put 2 cups white vinegar in a glass or dishwasher-safe measuring cup on the bottom rack. Then run the dishwasher through a complete washing cycle using an air-dry or an energy-saving dry option. Do not use detergent. The vinegar will mix with the wash water.
Running a vinegar cycle every few months is a good idea, per se.