Why is my dishwasher leaving residue on dishes?

Residue on dishes is often due to improper loading, using too much or too little detergent, or hard water. Make sure dishes don’t block the spray arms and avoid overcrowding. Use a detergent suited for your water type, and add rinse aid to reduce spotting. Check that the water temperature reaches at least 120°F for effective cleaning. Clean the dishwasher filter and spray arms regularly to prevent clogs. If your area has hard water, consider installing a water softener or using a detergent with water-softening agents.