Short answer:
White residue is usually caused by hard water minerals or excess detergent.
Causes of White Film
- Hard water buildup
- Too much detergent
- No rinse aid
How to Fix It
- Use rinse aid
- Reduce detergent amount
- Clean dishwasher monthly
Is It Permanent?
Residue can usually be removed with vinegar soaks. Etching, however, is permanent.