Do the vinegar test first, because it splits this problem in two. Soak a cloudy glass in white vinegar for five minutes. If it comes out clear, the film is mineral deposit — fixable with salt, rinse aid and descaling. If it stays cloudy, the glass is etched: microscopic surface damage that is permanent, and the fix is preventing it on the rest of your glassware, not recovering the affected pieces.
The vinegar test
Fill a bowl with white vinegar and submerge one affected glass for five minutes, then rinse and dry it. Vinegar dissolves mineral deposits but has no effect on etching, so the result is a clean diagnosis: clear glass means hard water minerals, still-cloudy glass means the surface itself has been damaged.
If it is mineral film
This is the common case in hard water areas, and it is entirely fixable. The white haze is limescale — the same deposit that builds inside the machine itself, covered in our hard water guide — settling on glassware as the rinse water dries.
- Top up the dishwasher salt
If your machine has a built-in water softener (most European models do), the salt reservoir needs regular refilling — it is separate from detergent, and an empty reservoir is the single most common cause of sudden white film in a hard water area.
- Fill the rinse aid
Rinse aid makes water sheet off glassware rather than drying in droplets that leave mineral rings. Check the dispenser and set its dosage toward the higher end in hard water.
- Run a descaling cycle
An empty hot cycle with a dishwasher descaler or a bowl of white vinegar upright on the top rack clears the machine’s own internal scale, which otherwise redeposits on every load.
- Soak affected glasses in vinegar
The existing film on your glassware comes off the same way the test glass did — a vinegar soak followed by a normal wash.
If it is etching
Etching is the opposite problem: it happens most in soft water with too much detergent, where the wash chemistry is aggressive enough to attack the glass surface itself. The damage is permanent — no cleaning restores an etched glass. What you can do is stop it progressing on the rest of your glassware:
- Reduce the detergent dose, particularly with soft water or a water softener.
- Skip pre-rinsing — detergent with nothing to work on turns its chemistry on the glass instead.
- Use a lower-temperature or glassware programme for delicate items.
- Wash valued or delicate glassware by hand; etching risk never fully disappears in a machine.
Common causes
| Cause | Which problem | How likely |
|---|---|---|
| Dishwasher salt empty | Mineral film | Very common in hard water areas |
| Rinse aid empty or dosed too low | Mineral film | Very common |
| Machine itself scaled up | Mineral film | Common |
| Too much detergent in soft water | Etching | Common |
| Pre-rinsing everything before loading | Etching | Common |
| Very hot cycles on delicate glassware | Etching | Occasional |
Getting consistently clear glasses
Almost every white-film complaint comes down to a mismatch between water hardness and wash chemistry: hard water needs salt and rinse aid topped up; soft water needs less detergent than the packaging suggests. Find out your actual hardness — test strips are cheap, or your utility publishes it — and set the machine up for the water you actually have.
