There are two causes and they look nearly identical. One washes off. The other is permanent damage to the glass itself and nothing will remove it.
Before buying rinse aid, changing detergent or blaming the dishwasher, find out which one you have. It takes five minutes.
The Test
Take one cloudy glass. Soak it in white vinegar for about five minutes, or hold a vinegar-soaked cloth against the cloudy area for the same time. Then rinse and look.
The film is gone or clearly lighter. That is mineral deposit from hard water. It is sitting on the glass, not in it, and everything in the next section applies.
Nothing changed. That is etching. The glass surface itself has been corroded, and there is no product, no cycle and no service that reverses it. Skip to the etching section, which is about protecting the glasses you have left.
Do this before spending money, because the two problems have opposite fixes and treating etching as hard water makes it worse.
If It Washed Off: Hard Water Deposits
Minerals in the water are being left behind as the water dries. The film builds up over many cycles until it becomes visible, which is why it seems to appear suddenly.
Work through these in order.
Fill the rinse aid. Rinse aid is not a luxury and it is not the same as detergent. It breaks the surface tension so water sheets off the glass instead of sitting in droplets that dry into spots. An empty rinse aid reservoir is the single most common cause of this complaint, and many people have never filled theirs.
Check whether your machine has a salt compartment. Machines sold in hard water regions often include a built-in water softener with a separate compartment for dishwasher salt, which is not table salt and not the same as detergent with "salt action" on the box. If yours has one and it has never been filled, that is your answer.
Clean the filter. A clogged filter recirculates dirty water over clean dishes, and the residue it leaves is easily mistaken for mineral film. This should be routine maintenance anyway and it is covered in how to clean a dishwasher filter.
Run a citric acid or vinegar cycle on the empty machine. The same deposits building on your glasses are building on the machine's interior, the heating element and the spray arms. Blocked spray arm holes reduce rinsing, which makes the film worse, which is a loop worth breaking.
Check your water is hot enough. Detergent works poorly in water that is not hot, and undissolved detergent leaves its own white residue. Running the kitchen faucet hot before starting the cycle helps on machines that do not heat their own water.
Stop overloading. Glasses that touch, or that shield each other from the spray, do not get rinsed. This looks like a chemistry problem and is a loading problem.
Confirm it is actually your water. If you are seeing scale on the kettle, spots on the faucet and film in the shower as well, the dishwasher is not the problem, your water is. The full picture is in signs of hard water in the house, and the same deposits are what descaling a kettle deals with.
If It Did Not Wash Off: Etching
This is the harder conversation. Etching is permanent. The surface of the glass has been chemically corroded, leaving a microscopically rough finish that scatters light and looks cloudy. Nothing puts it back.
It is caused by a combination rather than by one thing:
- Soft water, which is the counterintuitive part. Very soft water is more aggressive toward glass than hard water is.
- Too much detergent, particularly with soft water, where far less is needed.
- High water temperature and long cycles.
- Prolonged exposure, including leaving dishes sitting in the machine for days before running it.
So which problem you have often follows your water. Hard water areas get deposits. Soft water areas get etching. If you have a whole-house softener and cloudy glasses, etching is the likely answer.
What to do going forward:
Use less detergent, especially if your water is soft. The dose on the box assumes average water hardness, and in soft water it is frequently too much.
Use a lower temperature cycle for glassware, or the shorter cycle if your machine has one.
Do not let dishes sit in the machine for days before running it.
Wash the glasses you care about by hand. This is the unglamorous answer and it is the only reliable one. Thin, delicate and older glassware is the most vulnerable, and once you know your machine etches, keeping the good glasses out of it is the fix.
The Third Possibility Worth Ruling Out
If the film is patchy rather than uniform, or if it feels greasy rather than chalky, it may be neither. Redeposited food residue and grease produce a similar-looking haze, and the causes are a dirty filter, a machine that needs a deep clean, or a rinse temperature too low to dissolve fats.
That version usually affects everything in the machine rather than just the glassware, and it responds to cleaning the machine rather than to anything you add to it. Where dishwasher care sits in a wider kitchen routine is in how to deep clean a kitchen.
What Not To Do
Do not scrub etched glass with anything abrasive. It will not remove the etching and it will add scratches.
Do not add more detergent because the glasses look dirty. If it is etching, more detergent is the cause. If it is hard water, rinse aid is what you need, not more detergent.
Do not use vinegar as a permanent additive in the machine. It is fine as a diagnostic and as an occasional empty-machine clean. Regular use over time is not recommended for the rubber seals and internal parts in many machines, and the manufacturer's manual is the authority for yours.
The Short Version
- Vinegar-soak one glass for five minutes. Off means hard water. Still there means etching.
- Hard water deposits: rinse aid first, then salt if your machine takes it, then the filter, then a citric acid clean.
- Etching is permanent. No product fixes it, and it comes from soft water plus too much detergent plus heat.
- Your water tells you which to expect. Hard water leaves deposits, soft water etches.
- Hand wash the glasses you care about if your setup etches. That is the whole solution.
