Restoration
Cloudy windows almost never mean 'dirty.' Here are the six real causes of hazy and milky glass, how to tell them apart, and which ones are fixable.
August 28, 2026 8 min read
You cleaned the glass. You used the good spray. You wiped until the towel squeaked. And the window still looks cloudy — a milky, foggy haze that shows up the moment afternoon sun hits it at an angle. This is one of the most common calls we get in Los Angeles, and almost every time the homeowner assumes the glass is just dirty. It usually isn't.
Cloudy glass is a symptom, not a diagnosis. There are six distinct causes, and each one looks slightly different up close. Some you can fix yourself in an afternoon. One of them means the window itself has to be replaced. Here's how to tell which you're dealing with.
Los Angeles tap water is hard — very hard. When sprinklers, hose spray, or rain runoff dries on glass, the water evaporates and leaves behind dissolved calcium and magnesium. One cycle is invisible. Two hundred cycles produce a uniform white haze that reads as "cloudy" rather than "spotted."
How to identify it: the haze is worst on the lower third of exterior glass, on the side facing a sprinkler head, and it does not wipe away with glass cleaner. Run a fingernail across it — you'll feel very slight texture, not smooth glass.
The fix: mineral film needs an acidic restoration treatment plus mechanical polishing, not cleaning. Standard glass cleaner is pH-neutral and simply cannot dissolve bonded carbonate. Professional hard water restoration removes it in one visit if the deposits haven't etched yet.
If hard water sits on glass for years, especially in direct sun, the minerals stop sitting on the surface and start eating into it. The result is a permanent cloudiness that survives every treatment. This is the single most important reason not to let mineral haze go untreated.
How to identify it: after a professional restoration, the glass is clean but still slightly foggy in the same pattern. Etched glass also looks worse when wet rather than better.
The fix: light etching can be reduced with cerium oxide polishing. Deep etching cannot be reversed — the pane needs replacing. The good news is that most LA homes we assess are still in the removable-film stage.
Double-pane windows have a sealed air or argon gap. When that seal fails, humid air gets in and condenses on the inside surfaces you can't reach. The haze appears and disappears with temperature, often clearing in the afternoon and returning in the morning.
How to identify it: clean both the interior and exterior surfaces thoroughly. If the cloudiness is still there and you cannot touch it from either side, the seal is gone. A telltale sign is a faint tide-line or rainbow sheen in the middle of the pane.
The fix: no cleaning method reaches between the panes. The insulated glass unit has to be replaced — typically a few hundred dollars per unit, far less than a whole new window. Any window cleaner who says they can clean it is guessing.
Ammonia-heavy sprays, dish soap, and "streak-free" consumer products all leave a surfactant film behind. Each cleaning adds a layer, and after a year the glass has a milky sheen even seconds after being wiped. Paper towels make it worse by shedding lint into the film.
How to identify it: the haze is even across the whole pane, appears on interior glass as much as exterior, and gets slightly worse — never better — after you clean.
The fix: one deep strip-down with a proper detergent solution and a squeegee, then switch to a pure water or professional solution going forward. This is the easiest of the six to solve.
This is the cause almost nobody suspects. Window screens trap years of oxidized aluminum dust, pollen, and road grit. The first time it rains or the sprinklers hit, that grime washes down onto the freshly cleaned glass as a fine gray film. You'll swear the cleaning didn't last a week.
How to identify it: the haze appears in vertical streaks below the screen area, and clean windows go cloudy again within days rather than months.
The fix: have screens removed, washed, and dried whenever the glass is cleaned. It is the single highest-value add-on in window cleaning and it roughly doubles how long your glass stays clear.
Marine fog carries salt aerosol that settles on glass every morning. Salt is hygroscopic — it pulls moisture out of the air — so it never fully dries, producing a soft, slightly sticky haze that dulls glass within weeks of a cleaning.
How to identify it: the haze is heaviest on the ocean-facing elevation, feels faintly tacky, and clears briefly on very dry Santa Ana days.
The fix: quarterly (oceanfront: monthly) cleaning on the windward side. Salt haze is easy to remove but impossible to prevent — the cadence is the whole strategy.
Nine out of ten "cloudy window" calls we take in Los Angeles turn out to be hard water film or dirty screens — both fully fixable in a single visit.
If a normal cleaning doesn't fix it, stop cleaning. Repeated scrubbing on mineral film is how surface deposits become permanent etching, and abrasive pads or razor blades on tempered or Low-E coated glass cause damage that cannot be undone. A proper assessment takes about ten minutes and tells you exactly which of the six causes you have — and whether it's a $100 fix or a glazier call.
Golden View Windows restores hazy and cloudy glass across Los Angeles, from Beverly Hills and Brentwood to Malibu and Santa Monica. We'll tell you honestly if the glass can't be saved — no upsell on a window that needs a glazier.
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