Cloudy Spots on Windows That Won't Wipe Off
You cleaned the windows and the cloudy spots are still there. That is because they are not on the glass — they are bonded to it, and left long enough they etch into it.
Where the spotting comes from
Irrigation is the culprit in the overwhelming majority of cases. A sprinkler head throwing onto a window deposits mineral-rich water on the glass; the water evaporates in the Florida sun and the dissolved calcium, magnesium and silica stay behind.
Repeat that several mornings a week and the deposits build into a hard scale layer. The tell is the pattern — a fan or arc of spotting on the lower half of the glass, matching the sprinkler's throw, on the windows nearest the heads.
The other common source is runoff from concrete or stucco above the window, which carries dissolved minerals down onto the glass during heavy rain.
Why it becomes permanent
Fresh mineral deposit sits on the surface and comes off with the right acidic cleaner. This is the easy case, and most spotting we see is still at this stage.
Left for years, the deposit chemically bonds with the silica in the glass and begins to etch it. At that point the glass surface itself is pitted, and no cleaner will restore it — the cloudiness is now part of the pane.
The dividing line is roughly a matter of years rather than months, and it is why we push people to fix the sprinkler rather than schedule repeat cleans.
What not to do
Do not use a razor blade on tempered glass. Much residential glazing is tempered, and scraping it leaves fine permanent scratching that is more visible than the scale.
Do not use abrasive powders or scouring pads. Same outcome — you trade cloudiness for scratching.
Do not keep re-cleaning without fixing the sprinkler. Every cycle of deposit and removal takes the glass a little closer to permanent etching.
What we can do
For deposits that have not yet etched, a mineral-specific cleaner with proper dwell time dissolves the scale and it comes away cleanly. Results on this are excellent.
We assess the glass first and tell you which category you are in. If the pane is etched, we will say so rather than sell you a clean that cannot deliver — restoring etched glass is a polishing job or a replacement, and neither is exterior cleaning.
We will also point out which head is causing it. Turning or capping one sprinkler is usually the entire long-term fix.
Questions we get about this
Can hard water stains always be removed?
How do I know if my glass is etched?
What actually stops it coming back?
Is this included in a normal window clean?
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