Hard water stains are the ones that make people think a window is ruined: cloudy white mineral spotting that laughs at every spray in the cupboard and comes straight back through ordinary washing. The good news, from a company that removes them regularly: they are almost always fixable, and the glass underneath is usually perfect.
What They Are
When mineral-rich water dries on glass — from a leaking gutter above the window, a garden sprinkler, or years of rain running off masonry — it leaves its dissolved minerals behind. Layer builds on layer until the deposit is bonded to the surface. That bond is why normal cleaning fails: you are washing the top of the stain, not removing it.
The Method That Works
Our tool for this is fine 0000-grade steel wool, used flat against wet glass. Used correctly, steel wool that fine polishes the deposit off without scratching, because the wool is softer than the glass but harder than the mineral layer. Worked patiently across the pane, it takes the buildup back to nothing — we routinely return stained windows to their original condition on an initial clean.
Two Cautions Before You Try It
First: 0000 grade only. Coarser wool scratches, and a scratch is permanent in a way a stain never was. Second: never on tinted or coated glass — abrasives can damage films and coatings, a subject we cover properly in cleaning tinted and delicate windows. If you are unsure what your glass is, stop and ask someone who does this daily.
Fix the Cause Too
Stains that came from an overflowing gutter will return unless the gutter is sorted — conveniently a thing we also do. Stain removal is part of how we bring neglected properties to standard on a first visit; see what that costs or get your price here.