Often, yes, if the marks are only mineral deposits sitting on the glass. A product made for limescale on glass, used carefully after a test patch, can lift them. If the marks have been left for years, the glass may be etched, and then they can be reduced but not fully removed.
What are hard-water marks?
White spots and patches left when hard water dries on glass. Most of Essex has hard tap water, full of dissolved calcium and magnesium. When a drop dries, the water goes and the minerals stay. One drop leaves a faint spot. Repeated wetting in the same place builds those spots into chalky white patches.
Where do they usually come from?
Repeated splashes in one place. The usual culprits are:
- Garden sprinklers or hoses hitting the same panes
- A dripping gutter or overflow pipe above a door or window
- Washing the car or patio near the glass
- Hot tubs and pools next to patio doors
- Washing windows with tap water and letting it dry on
Stopping the source matters as much as the clean. Otherwise the marks come straight back.
Can they be removed?
Usually, if they're fresh. Mineral deposits that sit on the surface can be dissolved. A product made for removing limescale from glass, used as directed, with a soft pad, will lift most of them. It's slow work, and stubborn patches may need several goes.
Always test a small area first, and keep the product off frames, seals and nearby stone or render.
When are the marks permanent?
When the glass is etched. If mineral deposits sit on glass for a long time, especially in sunlight, they can start to roughen the glass surface itself. At that point, you're not cleaning a deposit anymore; the glass has changed. Etching can sometimes be reduced but rarely disappears completely.
A good sign is whether the mark is still there when the glass is wet. If it disappears when wet and reappears when dry, it's likely a deposit. If you can still see it or feel a roughness, it may be etching.
What shouldn't you use?
- Scouring pads and wire wool: they scratch.
- Blades on toughened glass: patio and door glass is usually toughened and scratches easily under a blade.
- Strong acids not made for glass: they can damage frames, seals and surrounding stone.
How do you stop it coming back?
Stop the water reaching the glass, and clean with water that has nothing in it. Re-aim sprinklers, fix dripping gutters and overflows, and don't let tap water dry on the glass. When the windows are cleaned with purified water, nothing is left behind to start new spots.
Can someone remove them for you?
Yes. Our hard-water stain and paint-splash removal starts with a test patch, tells you honestly what's realistic, and then works the whole pane. If the glass is etched, we'll tell you before you pay for something that won't work.