Hard water stains: why your glass never looks clean
5 min read · February 20, 2026
Mineral scale needs acid and dwell time, not force. How to remove it and how to stop it coming back.
That cloudy film on shower glass and the white crust on faucets isn't dirt — it's calcium and magnesium left behind when water evaporates. Scrubbing harder just scratches the surface it's sitting on.
Dissolve, don't scrub
Use a citric-acid or commercial descaler, apply it wet, and let it dwell 10–15 minutes so the acid has time to work. Then wipe with a non-scratch pad. On badly built-up glass you may need two cycles — that is normal and still far safer than abrasives.
Know where acid is banned
Never use acidic descalers on marble, travertine, limestone or unsealed grout — they will etch. For stone, use a pH-neutral stone cleaner and accept slower progress.
Prevention is 30 seconds a day
A squeegee after each shower removes the water before it can evaporate and deposit minerals. Dry faucets with the towel you already used. Over a year that habit saves hours of restoration work.
Acid plus dwell time removes scale; a daily squeegee stops it returning.