How to Remove Hard Water Stains from Glass Shower Doors

If your shower door has gone from clear to cloudy, the white haze is almost always mineral: calcium and magnesium left behind every time a drop of hard water dries on the glass. Layer on soap scum and a few months of steam, and you get the film that a sprayer and a squeegee can no longer touch. The good news is that on glass, mineral build-up sits on the surface. It can be taken off. The trick is doing it without scratching the glass or breathing something you should not.

Why the usual sprays stop working

Most bathroom cleaners are formulated for soap scum, which is organic. Hard water spots are mineral, and they need either an acid to dissolve them or a mild abrasive to lift them. Vinegar is a weak acid and works on light spots, but on a door that has been building up for a year it is not strong enough, and stronger acids can damage the metal frame, the grout and your lungs in a small bathroom. That is why so many people end up scrubbing with a green pad, which scratches, or giving up and calling a glass company about replacing the door.

What you need

• A jar of A-MAZ Water Stain Remover. It is a paste, not a liquid, so it stays on a vertical door instead of running to the floor, and it contains no bleach, chlorides, acids or gritty pumice.
• A non-scratch pad. The A-MAZ Scrubber Pad or the larger Gripper Pad are both made for glass. Do not use the green side of a kitchen sponge; it is hard plastic and will scratch.
• A spray bottle of water and a dry microfiber cloth.
• A bottle of Ultra Gloss Sealant for the last step.

Step by step

1. Test a corner. Pick an inconspicuous spot at the bottom of the door, apply a small amount of paste with a damp pad, and rub. On clear glass this is a formality, but it is a habit worth keeping for any surface cleaner.
2. Work in sections. Dampen the pad, scoop a little paste, and rub a two-foot section in overlapping circles. Keep the paste moist with a mist from the spray bottle; a dry paste does not cut. You will feel the pad go from dragging to gliding as the mineral lifts.
3. Do the frame and the track. The aluminum frame and the bottom track collect the same deposits. The paste is safe on both, and customers regularly tell us the frame came up as well as the glass.
4. Rinse and dry. Rinse the door with the shower head or a wet cloth and dry it completely with the microfiber cloth. Hold a flashlight at an angle; any remaining haze will show, and a second pass on those spots will take it.
5. Seal it. Put a few drops of Ultra Gloss Sealant on a cloth and rub it over the clean, dry glass until it feels smooth. Two thin coats give full coverage. The sealant fills the microscopic pores in the glass so new minerals have nothing to grip, and on a shower door it lasts about six to nine months.

What if it does not come clean?

If you have rubbed a section twice and the haze is still there when the glass is dry, look at it closely in raking light. If the marks are dull grey and feel slightly rough, the glass may be etched: minerals sitting on glass for years slowly eat into the surface, and no cleaner can put glass back. Most doors are not at that stage, and even etched doors usually look far better after cleaning. If the glass is etched, sealing right away matters even more, because etched glass stains faster than smooth glass.

Keeping it clear

A squeegee after each shower is the single best habit, and it takes fifteen seconds. Reseal when you notice water beginning to sheet instead of bead, usually every six to nine months. If you would rather not think about it, the Shower Restoration Kit has the remover, the sealant and two pads in one box.