Hard water stains

What It Means

Hard water stains are the pale, crusty marks that form where hard water dries: on shower glass, around faucets, on tile and inside the toilet bowl. The U.S. Geological Survey (USGS) defines water hardness as the amount of dissolved calcium and magnesium in it. When the water evaporates, those minerals stay on the surface. Clorox points out that bleachChlorine bleachHousehold bleach made with sodium hypochlorite that whitens, removes stains and disinfects, but can fade colors and damage some fibers. See more won't lift them; they need an acidic cleaner.

How It Sounds at Home

• "The shower door's all cloudy again."
• "There's that white crust around the faucet."
• "Bleach didn't touch it."

The Breakdown

How to remove them

1. Pick a cleaner made for mineral deposits. Clorox explains that hard water, lime and rust stains need an acidic cleaner, one with a pH below 7, and that bleach isn't effective on them.
2. Read the label for the surfaces it suits and how long it should sit.
3. Apply it and let it work for the time the label gives.
4. Scrub. The American Cleaning Institute (ACI) notes a melamine foamMelamine spongeA cleaning pad of melamine foam, sold as Mr. Clean Magic Eraser and similar, that works like a very fine abrasive when wet. See more pad can scrub hard water stains off tile, tubs and shower doors; test a small spot first.
5. Rinse with water and wipe dry.

Keep them from coming back. The ACI suggests misting a daily shower cleaner on the walls right after a shower, while they're still wet and warm, to keep hard water deposits from building up.

Try it today. Mist the shower walls with a daily shower cleaner right after your next shower, as the ACI suggests.

Good to Know

Acidic cleaners and bleach must never meet. Poison Control warns that an acid mixed with bleach gives off chlorine gas, so never combine them in a bucket, bottle or bowl. Buhata's own suggestion: rinse a surface well with water before switching from one cleaner to another. USGS classes hard water as a nuisance with no health concern. Buhata's own suggestion: ask your water supplier for your hardness figure.

Related Terms and Categories

• Soap scum

  The dull, gray-white film that forms on tubs, tile and shower doors when soap reacts with the calcium in hard water.

• Descaling

  Dissolving the mineral scale that hard water leaves inside kettles, coffee makers and other appliances that heat water.

• Water softener

  A home system that removes the calcium and magnesium that make water hard, usually by trading them for sodium in a tank of resin beads.

• Vinegar cleaning

  Using white vinegar, a mild acetic acid, to dissolve mineral buildup and lift grime. It doesn't replace a registered disinfectant.

• Toilet ring

  A stained line inside a toilet bowl at the water level. A mineral ring from hard water needs an acidic cleaner, since bleach won't lift it.

• Faucet aerator

  The small screened cap on the tip of a faucet spout that shapes the stream and limits how much water flows through.

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