Soap scum

What It Means

Soap scum is the cloudy film that builds up on bathtubs, tile, shower doors and sinks. The U.S. Geological Survey (USGS) explains where it comes from: soap reacts with the calcium in hard water, and the product of that reaction is scum. Hard water also takes more soap or detergent to get anything clean, USGS adds.

How It Sounds at Home

• "The tub has that gray film again."
• "Spray the walls before you get out."
• "Leave the curtain open so it dries."

The Breakdown

How to clean it off (American Cleaning Institute)

1. Use a bathroom cleaner labeled for tubs, tile and sinks, and read its directions.
2. Spray the soap film and give the cleaner time to soak into it. Stubborn film needs longer.
3. Rub or scour until the film lifts. The 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 soap scum from tile, tubs and shower doors; test a small spot first.
4. Rinse as the label directs.

Short version to try today. After your next shower, mist the walls with a daily shower cleaner while they're still wet and warm. According to the ACI, this keeps soap scum from building up, and no rinsing or scrubbing is needed.

Why hard water makes it worse. USGS explains that calcium in hard water reacts with soap to form scum, and that hard water takes more soap to get anything clean. The ACI's advice on a daily shower spray names both problems: soap scum and hard water deposits.

Good to Know

Use one bathroom cleaner at a time and follow its label for the surfaces it suits. Keeping the shower door or curtain open after use, as the ACI suggests, lets the walls dry, which also helps keep mildewMildewA flat, usually gray or white mold that grows on damp surfaces such as shower grout, curtains and fabric left wet. See more away.

Related Terms and Categories

• Hard water stains

  White, chalky marks left on glass, faucets, tile and toilets when hard water dries and leaves its calcium and magnesium behind.

• Bathroom deep clean

  A top-to-bottom bathroom cleaning that reaches grout, tub, toilet, floor and fixtures. The ACI's routine puts it every two weeks.

• Grout cleaning

  Scrubbing the lines of grout between tiles with a brush and cleaner to lift dirt, soap film and mildew stains.

• Melamine sponge

  A cleaning pad of melamine foam, sold as Mr. Clean Magic Eraser and similar, that works like a very fine abrasive when wet.

• Mildew

  A flat, usually gray or white mold that grows on damp surfaces such as shower grout, curtains and fabric left wet.

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