Mildew

What It Means

Mildew is a kind of moldMoldA fungus that grows indoors wherever moisture lingers. EPA says fix the water problem, then scrub it off hard surfaces with detergent and water. See more growth, and Clorox describes mold and mildew as both fungi. It is usually gray or white and shows up on damp things such as shower grout, curtains and fabric that stayed wet. EPA's mold guidance centers on moisture, so drying things out matters as much as cleaning it off.

How It Sounds at Home

• "There's mildew on the bottom of the shower curtain."
• "These towels smell mildewy, they sat in the washer overnight."
• "Crack the window when you shower."

The Breakdown

Bathroom surfaces

1. Turn on the exhaust fan or open a window.
2. Apply a mildew stain remover or a cleaner that contains bleachChlorine bleachHousehold bleach made with sodium hypochlorite that whitens, removes stains and disinfects, but can fade colors and damage some fibers. See more, as the American Cleaning Institute (ACI) suggests, following its label.
3. Leave it on for the time the label gives, then rinse with warm water and wipe dry, as Clorox's bathroom guide does.
4. From now on, leave shower doors and curtains open after use so they air dryLine dryingDrying laundry by hanging it on a clothesline, rack or bar to air dry, indoors or outdoors, instead of using a tumble dryer. See more.

Washable fabric (Clorox)

1. Check the care label first.
2. If the fabric can take chlorine bleach, presoak it in a diluted bleach solution at the strength the bleach label gives, then wash it.
3. For colored fabric, or fabric that can't take chlorine bleach, soak it in a color-safe stain remover such as Clorox 2 for Colors, as that product and the garment label direct, then wash it.

Short version to try today. Run the exhaust fan while you shower, as Clorox suggests, and leave the curtain or door open afterward so the shower dries, as the ACI suggests.

Good to Know

Stopping mildew is mostly about moisture. EPA recommends keeping indoor humidityIndoor humidity levelHow much moisture the air inside a home holds, given as relative humidity. EPA advises keeping it below 60%, ideally between 30% and 50%. See more below 60%, ideally between 30% and 50%, and says damp areas dried within 24 to 48 hours of a leak or spill usually won't grow mold. Chlorine bleach never goes in with another cleaner: Poison Control warns it releases toxic gas with ammonia or with acids such as vinegar. EPA says mold returns if the water problem behind it isn't fixed; the mold page covers EPA's cleanup advice for larger patches.

Related Terms and Categories

• Mold

  A fungus that grows indoors wherever moisture lingers. EPA says fix the water problem, then scrub it off hard surfaces with detergent and water.

• Grout cleaning

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

• Indoor humidity level

  How much moisture the air inside a home holds, given as relative humidity. EPA advises keeping it below 60%, ideally between 30% and 50%.

• Towel washing frequency

  How often to wash towels. Cleveland Clinic advises at least once a week for bath towels, and more often in a humid bathroom or when someone is sick.

• Washing machine cleaning

  Cleaning the inside of a washer, including its drum and door seal, so detergent residue, damp and mildew don't build up. Whirlpool advises about once a month.

• Chlorine bleach

  Household bleach made with sodium hypochlorite that whitens, removes stains and disinfects, but can fade colors and damage some fibers.

Chores, cleaning and home care