Gross, Here’s How to Spot and Stop Mildew Before Your Health Pays the Price

Whether in the form of powdery spots on wood furniture, yellow stains on walls or black gunk in the corners of the shower, most of us have encountered mildew at some point.

Mildew is a type of mold and thrives in moist, damp spaces — clinging to fabric, walls, tiles and wood. It also hides in neglected spots, like the garage, basement, attic, under the sink, behind appliances, a.k.a. any area that traps moisture and has an indoor humidity level outside the normal range (which is between 30% and 50%).

“Besides the ugly black stains it leaves behind, if mildew is left untreated, it can trigger allergies and breathing problems and generally diminishes the indoor air quality in a home,” says Carolyn Forté, executive director of the Good Housekeeping Institute Home Care & Cleaning Lab. While most mildew is visible, you may first detect an outbreak by the musty odor or allergic symptoms like sneezing, itching and difficulty breathing.

It’s ideal to prevent mildew before it starts (tips below), but don’t stress if you’ve already got a mildew situation. Here’s everything you need to know about how to get rid of mildew in every corner of your house.

Expert Tip: When tackling mildew or mold, always wear a face covering, long rubber gloves and protective eyewear.

Mildew vs. mold

Although it’s less dangerous than other types of mold (think black mold), both microscopic fungi can cause health problems and damage to your home. Mildew is typically more visible during early stages and pops up as white or gray powdery dots. It may turn yellow or brown, but generally remains pretty flat. Mold appears darker, often in shades of red, green or black and can have a fuzzy texture. While the mold and mildew can be treated in similar ways, read our tips for removing stubborn mold spots if you suspect a mold outbreak.

How to prevent mildew

• Use a top-tested dehumidifier to keep damp areas, like the basement or bathroom, dry and maintain indoor humidity levels.
• Open the bathroom door during and after showering to allow moisture out.
• Dry or squeegee shower walls, floor and tub after showering to remove excess moisture and help surfaces dry faster.
• If you have bathroom tiles, seal grout lines every year to waterproof the surface.
• Decorate with air-purifying houseplants to help improve air quality.
• Avoid storing linens, books or furniture in damp basements or attics.
• Don’t leave damp towels or gym clothes in bags or closets.
• Track down and fix leaks as soon as possible.

What you’ll need to get rid of mildew

Walls and grout

Mildew can quickly take root on walls and grout, especially in the bathroom where ventilation is poor. It’s important to stop growth during early stages. Here’s how:

1. Mix ¾ cup bleach with one gallon of water (equal to 3 tablespoons bleach to one quart water for smaller areas).
2. Apply mixture with a soft scrub brush for walls or a stiff brush for grout (don’t forget to wear gloves).
3. Let the solution penetrate for 15 minutes before rinsing with water.
4. Wipe dry. Then, use a fan to dry the surface thoroughly.

Shower curtains

If you step into the bathtub and notice that your shower curtain is dotted with mildew, take action quick. Quick prevention tip: Spread out your shower curtain or lining to help it dry.

1. Wash plastic liners or plastic shower curtains in the washing machine on a gentle cycle with the regular amount of detergent — you can also add bleach. Add two to three bath towels for extra cleaning agitation.
2. Hang curtain to dry or put it the dryer on low for a few minutes to remove excess moisture. Stand close by and watch it. Never leave it unattended.

Expert tip: If your shower curtain is fabric or decorative, wash according to the care instructions

Clothing or linens

If you’ve stored clothing or linens in a moist attic or basement, you may notice a mildew scent of mold stains — but don’t worry, here’s how to properly wash away mildew.

1. Use a stiff brush to remove mildew spores (we suggest doing so outdoors).
2. Sun dry the item for about three hours.
3. Check the care labels and if safe, use chlorine bleach or pre-soak colored fabrics for 30 minutes in liquid non-chlorine bleach. For mild stains, you can instead soak the area in equal parts white vinegar and water.
4. Rinse and machine wash as usual.

Washing machines

For front-loading machines, mildew can grow on the rubber gasket if you’re not frequently cleaning your washer.

1. Peel back the rubber gasket, and scrub the area with ¼ cup of chlorine bleach mixed with two cups of water. Use a microfiber cloth or soft-bristled brush.
2. Run a wash cycle on hot with a cup of bleach or a washing machine cleaner, like GH Seal Star Tide Washing Machine Cleaner.
3. Moving forward, regularly clean and dry your washer — paying close attention to the rubber gasket. You should also leave the washer door open after you’ve finished a load, so it’ll dry faster.

Carpets or rugs

Whether you’ve experienced a little flooding or a room is overly damp or humid, mildew may grow on carpets. You may notice a musty smell or greenish stains. Carpets and rugs that are completely saturated by dirty flood water, should be discarded.

1. Make sure the space is dry. Use a wet-dry vacuum to remove water. If possible, hang rugs or carpets outside in the sun to dry. If it’s not possible, open windows and use fans. to air out the space. Try to pick up wet sections if you can to make sure the padding and flooring underneath dry thoroughly.
2. For small stains, use a carpet stain remover. Or, clean and rinse the carpet with a steam cleaner for larger stains.
3. For lingering odors, spray a mixture of one part vinegar and two parts warm water onto the carpet. Allow it to sit overnight. Sprinkle the area with baking soda, and vacuum it up after a few minutes. You may also spray the carpet afterwards with Lysol disinfectant spray, according to label directions to sanitize the surface.

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Wood surfaces

Mildew can grow on wood cabinets, paneling or furniture if they’re exposed to moisture.

1. Vacuum loose spores with the soft brush attachment.
2. Clean small areas using a well-wrung cloth dipped in a few squirts of dishwasher detergent mixed with a gallon of water.
3. Rinse with a clean, water-dampened cloth and dry immediately with a fan. Be careful, not to oversaturate the wood as it could warp or damage the finish.
4. Apply a thin coat of Good Housekeeping Seal holder Weiman Furniture Polish to restore the shine and protect the finish.

Expert tip: After vacuuming mildew spores, toss the filter and bag to prevent spores from escaping into the air next time you vacuum.

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Mattresses (and sofas)

Not only is choosing the best mattress important, cleaning your mattress is critical to your health — and that definitely does not include mildew growth. When cleaning your mattress, you’ll only be cleaning surface stains. Any mattress that’s been damaged by water or may have mildew growing inside should be discarded.

1. Vacuum the entire mattress.
2. For remaining stains, sponge the surface with a cloth moistened in 1 cup rubbing alcohol and 1 cup warm water — but do a spot-test first to make sure the fabric won’t damage.
3. To rinse, wipe the mattress with a water-dampened sponge.
4. Fan dry the mattress for several hours; sprinkle on and brush in baking soda to help remove odors.
5. Spray the surface with a disinfectant, like Lysol, to kill spores that can linger.

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Old books

They might make chic home decor, but old books can be a breeding grown for mildew.

1. Air the pages outside on a sunny, breezy day for at least three hours.
2. Once they’re dry to the touch, brush off the mildew with a dry cloth.
3. Remove stains by wiping the books gently with a soft cloth dipped in a solution of 1 part chlorine bleach to 4 parts water — wring it well first.
4. Wipe the books with a soft cloth dipped in water to gently sponge away the chlorine
5. Pat or fan dry. Speed up the drying process by sprinkling cornstarch or baking soda on each page to absorb any remaining moisture, then wipe it off with a soft, clean paint brush.

Senior Editor

Lauren is a senior editor at Hearst. She was previously the senior editor at WomansDay.com and the home editor at GoodHousekeeping.com and HouseBeautiful.com. Her book club, ramen, and jean jackets are a few of her favorite things.

Associate Lifestyle Editor

Alyssa Gautieri (she/her) is the associate lifestyle editor for Good Housekeeping, where she covers all things home and interior design. Prior to joining GH in 2022, she wrote for publications including ELLE Decor, Chairish, BobVila.com, Unique Homes Magazine and LODGING Magazine, in addition to crafting product copy for home brands like BrylaneHome and VIGO Industries.