Mildew is surface mold that you can clean yourself in most cases

Mildew is a thin, powdery or slimy mold that grows on surfaces exposed to moisture and poor air circulation. Unlike deeper mold that penetrates into drywall or wood, mildew sits on top of tile, grout, shower walls, window frames, and fabric. You can remove it with household cleaners and elbow grease—no professional needed unless the affected area is larger than 10 square feet or the mildew keeps returning in the same spot within weeks.

The difference matters because surface mildew responds to scrubbing and bleach-based cleaners, while mold embedded in porous materials often requires removal of the material itself. If you see fuzzy growth, discoloration that spreads despite cleaning, or a musty smell that doesn't fade after you clean, that is likely mold, not mildew, and you should stop and call a professional.

Key Takeaways

  • Mildew lives on the surface of tile, grout, and non-porous materials and responds to bleach, vinegar, or hydrogen peroxide applied with a brush or cloth.
  • Ventilation during and after cleaning prevents mildew spores from spreading, and opening windows or running an exhaust fan is as important as the cleaner itself.
  • Bathroom and kitchen mildew returns quickly if the underlying moisture problem is not fixed—check for leaks, improve ventilation, or reduce humidity before cleaning.
  • Mildew on fabric can be treated with vinegar or commercial mildew spray, but heavily affected clothing or upholstery may need to be discarded.
  • If mildew covers more than 10 square feet, returns within weeks, or you cannot identify whether growth is mildew or mold, contact a mold remediation company.

Cleaning mildew with bleach, vinegar, or hydrogen peroxide

The most common and effective cleaner for mildew is household bleach diluted in water. Mix one part bleach to three parts water in a spray bottle. Spray the affected surface generously, let it sit for 10 to 15 minutes, then scrub with a stiff brush or old toothbrush. Rinse thoroughly with clean water and dry the area completely. Bleach kills mildew spores on contact and prevents regrowth for several weeks on hard surfaces.

If you prefer not to use bleach, white vinegar or hydrogen peroxide work on lighter mildew. Spray undiluted white vinegar directly on the mildew, wait 30 minutes, then scrub and rinse. Hydrogen peroxide (3 percent, the standard drugstore kind) can be sprayed on and left for 10 minutes before scrubbing. Both are less toxic than bleach but also less powerful, so they work better on early-stage mildew or as a preventive spray after you have cleaned with bleach.

For stubborn mildew on grout, make a paste of baking soda and water, explore it to the grout lines, let it dry, then scrub hard with an old toothbrush. Baking soda is gentler than bleach and safe to use around children and pets, though it requires more elbow work. You can also buy commercial mildew removers labeled for bathrooms or kitchens—follow the product instructions exactly, as concentrations vary.

Ventilation and safety while cleaning

Open windows and doors before you start, and keep them open while you clean and for at least 30 minutes after. If you are using bleach, turn on the bathroom exhaust fan or kitchen hood fan and leave it running. Do not mix bleach with ammonia (found in some glass and window cleaners) or with vinegar—both create toxic fumes that can damage your lungs.

Wear rubber gloves to protect your skin, and if you have asthma or respiratory sensitivity, wear a dust mask rated N95 or higher. Mildew spores become airborne when you scrub, so ventilation protects both you and prevents spores from settling elsewhere in your home. If you feel lightheaded, dizzy, or short of breath while cleaning, leave the area when ready and get fresh air.

Removing mildew from bathroom tile and grout

Bathroom tile is one of the most common places mildew appears because showers and tubs create constant moisture. Spray the affected tile and grout with your chosen cleaner (bleach solution works fastest), wait 10 to 15 minutes, then scrub with a grout brush or old toothbrush. Pay special attention to grout lines, where mildew hides in the porous material. Rinse with clean water and dry with a towel or let air dry completely.

After cleaning, the key to preventing mildew's return is reducing moisture. Run your exhaust fan during and for 20 minutes after every shower. Wipe down wet surfaces with a squeegee or towel before you leave the bathroom. If your bathroom has no exhaust fan, open a window during and after showers. If mildew returns in the same spot within two weeks despite good ventilation, there may be a leak behind the tile—stop cleaning and call a plumber to inspect.

Treating mildew on shower curtains and fabric

Mildew on plastic shower curtains can be cleaned in place or removed and washed. For in-place cleaning, spray with a bleach solution, wait 15 minutes, scrub gently with a soft brush, and rinse thoroughly. To wash, remove the curtain and throw it in the washing machine on a warm cycle with one cup of white vinegar and your regular detergent. Do not use bleach in the washing machine with colored curtains, as it will fade them.

For fabric shower curtains, towels, or upholstery with light mildew, spray with undiluted white vinegar, let sit for one hour, then wash in hot water if the fabric allows. If the mildew smell persists after washing, the growth may be too deep in the fibers to remove—in that case, discard the item. Mildew on fabric that has been damp for more than a week is usually permanent and cannot be fully cleaned.

Preventing mildew from returning

Mildew thrives in moisture and poor air circulation. After you clean, focus on the conditions that allowed it to grow. In bathrooms, run the exhaust fan during and after showers, keep the bathroom door open when not in use, and wipe down wet surfaces. In kitchens, use the range hood while cooking, wipe spills when ready, and may support the sink area dries quickly. In basements or crawl spaces, use a dehumidifier to keep humidity below 50 percent.

Check for leaks around windows, under sinks, and around pipes—water intrusion is the most common reason mildew returns to the same spot. If you find a leak, repair it before cleaning the mildew, or the problem will come back. Once a month, spray surfaces prone to mildew (shower walls, window sills, grout) with a preventive solution of one part white vinegar to three parts water. This slows regrowth without requiring heavy scrubbing.

When to call a professional instead of cleaning yourself

Stop cleaning and call a mold remediation company if the mildew or mold covers an area larger than 10 square feet (roughly a 3-by-3-foot square). If you cannot tell whether the growth is surface mildew or deeper mold, err on the side of caution and call—professionals have tools to identify the type and extent of growth. If mildew returns to the same spot within two to three weeks despite good ventilation and cleaning, there is likely a hidden moisture source or structural issue that cleaning alone will not solve.

Also call a professional if you have health concerns, respiratory problems, or a compromised immune system. Mold and mildew spores can trigger asthma, allergies, and infections in vulnerable people, and a professional can assess the risk and handle removal safely. Do not attempt to clean mold in HVAC ducts, inside walls, or in attic spaces—those require professional assessment and remediation.

Frequently Asked Questions

Can I use bleach on colored tile or grout?

Bleach can fade or discolor some tile glazes and grout, especially darker colors. Test bleach on a small, hidden area first. If discoloration occurs, switch to white vinegar or hydrogen peroxide instead. Both work on mildew but take longer and require more scrubbing.

Is mildew dangerous to breathe?

Mildew spores can trigger allergies, asthma, and respiratory irritation in sensitive people, but they are not toxic in the way mold toxins can be. Still, ventilate well while cleaning and avoid prolonged exposure. If you have asthma or mold allergies, wear a mask and consider hiring someone else to clean.

Why does mildew keep coming back in my shower?

Mildew returns when moisture and poor ventilation persist. Run your exhaust fan during and 20 minutes after every shower, wipe surfaces dry, and keep the bathroom door open when not in use. If it still returns within weeks, check for leaks in the walls or plumbing—hidden water is the most common cause.

Can I use a pressure washer to remove mildew?

Pressure washers can remove mildew from outdoor surfaces like decks and siding, but avoid them on bathroom tile or grout indoors—the force can damage grout and force water into walls. For indoor surfaces, stick to brushes and chemical cleaners.

What is the difference between mildew and mold?

Mildew is thin, powdery, and sits on the surface; mold is fuzzy, thick, and penetrates porous materials. Mildew responds to household cleaners; mold often requires professional removal. If you are unsure, assume it is mold and call a professional rather than risk spreading spores.