Mildew is surface mold that you can clean yourself with the right approach
Mildew is a thin, powdery or slimy mold that grows on surfaces in damp areas. Unlike deeper mold that roots into materials, mildew sits on top of tile, grout, shower walls, window sills, and fabric. You can remove it with household cleaners and elbow grease—no professional needed in most cases. The key is catching it early, cleaning thoroughly, and then stopping moisture from bringing it back.
Mildew thrives where humidity stays high and air does not move. Bathrooms, basements, and poorly ventilated closets are common spots. It does not mean your home is dirty; it means water is lingering where it should not. Once you clean it, the real work is drying out the space so it does not return within weeks.
Key Takeaways
- Mildew can be removed with white vinegar, hydrogen peroxide, or commercial mildew cleaners applied directly to the surface and scrubbed.
- Always ventilate the area while cleaning and wear gloves and eye protection to avoid skin and eye irritation.
- After cleaning, dry the surface completely and run a fan or dehumidifier to lower humidity so mildew does not return within days.
- If mildew covers more than 10 square feet, grows back repeatedly in the same spot, or you have respiratory concerns, contact a mold professional.
- Preventing mildew means keeping bathroom and basement humidity below 50 percent and wiping down wet surfaces after showers or spills.
What you need to clean mildew safely
Gather your supplies before you start. You will need gloves (nitrile or rubber), eye protection, and a cloth or soft brush. For the cleaner itself, you have three main options: white vinegar (5 percent acidity), hydrogen peroxide (3 percent from the drugstore), or a commercial mildew remover. All three work on surface mildew; choose based on what you have on hand and how strong a smell you can tolerate.
Vinegar is the gentlest and smells like salad dressing. Hydrogen peroxide is stronger and leaves no smell. Commercial cleaners like Tilex or Clorox Mildew Remover work fastest but contain harsher chemicals. Never mix cleaners—especially bleach with ammonia or vinegar, which creates toxic gas. If you are cleaning fabric like a shower curtain or bathroom mat, check the label first; some fabrics bleach or weaken with strong cleaners.
Open windows or turn on the bathroom exhaust fan before you begin. Mildew spores become airborne when disturbed, and ventilation carries them out instead of letting them settle elsewhere in your home.
Step-by-step cleaning for tile, grout, and hard surfaces
Spray or explore your chosen cleaner directly onto the mildewed area. Let it sit for 10 to 15 minutes—this gives the cleaner time to break down the mildew without you having to scrub as hard. Do not let it dry completely; you want it still damp when you scrub.
Use a soft brush, old toothbrush, or cloth to scrub in circular motions. For grout lines, a grout brush or an old toothbrush works best because the bristles fit into the narrow spaces. Rinse thoroughly with clean water and dry with a towel or let air dry completely. If mildew remains, repeat the process—stubborn spots sometimes need two applications.
For shower walls and tub surrounds, pay special attention to corners and the base of the tub where water pools. These spots dry slowest and are where mildew returns first. After cleaning, squeegee the shower walls after each use to remove standing water.
Cleaning mildew on fabric and porous surfaces
Shower curtains, bath mats, and caulk are trickier because the mildew can penetrate slightly into the material. For a plastic shower curtain, spray with vinegar or hydrogen peroxide, let sit 15 minutes, scrub gently, and rinse well. If the mildew is heavy or the curtain is old, replacing it is often faster and cheaper than fighting it.
Bath mats and towels can go in the washing machine with hot water and a cup of white vinegar or a commercial mildew treatment. Dry them completely in a dryer or in direct sunlight—sunlight naturally kills mildew spores. Do not leave damp towels in a pile or closed hamper, which creates the exact humid environment mildew loves.
Caulk around tubs and sinks is harder to clean because mildew grows inside the porous material. If the caulk is discolored but not thick with growth, try scrubbing with a toothbrush and vinegar. If mildew keeps returning to the same caulk line within a few weeks, the caulk itself is compromised and should be removed and replaced—a 30-minute job with a caulk removal tool and fresh silicone caulk.
Drying out the space so mildew does not return
Cleaning mildew is only half the job. If you do not lower the humidity, mildew will be back in a week or two. After cleaning, run the bathroom exhaust fan for at least 30 minutes after every shower. If you do not have an exhaust fan, open a window and run a portable fan to move air out.
Check your home's humidity with an inexpensive humidity meter (under $15 at hardware stores). Mildew thrives above 60 percent humidity; aim for below 50 percent. In basements or bathrooms that stay damp, a small dehumidifier removes moisture from the air and prevents mildew from growing back. Empty the dehumidifier's tank daily or run a drain hose to a floor drain.
Wipe down shower walls and the tub rim with a dry cloth after each shower. This removes standing water that would otherwise evaporate slowly and feed mildew. In winter, when you are heating your home, humidity often drops naturally—mildew is less common then. In summer or in damp climates, dehumidifiers earn their cost by preventing repeated cleaning.
When to stop cleaning and call a professional
If mildew covers an area larger than 10 square feet, or if it grows back in the same spot within a few weeks despite your cleaning and drying efforts, something deeper is wrong. Mildew that returns quickly usually means water is getting behind the surface—a slow leak in a wall, a crack in the foundation, or a plumbing issue you cannot see. A mold professional can identify the source and recommend repairs.
Also call a professional if you have asthma, allergies, or a weakened immune system and mildew is visible in your home. Even surface mildew releases spores that can trigger symptoms. If you are pregnant or caring for an infant, the same caution applies. A professional can clean more thoroughly and help you understand whether the mildew is a one-time event or a sign of a moisture problem that needs fixing.
Preventing mildew from starting in the first place
The easiest mildew to clean is the mildew you never grow. Keep bathroom humidity low by running the exhaust fan during and for 30 minutes after showers. Wipe down wet surfaces, especially around the tub and sink. Hang towels to dry fully before putting them in the hamper—a damp towel in a closed space is a mildew factory.
In basements, use a dehumidifier year-round if the space stays below 50 percent humidity naturally only part of the year. Fix leaks promptly; a small drip that you ignore for weeks will create mildew and eventually rot wood or drywall. may support gutters are clean and downspouts drain at least 4 feet away from the foundation so water does not pool against the house.
In closets and under sinks, leave space for air to circulate. Do not pack items tightly or store them directly on the floor. Use shelf liners that allow air to move underneath. In very humid climates, small moisture-absorbing packets or a rod-mounted dehumidifier in a closet can prevent mildew from starting on stored clothes.
Frequently Asked Questions
Is mildew the same as mold?
Mildew is a type of mold, but it is thinner and stays on the surface. Mold can be thicker, darker, and roots into materials. If what you are seeing is fuzzy, thick, black, or green and does not wipe away easily, it may be mold rather than mildew, and you should contact a professional before cleaning.
Can I use bleach to clean mildew?
Bleach kills mildew but is harsh on skin and lungs. If you use it, dilute one part bleach to ten parts water, ventilate very well, and wear gloves and eye protection. Never mix bleach with ammonia or vinegar. Vinegar or hydrogen peroxide work just as well and are safer to use in a small bathroom.
Why does mildew come back so fast?
Mildew returns quickly when humidity stays high or water sits on surfaces. After cleaning, focus on drying the area completely and keeping humidity below 50 percent. If it returns within a few weeks despite your efforts, the moisture source may be a leak or poor ventilation that needs professional attention.
Can I prevent mildew on a shower curtain?
Yes. After each shower, spread the curtain open so it dries fully instead of bunching up wet. Wash it monthly in hot water with vinegar. Replace it every 6 to 12 months—a new curtain costs less than fighting mildew repeatedly. Fabric shower curtain liners can be washed; plastic ones are cheaper to replace.
Is mildew in my basement a sign of a serious problem?
Basement mildew usually means humidity is too high or water is seeping in. Run a dehumidifier and check for cracks in the foundation, wet spots on walls, or standing water. If the mildew is widespread or returns quickly, have a basement specialist inspect for leaks or drainage issues before they cause structural damage.