Mold vs Mildew: How to Tell Them Apart and Clean Each

The EPA explains that the word "mildew" refers to certain kinds of mold or fungus, and that the term is often used loosely for mold growth with a flat growth habit. Molds, more broadly, include all species of microscopic fungi that grow in the form of multicellular filaments, called hyphae.

The University of Florida's extension service puts it plainly: mildew is a mold that can grow and cause damage to your health and home. So when someone says "mildew vs mold," they usually mean light surface growth versus heavier, deeper growth.

There is no lab-free test that tells you for sure, and descriptions vary from source to source. Here are the general signs.

Table: mold vs mildew comparison. Sources linked in each cell.

Notice that the sources don't fully agree. Bob Vila describes mildew as white or gray and powdery, while UF Extension describes mildew as black, brownish, or reddish fuzzy discoloration. That's because "mildew" is a loose everyday word, not a strict scientific category. Color is not a reliable way to tell them apart.

A practical way to decide

Instead of trying to name it, ask three questions:

1. What is it growing on? Hard, non-porous surfaces like tile, glass, sealed grout and metal can be cleaned. TDLR lists concrete, metal, glass, tile, and solid wood as non-porous surfaces where mold can be cleaned.
2. Does it come back right after cleaning? Growth that returns quickly in the same spot usually means moisture behind or under the surface.
3. How big is it? The EPA's homeowner line is about 10 square feet.

You also don't need a lab to identify it. The CDC says you do not need to know the type of mold; remove it either way. The EPA adds that in most cases, if visible mold growth is present, sampling is unnecessary.

Mildew mold removal on hard surfaces is a normal cleaning job.

1. Ventilate. Open a window or run the exhaust fan.
2. Protect yourself. For small cleanups, the EPA's minimum gear is gloves, an N-95 respirator, and goggles/eye protection.
3. Scrub with detergent and water. The EPA's instruction for hard surfaces is to scrub mold off hard surfaces with detergent and water, and dry completely. Bob Vila notes that standard household cleaning products and a scrubbing brush work on mildew.
4. Or use vinegar or diluted bleach, never both. Oregon State University Extension suggests a half-water, half-vinegar solution. If you use bleach, the CDC says no more than 1 cup of household laundry bleach in 1 gallon of water, and UF Extension says to open the window for ventilation and not mix bleach with any other cleaning product.
5. Dry the surface completely.

Never mix bleach with ammonia or vinegar. The CDC says mixing bleach with ammonia or other cleaners will produce a poisonous gas. Details are in our vinegar vs bleach for mold guide.

Mildew on clothes and fabric

UF Extension gives specific steps for fabrics:

• For mildew-stained clothes, mix 2 tablespoons of liquid chlorine bleach with 1 quart of water, sponge or soak for 5 to 15 minutes, then rinse.
• For a full washer load, add 1 cup of chlorine bleach in the wash water.
• For fabrics bleach would damage, use non-chlorine bleach and soak for 30 minutes or longer, then rinse.
• For musty bedding, put it in the sun for several hours; if mildew remains, sponge with 1 cup of rubbing alcohol and 1 cup of water, then dry thoroughly.

Always check the care label first.

When growth is raised, spreading, or in a porous material, a surface wipe isn't enough.

• Porous materials: The EPA says absorbent or porous materials, such as ceiling tiles and carpet, may have to be thrown away if they become moldy. TDLR says mold is difficult to clean from absorbent (porous) surfaces such as drywall, carpet, fleecy furnishings and insulation, so those materials should be removed and discarded.
• Don't cover it up. The EPA says do not paint or caulk moldy surfaces.
• Bleach won't save drywall. TDLR says applying bleach to drywall without removing the mold source is not a permanent effective solution.

For walls specifically, see mold on walls and drywall. For bathrooms, see mold in the shower.

The fix for both is the same: control moisture. The EPA says the key to mold control is moisture control.

• Keep humidity down. The EPA recommends keeping indoor humidity below 60 percent (ideally between 30 and 50 percent). A dehumidifier helps; see our dehumidifier for mold guide.
• Vent the bathroom. The EPA says to run the bathroom fan or open the window when showering.
• Dry the shower. UF Extension suggests you dry/squeegee off the shower walls after using the shower and hang damp towels where air circulates.
• Don't leave wet laundry sitting. UF Extension says to make sure clothes are dry before putting them in the hamper.
• Dry leaks fast. The EPA says to dry water-damaged areas and items within 24-48 hours.

UF Extension notes that mildew grows best in moist, warm air. Much of Texas fits that description, especially the eastern half, where NOAA says the Gulf serves as the primary source of moisture.

Closets, shoes and furniture

Mildew isn't only a bathroom problem. The EPA says molds can grow on clothing, paper and building surfaces affected by moisture. UF Extension's prevention list covers the spots people forget:

• Closets. Open closet doors so air will circulate, and don't hang sweaty clothes back up.
• Shoes. UF says to keep shoes dry and clean.
• Furniture. Remove food stains from furniture as quickly as possible.
• Air movement. Use ventilation fans to draw moist air out of the home and ceiling fans to circulate the air.

If you find mildew on a closet wall rather than just on clothes, check that wall for a leak or condensation. The EPA says condensation can come from high humidity or cold spots in a building, and outside walls behind closet clutter are a likely cold spot. Our mold on walls guide covers what to do next.

The EPA says that if the moldy area is less than about 10 square feet (less than roughly a 3 ft. by 3 ft. patch), you can usually handle it yourself. If there's a lot of water damage or growth covers more than 10 square feet, the EPA points to its professional remediation guidance. It also suggests hiring an experienced professional if you believe you have a hidden mold problem.

In Texas, TDLR says that in most instances, areas of visible mold less than 25 contiguous square feet may be cleaned by people who aren't licensed. For larger jobs, use a licensed mold removal company. If you need an assessment first, hire a separate mold testing company; Texas law says a license holder may not perform both mold assessment and mold remediation on the same project. You can check any license with our license check, and find companies across Texas, including San Antonio.