Mold vs Mildew: The Real Difference
Mold vs mildew is a question about words more than biology, because home guides agree that mildew is a type of mold. Mildew usually describes flat, white or gray growth on a surface, and mold usually describes raised, fuzzy or darker growth that has gone deeper. The EPA and CDC pages use only the word mold, so the practical rule for a homeowner is how much there is and what it sits on.
Mold vs mildew: how they look different
Bob Vila and This Old House describe mildew as flat and powdery, usually white or gray, and mold as raised or fuzzy and often green or black. Mildew tends to sit on a surface such as shower grout or a window sill and wipes off. Mold that has grown into drywall, wood or carpet does not wipe off.
What the government sources say
No government or medical source read for this guide defines mildew apart from mold. The EPA brief guide and the CDC mold page use only the word mold. Health claims on commercial pages, such as mold affecting the nervous system, carry no citation there and are not repeated here.
Does the difference change what you do
Not much. For a small surface patch the EPA advises detergent and water and a full dry, for either word. Bigger growth, growth inside a wall, and growth that returns are crew jobs. The CDC adds that you do not need to know the type of mold before removing it.
Keep both from coming back
The EPA says the key to mold control is moisture control, and it gives 60 percent as the indoor humidity ceiling, with 30 to 50 percent ideal. Dry water-damaged items within 24 to 48 hours, run bathroom fans during and after showers and fix leaks quickly. Los Angeles averages about 71 percent humidity at LAX, so coastal homes need the fan more than the forecast suggests.
Mold vs mildew: questions answered
Is mildew a type of mold?
Yes, per the home guides read. Mildew is the common name for certain flat surface growth, and no health agency page read for this guide uses it as a separate term.
Is mildew less dangerous than mold?
The sources do not say so. The commercial guides make health claims without citing a health agency, and the CDC warns that people with asthma or mold allergy may react to any mold.
Can I clean mildew in my shower myself?
Yes, on a small hard surface. Use detergent and water, dry it completely and run the fan, and call a crew if it keeps returning or the wall behind it is soft.