What’s the Difference Between Mold and Mildew?

(Last Updated On: June 25, 2019)

What's the Difference Between Mold and Mildew?

Just like possums and opossums, people like to use the terms “mold” (not to be mistaken for slime molds) and “mildew” interchangeably. If you’ve taken the Google plunge to find the difference, you’ve already completed the first step; they are a little different. But they’re also pretty similar too. They’re both fungus and grow in similar conditions (damp places with relatively low air filtration), reproducing through spores. In fact, mildew is a type of mold. That still doesn’t mean they’re the same though. So what’s the deal with mold and mildew?

What’s the Difference Between Mold and Mildew?

In this post, we’ll be looking at mold and mildew in respect to your home, as that is the place most people probably encounter them (and now probably is not a bad time to check your sink or shower). If you do ever find mold or mildew in your home, there’s a 50% chance that you’re in luck. That’s because mildew is easy to take care of, where as mold has the potential to be dangerous.

Mold spores can induce chronic coughing and sneezing, as well as nasal congestion. Your skin may be dry, your eyes may itch or water, heck, you may even straight up have problems breathing. While mildew spores can induce similar effects, mold is far more dangerous–to the point where mold infestations may require you to hire someone else to clean it out.

Mildew is less notorious for its effects on your body. It’s more infamous for being a general nuisance. It kills crops and other plants, so you can imagine how a gardener or a farmer wouldn’t like this freeloading fungus. But if you’ve got mildew in your home, you’re luckier than mold. However, don’t completely write off mildew. It can cause similar health issues to mold if you’re unlucky. Mildew generally makes things look ugly, but it’s not eating away at wood or plaster like mold does. Just because it’s cosmetic doesn’t mean you can let it sit though. Be hygienic and clean your fungi. As for mold, mold decomposes things in nature (ergo, helps things rot back into nothing for reuse). As we just implied, yes, mold is decomposing your house if it’s around.

How Can I Tell the Difference?

It’s not too difficult to tell the difference between mold and mildew. Mildew tends to take on a powdery appearance, while mold looks fuzzy (if you’ve ever seen a fruit mold over, think of that). Mold may be black, red, brown, yellow, white, or really a large variety of colors. You’ll normally find mold growing in irregular spots. If you’re smelling mold, it’s generally described as musty (but not always with some foul odor). Mildew still smells musty though, so basically if your air is musty it’s time to go hunting for fungus. Maybe consider getting some air cleaning done too. Mildew grows white, but eventually can turn yellow, brown, or black. It, as we mentioned, looks powdery, tending to grow flat (as opposed to being spotty).

According to some sources, you can use household bleach as an okay DIY indicator. If the fungal patch turns white after you drop a little bleach, you have a mildew problem. If it stays/turns dark, you got a mold issue.

Mildew is pretty easy to clear up, and small mold issues can be rectified similarly too. The former grows on surfaces, so you generally can just scrub it out. Mold is far more frustrating, since it’s a decomposer. It’s got microfibers digging into whatever it sits on, so you’re gonna have to root it out with more intense cleaners–or just get a professional.

Mold vs. Mildew

Mold Mildew
Fuzzy or Slimy Powdery
Black, Brown, Yellow, Red, Green, Blue, etc. White, Black, Brown, or Yellow
Grows in irregular patches Grows with a flat appearance
Roots into whatever it’s on, removing it is harder Grows on the surface (so you can scrub it out)
Musty smell Musty smell
Can pose serious health risks Poses more risks to other plants than to you
Literally decomposes your home Only causes cosmetic damage
If you don’t clean it you’ll probably get sick If you don’t clean it you might not get sick

It’s not about mold or mildew, but consider testing your fungal finding skills here.



About Kyler 687 Articles
Kyler is a content writer at Sporcle living in Seattle, and is currently studying at the University of Washington School of Law. He's been writing for Sporcle since 2019; sometimes the blog is an excellent platform to answer random personal questions he has about the world. Most of his free time is spent drinking black coffee like water.