Black Mold vs. Mildew: How to Tell the Difference

You’ve spotted something suspicious growing in your bathroom, basement, or kitchen. It’s dark, maybe a little fuzzy, and you’re not sure whether to panic or grab a sponge. Learning how to identify black mold vs. mildew is an important step toward protecting your home and your family’s health. 

Both mold and mildew are types of fungi that thrive in damp environments. They differ in important ways, including the risks they pose. This guide will help you tell the difference between black mold and mildew, understand what you’re dealing with, and know when you should contact a professional for mold remediation.  

Key Takeaways

• Mold and mildew are both fungi that thrive in moist environments, but they have different appearances, growth patterns, and health risks. 
• When comparing mold vs. mildew, mold is typically darker, penetrates surfaces, and poses more serious health concerns; mildew tends to stay on the surface and is easier to clean. 
• Black mold can appear slimy or fuzzy and is usually greenish-black, whereas mildew usually looks flat, powdery, and white or gray. 
• You can often get rid of small mildew patches with DIY cleaning, but large areas of black mold usually require professional remediation. 
• Controlling moisture is the most effective way to prevent both mold and mildew from taking hold.  

At a Glance: Mold vs. Mildew

What Is Mold? 

Mold is a fungus that plays an important role in breaking down organic matter in nature. But it can be a real pain when it shows up in your home. Mold loves humid, wet environments, and when mold spores land in this type of place (like your bathroom or a leaky faucet under the kitchen sink), they can begin growing within 24 to 48 hours. 

There are thousands of mold species, but the most common types found in homes include Aspergillus, Penicillium, Cladosporium, and Stachybotrys chartarum (commonly known as black mold).  

You should remove any mold you find in your house, but black mold is particularly dangerous due to the mycotoxins it can produce. If you inhale a lot of them over time, they can trigger respiratory issues. Young kids, seniors, and anyone with a compromised immune system are especially vulnerable. If you’re not sure what type of mold you’re dealing with, it’s best to contact a remediation specialist to evaluate the situation. 

Where You Might Find Mold

• Basements and crawl spaces 
• Bathrooms and kitchens 
• Around leaking pipes or appliances 
• Behind walls with water damage 
• Inside HVAC systems and air ducts 
• Under flooring or carpeting 

What Mold Looks Like

• Fuzzy or slimy in texture 
• Black, dark green, brown, gray, or orange in color 
• Appears in irregular, spreading patches 

Mold Exposure Symptoms

• Sneezing and coughing 
• Nasal congestion 
• Eye irritation 
• Skin rashes 
• Sore throat 
• Respiratory issues   

What Is Mildew?

Mildew’s also a fungus, but it behaves differently from mold. It tends to grow on top of surfaces, making it easier to spot and clean. Like mold, it also loves warm, humid places. 

Though mildew is generally less harmful than mold, that doesn’t mean you should ignore it. Left untreated, mildew can emit unpleasant odors, damage valuable materials, like your favorite sweater, and cause mild respiratory irritation. It can also serve as an early warning sign of excess moisture in your home, which can invite mold growth. 

Where You Might Find Mildew

• Bathroom tiles and shower curtains 
• Windowsills and window frames 
• Damp fabrics and clothing 
• Paper and cardboard 
• The soil of houseplants 
• Laundry rooms and closets   

What Mildew Looks Like

• Flat and powdery in texture 
• White, gray, or yellow in color 
• Appearing in patches on surfaces 

Exposure Symptoms

• Mild coughing 
• Headaches 
• Minor respiratory irritation 
• Sore throat 
• Allergic reactions in some individuals 

How to Identify Black Mold vs. Mildew 

It’s easy to confuse mold and mildew. After all, they both tend to grow in the same areas. However, knowing the difference between them matters because their health risks and cleanup methods are different.  

If you notice something suspicious growing in your home that could be mildew or mold, follow these steps to identify the culprit: 

Check the color: Mildew is typically white, gray, or yellowish. Black mold’s dark greenish-black. 

Look at the texture: Mildew tends to look flat and powdery. Black mold is often fuzzy or slimy, especially in humid conditions. 

Note the location: Mildew usually stays on the surface of tiles and fabric. Black mold is more likely to grow in hidden spaces, such as behind walls, under floors, or inside ductwork. 

Assess the damage: Mildew sits on top of surfaces and rarely causes structural harm. Black mold, on the other hand, can penetrate materials and break them down over time.  

Take a whiff: Mold and mildew both give off musty odors, but black mold tends to have a stronger scent.  

Still not sure whether you’ve got a case of mildew or mold on your hands? When in doubt, consult a professional. 

Mold vs. Mildew: What to Do Next

Once you’ve figured out whether you’ve got mold or mildew growing in your home, it’s time to take action.  

With mildew, you can probably tackle the cleanup on your own. For mold, calling in professional help is usually the better choice to ensure a safe cleanup, especially if you’ve got black mold. Regardless of whether you’re dealing with mildew or mold, you’ll also need to fix the underlying moisture problem, or the fungus will likely return.  

DIY Cleanup vs. Calling a Professional

If you’re confident you’re dealing with mildew, put on gloves and a mask and start cleaning. Scrub the affected area with a mixture of water and white vinegar or a store-bought mildew cleaner. Dry the area thoroughly after scrubbing and keep an eye on the space for any signs of returning mildew. 

Mold’s a different story. If the affected area is larger than 10 square feet, if it’s located in your HVAC system, or if you suspect black mold, hire a professional mold remediation service. If you try to remove mold without the proper equipment, you could end up releasing spores in the air, spreading the problem, and increasing your health risks.  

Preventing Mold and Mildew

Once you’ve banished the mildew or mold from your home, your work isn’t over. If you don’t address the underlying conditions that attracted the fungus in the first place, you’ll wind up with new growth in the future. 

The best way to prevent mold and mildew is to control moisture levels in your home. Here are a few things to consider: 

• Use exhaust fans in your bathrooms and kitchen to lower humidity levels. 
• Fix leaky pipes, faucets, and roofs ASAP. 
• Keep indoor humidity levels between 30% and 50%. Use a dehumidifier if necessary. 
• Make sure your basement, attic, and crawl space have ventilation. 
• Don’t leave wet towels, clothes, or fabrics lying around. 
• Call a remediation company if you have any water damage in your home.  

Staying proactive will help you keep your home mold- and mildew-free.  

How ServPro Can Help

Whether you’re dealing with mold or mildew, SERVPRO is here to help. Our trained technicians can identify hidden mold growth, fix recurring moisture problems, and safely remove the mold or mildew. We’ll assess your home, explain your options, and tailor a remediation plan to your situation.  

You don’t have to face a mold outbreak alone. Find a location near you for an expert evaluation. 

FAQs

What’s the difference between black mold and mildew?

Black mold is a greenish-black fungus that can grow beneath surfaces and can pose health risks over time. Mildew is a surface-level fungus that looks flat and powdery and is generally easier to clean and less harmful.  

Can I stay in my house with black mold?

That depends on the severity and location of the mold. If you notice mold in a small, contained area, you may not have to leave. Larger infestations or mold in your HVAC system can spread spores throughout your home and cause health issues. In that case, you should hire a professional remediation team.