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  • Mold Vs Mildew: The Difference Between Mold And Mildew


Black Mold Growth

If you are unsure of the difference between mold and mildew, you’re not alone. Both are members of the fungi family, and thrive in warm and humid conditions. Both cause health problems for humans if inhaled or ingested.  

While mildew and mold share many similarities rather than differences, you need to know how to tell them apart and understand what to do if you find either of them in your home or business. 

We'll explore mold vs mildew in more detail.


Coming in a variety of colors, patterns, and textures, all molds are different types of fungus that consist of colonies of small organisms. Mold can be found in almost any environment, in any climate and location, and can be black, white, grey, orange, green, and pink. 

While dangerous to find inside our homes and businesses, molds play an important role in nature, breaking down dead organic materials including leaves, plants, and trees. 

Molds, like mildew, thrive on humidity and moisture and reproduce through tiny, nearly invisible mold spores that travel through the air. We’re all exposed to mold every day. There are well over 100,000 known species of mold, most of which are harmless to humans. 

Some species that are prone to growing indoors can cause damage to your home and make you sick like the dangerous black mold (Stachybotrys).


Mildewed Wall

Mildew is just a specific type of mold; FEMA describes mildew as an early-stage mold. Like most mold species, mildew is a microscopic fungus that travels through air through microscopic spores. When these spores land on surfaces in damp or humid environments, it begins to colonize and grow.

Mildew grows on top of flat surfaces and often collects in places like the grout between your bathroom tiles.

While mildew should always be removed as soon as possible, it’s generally easier to identify and remove. Mildew sits on top of the surfaces it grows on, making it easier to remove safely. Unlike most mold types, you can generally remove mildew with a quality household mildew cleaner and a scrub brush.

There are different types of mildew including downy mildew which mostly grows on agricultural products and powdery mildew which is found on flowering plants.  


Mildew thrives on nearly any organic damp surface including clothing, fabric, paper, leather, walls, drywall, ceilings, and floors. These are a few of the most common types of mildew found indoors:

Basidiospore Mildew

Appears on dry rotted wood. The spores will become mushrooms and may cause mild to severe allergic reactions.

Aureobasidium Mildew

AKA “bathroom mold.” It’s most often found in showers and bathtubs.

Botrytis Mildew

Found in humid areas such as greenhouses and indoor house plants and can trigger mild to severe asthma symptoms.

Rhizopus Mildew

Very dangerous to those with pre-existing health conditions or nutritional and immune deficiencies. This toxic mildew grows on garbage, dirt, and food.


But what exactly are the differences? How do you identify mildew vs mold and what are the differences to our health and well-being if we’re exposed to it?

Mold Vs Mildew Appearance

It's easy to misidentify mildew from common molds. So “How do I know if it’s mold or mildew?” 

Mildew typically appears grey, or white, but does darken and can appear brown or even black as it ages. Mold, on the other hand, can be blue, red, yellow, or black, although many species also start white and become black or brown over time. The color alone can be hard to distinguish between mildew and mold as both change color over time.  

More noticeable differences between mold and mildew are their smell and texture. 

Mildew always grows flat and has a powdery texture and a musty smell, sort of like damp socks. Mold, on the other hand, is usually raised, irregularly shaped, and has a fuzzy or slimy texture. Mold has a pungent and unappealing smell and produces more volatile organic compounds (VOC’s)

Mold Vs Mildew Health Effects

Mildew and mold have different effects on the surfaces they grow on and the people who live near them. 

Health Risks Of Mildew

Is mildew harmful to your health? The short answer is yes. It can be quite toxic, but not generally as harmful as mold. While mildew is most often known for its effects on rotting plants, food, and crops when it grows outdoors, it can still negatively affect your health if inhaled or ingested.

If inhaled, mildew spores may cause mild to severe allergic and asthma reactions and other issues such as:

  • Sinus conjunction
  • Irritated eyes, nose, & throat
  • Headaches
  • Wheezing
  • Coughing

If mildew is not removed as soon as possible, it can continue to grow and spread throughout an indoor space. The longer the mildew exposure, the higher the chance of developing mildew & mold sensitivity. 

While mildew can damage plants and food, it typically doesn't cause damage to property as it only grows on surfaces and doesn’t penetrate below the surface.  Mildew is less threatening in general than mold, but should not be ignored. 

Health Risks Of Mold

Health Risks Of Mold & Mildew

The effects of mold are often much more serious than mildew. People with allergies, mold sensitivity, weakened immune systems, the elderly, and newborn babies are particularly at risk. 

Reactions to more dangerous mold varieties such as mycotoxins produced by black mold can lead to severe and even life-threatening issues including:

  • Respiratory issues
  • Lung disease
  • Migraines
  • Fatigue
  • Depression
  • Heart problems
  • Allergic reactions and asthma symptoms
  • Various types of cancer.  

Unlike mildew, mold can eat away at organic materials and can damage whatever it grows on including fabric, and drywall, and even compromise the structural integrity of a building's foundation or roof. The more you know about mold, the better chance you'll have to prevent suffering from mood-related illness.  

Check Out Our Ultimate Guide To Mold


Mildew is often seen growing in the shower, window sills, laundry rooms, basements, attics, or other places with higher humidity and moisture. Mildew needs similar conditions to mold growth including a food source, oxygen, moisture, and usually darkness.  


Because mildew only grows on surfaces and doesn’t penetrate beneath, it’s much easier to clean. Most commercially available cleaning solutions and scrubbing brushes will get the job done. Mildew can still cause adverse health reactions and should be cleaned with caution and care.  

Here are a few mildew cleaning tips:

  • Clean in well-ventilated areas with open windows or doors if possible
  • Wear a face mask or other face protection when cleaning mildew
  • Avoid putting your face too close to the mildew or breathing in spores
  • Avoid breathing in the fumes from the cleaning products
  • Wear good rubber gloves to protect your hands

Mold is much harder to clean and remove as microscopic spores penetrate deeper into materials. Once beneath the surface, mold can’t be wiped away like mildew. The mold issue is that it’s only visible when the colonies begin growing, making early detection, removal, and mold prevention extremely difficult. 

Because many household mold varieties contain dangerous mycotoxins which can easily spread if not properly handled, you should not attempt to remove mold on your own.  

Always contact a certified mold specialist who will have the tools, safety equipment, and experience to do the job right. These mold and mildew experts ensure not only the safety of your living environment and the air you breathe, but also give you peace of mind. 


The best strategy for mildew and mold prevention is to remove the source of moisture. Good preventative practices now prevent costly and inconvenient remediation down the track. 

Here are a few tips to keep the mildew and mold away. 

  • Keep surfaces dry - Remember to leave your washing machine door open between uses and dry to dry bathroom and kitchen surfaces to prevent mold and mildew. 
  • Change your HVAC filters - HVAC and HEPA filters must be changed regularly to work efficiently and prevent growth. 
  • Use a dehumidifier - If you are having trouble keeping humidity levels down (ideally below 50%), use a good quality dehumidifier. 
  • Regular home inspections - regular home inspections and mold inspections will ensure that no mold or mildew is hiding in areas you cannot see. They have special equipment that detects mold and mildew behind walls, under floors, and in hard-to-reach areas. 

Have questions? Need professional mold remediation or further device on removing mildew yourself? Call Mold Removal Winnipeg today and speak with one of our experts.