Mold vs Mildew – What’s the Difference?

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What is the difference between mold and mildew?

People commonly confuse mold vs mildew, considering them both the same thing. They are not, and mold or black mold can be a serious health hazard and can be damaging to your home so it is important to learn the differences. Both can cause serious health issues and allergic reactions and any toxic mold or mildew should be promptly addressed, cleaned, or removed. 

Mold and mildew are both types of fungi, but they grow differently and have different effects. Mold grows in a roundish pattern and usually rises above the surface, while mildew has a flat surface and can be slimy and greenish-black, sometimes looks powdery, and often grows in a pattern that looks like a spill. They both thrive in moist and warm areas but mildew growth is often found in cracks like on bathroom grout or other damp surfaces, while mold has a fuzzy appearance. 

mildew vs mold

Mildew typically grows on a damp surface and can be killed and removed fairly simply. Mildew removal is usually not difficult. Mold can actually grow into porous materials like wood, drywall, or carpets and often require the removal and replacement of these materials. Professional mold inspection, mold testing, and mold remediation may be required.  

Mold spores and mildew spores are both dangerous but mold can produce mycotoxins that can cause serious respiratory disease. Mold removal is always recommended and mildew growth or a mold problem should never be ignored

What are some common types of mold and mildew?

Mold can be found in a variety of colors, including black mold, white mold, green mold and even orange mold. It comes in various types such as aspergillus, cladosporium and stachybotrys atra or stachybotrys chartarum (black mold).

mold vs mildew

There are many harmless mildews but there are some toxic household mildews that are dangerous. Basidiospores are found on wood when dry rot is present. The spores eventually become mushrooms. Plants in your home can carry botrytis. Aspergillus is dangerous mildew and aureobasidium is what is often known as bathroom mold.

Are mildew and mold exposure dangerous to your health?

Yes, both mildew and mold exposure can be damaging to our health. They can cause an allergic reaction, headaches, nausea, a sore throat, breathing problems, or more. Both can release spores that a human being or pet can inhale causing a number of potential health problems up to and including respiratory problems. Allergies, asthma, eye irritation, respiratory issues, and headaches are common symptoms of toxic mold.

What causes mold and mildew in your home?

Both mold and mildew are microscopic and grow in warm and moist areas. Both are spread by spores and require organic material in order to grow. Mold spores are microscopic and easy to inhale. Mold continues to produce breathable spores and so must be addressed promptly. Mold grows indoors on walls, ceiling, and other porous materials like carpets and furniture. It very often grows as a result of water damage due to leaky pipes, storms, roof leaks, or appliance leaks. 

The combination of high humidity and high moisture produces ideal conditions for mold growth. Flooding or severe storms are frequently followed by mold growth. Mildew is often powdery and flat. It is not as likely that you will be exposed to toxins from this as from mold. It is often found on damp surfaces and items like paper, furniture fabrics, and other household items that may get wet such as bathroom items. 

Mildew is very common in bathrooms which are naturally damp and provide organic materials for it to thrive on. You may also find it on the wallpaper, plants, and wooden furniture. Damp basements are another haven for mildew and homeowners may use dehumidifiers to fight the mildew smell. Mildew loves damp and dark conditions.

Where do mold and mildew grow?

Mold and mildew grow on damp surfaces and flourish in warm areas. Some common areas in your home for mold growth is around the areas of any leaks or water damage, in or around air conditioning, basements, crawl space laundry rooms, closets, under sinks, in a front load washer, refrigerator door deals and drain pans, under sinks, and window sills.

What mold vs mildew inspection and testing is available?

If you see clear signs of mildew, there is no need for testing and you can move right to the assessment and clean up phase. Likewise, if you see clear signs of mold, there is no need to test. Move on to mold assessment and mold remediation by calling a mold remediation company. 

mold testing

Some signs of mold in your home are mold or musty smell, visible signs of mold growth, water damage such as a leak or flooding, or signs of health symptoms in you or your families like coughing or nausea. If you are purchasing or selling a house, you may also want to have a mold inspection.

There are several types of mold testing including air testing and surface testing. A mold inspection or remediation company can conduct these tests. For more on mold testing see:

How to prevent mold growth and mildew growth in your home?

Mildew and mold prevention are something every homeowner should have top of mind. Mold and mildew growth can not only be unpleasant and cause musty odors but it can be hazardous to your health and can cause damage to your home, up to and including structural damage

Mold spores can easily spread and steps in mold prevention and mildew prevention can be taken. Here are some tips for mildew and mold prevention. While you could never make your home mold-proof you can take steps to minimize mold.

  • Inspect your home regularly to look for problems areas like a basement that floods, condensation on your air conditioner, windows, or elsewhere, water stains, or recurring leaks. You may be able to prevent mold by removing wet carpet from the basement, fixing your gutters, repairing appliances, or even waterproofing your roof.
  • Mold needs dampness to grow so wipe up and clean any wet areas immediately. Leave your front load washer open after use, and don’t leave wet clothes in the dryer, dry the bathroom after a shower, and be vigilant for damp areas. Leave the bathroom door open after a shower.
  • Reseal your bathroom grout if you have tiling.
  • Be sure to install and use proper ventilation Vent appliances properly and use fans and vents as appropriate. Use our air conditioner and dehumidifiers and if your house is unoccupied be sure to monitor.
  • Monitor the humidity levels in your home and try to keep it between 30 and 60 percent. You can purchase an inexpensive humidity meter from the hardware store.
  • If building or remodeling use mold-resistant products such as drywall and floors.
  • If there is drainage outside your home be sure to direct it away from the house.
  • Maintain your gutters and keep them free of debris that could cause backups.

Mildew and mold removal – How to clean mold and mildew

mold vs mildew removal

Here are some easy DIY tips for cleaning those spots that invite mildew.

  • Grout – Wear rubber gloves and eye protection and use a brush with 3/4 cup bleach to one gallon of water. Let it sit for 10 minutes then rinse with clean water. Clean a small area at a time and be sure the room is ventilated.
  • Wash your shower curtain on hot and replace our plastic liner frequently.
  • Wet towels and fabrics should be washed with bleach.
  • Surfaces like wood cabinets or paneling should be vacuumed to remove spores. Then clean with dishwasher detergent and water. Dry immediately and don’t get it too wet.
  • Painted surfaces can be cleaned with bleach and water – again wear rubber gloves and eye protection. Le the solution penetrate for 10-15 minutes before rinsing with water.

Here are some mold clean up tips:

  • If your mold damage is extensive you will need to hire a professional mold removal company. Trying to do this yourself could cause health hazards and potentially make the problem even worse. A couple tops for small DIY mold situations:
  • Do not use bleach on mold. It will not kill it and it will return. Borax mixed with hot water (1 cup to one gallon) is a better choice. Don’t use this on porous surfaces.
  • Painting over is not a solution- it will not kill it.
  • Always wear gloves, eye protection, proper coverage and contain the area you are working in.
  • Again – any DIY mold remediation and clean up is not for anything but the smallest areas of non-porous surfaces.



  1. […] Professionals use industrial-grade dehumidifiers, air movers, and other special equipment as well as disinfectants and antimicrobials to prevent mold and mildew. […]

  2. Thank you for pointing out that it is a good idea to contact a professional if you have extensive mold damage. My wife and I are in the process of remodeling our bathroom, and we found a ton of mold when we removed the sink and cabinets. We don’t want to expose ourselves to harmful mold spores, so hiring a professional makes a lot of sense.

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