Understanding the Difference between Mold and Mildew

Jun 15, 2023 | Plumbing

What is the difference between mold and mildew? Mold and mildew are two fungi that thrive in damp and humid conditions, often causing havoc in buildings and homes. Although they are similar in nature, mold and mildew have distinct differences in growth patterns, effects on health, and treatments. In this blog, we will enlighten you on the key differences between mold and mildew.

Definition and Characteristics

Both Mold and mildew are microscopic fungi that grow in moist environments. Mold often appears in shades of green, blue, or black, and can be fuzzy or slimy in texture. It can grow and spread quickly, damaging walls, ceilings, and even furniture.

Mildew, on the other hand, is a lighter shade of gray or white, and it has a powdery appearance. It usually grows on surfaces that are relatively easier to clean, such as walls, fabrics, and shower curtains. Unlike mold, mildew does not cause severe damage to surfaces. Both microbial volatile organic compounds can cause allergic reactions and there is a very real difference between mold and mildew and how they’ll effect your health.

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Mold and mildew thrive in damp and humid conditions, making areas such as bathrooms, kitchens, and basements their favorite breeding grounds. Poor ventilation, water leaks, high humidity, and floods can encourage their growth and spread. However, mold can be more dangerous as it can grow and spread for several years unnoticed, leading to severe structural damage and health risks.

Health Risks

Both mold and mildew can cause several health problems, especially if the mildew or mold spores are inhaled. Common symptoms include runny nose, sneezing, coughing, sore throat, skin irritation, and itchy eyes or eye irritation. However, mold is more hazardous as it can cause more health risks and severe complications such as respiratory infections, difficulty breathing and asthma attacks, and even lung damage in individuals with compromised immune systems.


Mold and mildew look similar and are often mistaken for each other, but they have distinct physical appearances. Mildew appears as a thin, powdery, and white or grey growth on surfaces. It affects surfaces such as fabrics, leather, walls, leather, and paper. Mold, on the other hand, appears as black, green, or blue fuzzy patches. It affects surfaces such as bread, fruits, walls, wooden frames, and carpets.

Level of Toxicity: Mold VS Mildew

Mold is more toxic than mildew. Mold has been associated with respiratory problems, allergies, and other health concerns. It releases mycotoxins, which can be harmful in large doses. As for mildew, it does not usually pose significant health risks to humans. However, prolonged inhalation of mildew spores may cause respiratory problems.

Growth Patterns

Mildew develops on the surfaces of materials, while mold thrives in damp and humid environments or surfaces. Mold grows in colonies, which give it a fuzzy or slimy appearance. Mold thrives in damp, dark, and humid places, such as bathrooms, basements, and attics. Mold can grow on carpets, paper, drywall, and insulation. Mildew thrives in warm, damp, and humid places such as textiles (like shower walls), fabrics, and rubber.


Preventing mold and mildew requires maintaining dry and clean conditions. This could include properly ventilating the home, using a dehumidifier, and repairing leaks immediately. For areas prone to mold growth, reducing indoor humidity levels to below 70% is crucial. Additionally, drying out clothes and other wet items immediately, fixing roof leaks, and using mold-resistant paint can prevent mold growth.

The Different Types of Mold and Mildew

Mold and mildew is a common problem that often appears in damp and humid environments. They can grow on a variety of surfaces, including wood, drywall, and even clothing. However, not all mold and mildew are created equal. In fact, there are many different types of mold and mildew, and knowing the difference between them can help you take the proper steps to get rid of them.


Alternaria is a type of mold that commonly grows on walls, countertops, and other damp surfaces. It’s typically green or brown in color and has a fuzzy texture. Alternaria spores are known to cause allergy symptoms such as itchy and watery eyes, runny nose and sneezing. The best way to prevent Alternaria growth is to ensure you keep all surfaces dry and well ventilated.


Aspergillus is a type of mold that can appear in both indoor and outdoor environments. It’s often found in areas with high humidity and can grow on almost any surface, including food, textiles, and wallpaper. Aspergillus can lead to respiratory issues such as asthma, so it’s important to keep your home dry and well aired.


Cladosporium is a type of mold that’s found in both indoor and outdoor environments, including bathrooms and kitchens. It can cause respiratory symptoms such as coughing and wheezing, as well as eye irritation and skin rashes. Although not always hazardous, it’s still important to identify and remove Cladosporium from your environment.


Penicillium is a common type of green mold or blue mold that’s often found in damp spaces, such as basements, bathrooms and kitchen countertops. It’s been known to cause respiratory problems, such as coughing and wheezing, as well as sinus infections. Penicillium is also known for contaminating food, so be sure to check your food for any signs of mold before consuming.

Stachybotrys Chartarum

Stachybotrys is a toxic black mold that grows in moist and humid environments. It has a slimy texture and can appear in spots on walls, paper, or even clothing. Exposure to Stachybotrys can cause severe respiratory problems, such as coughing, wheezing, and chronic lung disease. It’s important to call in professionals to deal with Stachybotrys as part of a home and office mold inspection.

Downy Mildew

Downy mildew is a common type of mildew that frequently develops on vegetables, plants, and fruits. It can cause considerable damage in a heartbeat on crops, including leaves turning yellow, brown spots, and stunted growth. It also produces a fuzzy, gray or purple substance on the affected plants’ underside parts. The primary cause of downy mildew is dampness – it thrives in humid climates and during damp, wet periods, making proper sanitation and prompt removal of affected plants the best way of control. Fungicides and preventive measures like monitoring weather forecasts can also help prevent further damage.

Powdery Mildew

Powdery mildew is another familiar type of mildew that often occurs on indoor and outdoor plants. It appears as white or gray powdery substance that covers leaves, fruits, or flowers, causing them to deform and affecting the overall beauty of the plant. It thrives in warm, dry climates, making proper hydration and air circulation essential in keeping it at bay. Powdery mildew is easy to prevent by regularly pruning infected sections and applying fungus control treatments.

White Mold

White mold is a destructive type of mildew that affects crops such as beans, peas, mushrooms, and tomatoes. It appears as a white, fluffy substance that covers the surface of the crop, causing them to decay. The primary cause of white mold is poor ventilation and humidity; thus, it is advisable to provide adequate spacing between plants, proper watering, and hygiene of the farm.

Yellow Mold

Yellow mold is the rarest of all mildews, but it poses a risk to human health. It often appears on walls, wood, or foods. It can cause allergies, dizziness, and respiratory disorders in individuals. Yellow mold thrives in damp environments, making it essential to maintain proper ventilation, airflow, and temperature regulations. One can also use antifungal chemical treatments in severe cases.

The Causes of Mold and Mildew: What You Need to Know

Mold and mildew are common issues that homeowners face, and they can be difficult to get rid of once they take hold. Not only are they unsightly, but they can also cause health problems for people who are sensitive to them.


One of the main causes of mold and mildew is high humidity levels in your home. When the air is too humid, it creates the perfect environment for these fungi to grow. If you live in an area with high humidity, it’s important to keep your home well-ventilated, use dehumidifiers, and avoid leaving wet clothes or towels lying around. Moisture management problems are the leading cause of mildew and mold problems.

Leaks and Moisture

Another significant cause of mold and mildew is leaks and moisture. If there are any leaks in your roof or walls, or if there’s a leaky pipe under the sink, it can create water damage and a damp environment that’s perfect for mold and mildew to grow. It’s important to fix leaks as soon as possible and to address any moisture issues in your home.

Poor Ventilation

Poor ventilation can also be a contributing factor to mold and mildew growth. When air can’t circulate properly, it can create pockets of stagnant air that are perfect for fungi growth. Be sure to use exhaust fans in your bathrooms and kitchen, and open windows and doors whenever possible to encourage air flow.

Organic Matter

Mold and mildew thrive on organic matter such as wood, paper, and cloth. If you have any food scraps or organic waste lying around your home, it can attract mold and mildew. Additionally, if you have any wet, damp, or poorly ventilated areas in your home where organic matter is present, it can provide a breeding ground for fungi. Make sure not to throw damp socks in your laundry hamper!

Lack of Maintenance

Finally, a lack of maintenance can cause mold and mildew to grow. If you don’t keep your home clean and tidy, it can attract fungi. Additionally, if you don’t maintain your HVAC system and keep air filters clean, it can lead to poor air quality in your home. Make sure to keep your home clean and address any maintenance issues promptly to prevent mold and mildew from taking hold. Don’t forget to check your crawl spaces!

How to Clean Mold and Mildew – Your Ultimate Guide

Mold and mildew are unsightly, unhealthy, and sometimes even dangerous. When left untreated, they can lead to respiratory problems, allergies, and structural damage to your home. But don’t worry; cleaning up mold and mildew is easier than you might think. If you have a mildew or mold problem, use these tips to treat mold and mildew.

Identify the Source

Before you start cleaning up mold and mildew, it’s essential to identify the source of the problem. Is it a leaky roof, a plumbing issue, or poor ventilation? Addressing the root cause of the mold and mildew growth will prevent it from coming back.

Use a Mold and Mildew Remover

There are many effective mold and mildew cleaners on the market, but not all are created equal. Look for a product that is specifically designed to remove mold and mildew, and check the label to ensure that it’s safe for use on the surface you’ll be cleaning. Be sure to follow the manufacturer’s instructions carefully.

Try Natural Remedies

If you prefer a more natural approach to cleaning, there are several remedies you can try. Vinegar is a potent natural cleaner that is effective against mold and mildew. Using household items, mix equal parts white vinegar and water in a spray bottle and apply to the affected area. Baking soda is another natural remedy that can help eliminate mold and mildew smells. Mix 1/4 tablespoon of baking soda with water to make a paste, then apply to the affected area.

Wear Protective Gear

When cleaning up mold and mildew, it’s essential to protect yourself. Wear gloves, long sleeves, and pants to avoid contact with the mold and mildew spores. You may also want to wear a respirator to avoid inhaling the spores.

Prevention is Key

The best way to deal with mold and mildew is to prevent it from happening in the first place. Keep your home well-ventilated, fix any leaks promptly, and minimize moisture in your bathrooms and kitchen. Regular cleaning and maintenance can also prevent mold and mildew from taking hold.

MD Sewer & Plumbing

When it comes to preventing mold and mildew in your home, you might not think to call on a plumber. But in reality, a plumber can be your first line of defense against these nasty spores that can wreak havoc on your health and home. How, you ask?

Well, a plumber can help identify any leaks in your plumbing system that might be causing excess moisture in your home. Moisture is a breeding ground for mold and mildew, so fixing those leaks is crucial. Additionally, a plumber can install proper ventilation systems to help keep moisture levels low and prevent mold and mildew from taking hold. Don’t let these pesky fungi take over your home – call a MD Sewer and Plumbing today and keep your space safe and healthy!

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In summary, understanding the difference between mold and mildew is crucial in identifying the best practices for prevention and eradication. The biggest difference between mold and mildew is that mildew is superficial and less toxic, while mold is more toxic and requires professional removal. While that are different, certain kinds of mold and mildew can be hard to the naked eye to tell apart due to their many similarities.

By maintaining dry and clean conditions, using preventative strategies, and seeking help from mold removal professionals, you can avoid health risks and keep your home or building habitable. Remember, no amount of mold or mildew is safe, so take the necessary steps to prevent and eliminate them promptly.

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