What’s The Difference Between White Mold And Black Mold?

Molds are dangerous guests in our homes. They come in every color you can think of including white, black, gray, green, and more. Indoor molds exhibit colors like gray-green, white-green, and shades of brown.

So, what’s the difference between white mold and black mold? White mold thrives in wet environments. It’s powdery and stingy making it difficult to identify. On the other hand, black mold is the most toxic fungi found in indoor environments. It releases mycotoxins spores that can cause skin irritation, immune system degradation, and neurological breakdown.

Here is everything you need to know about the two types of mold. Let’s jump right in!

What Causes White and Black Mold?

White mold grows in areas with high moisture levels and high temperatures. The food sources for this mold are carpets, drywall, wood, and carbon-rich materials. It grows in temperatures between 2-40 degrees Celsius. As the mold spreads, it can lead to structural damage in your home. But unlike other fungal outbreaks, it doesn’t darken once it matures. Black mold contains a lot of cellulose and prefers a warm and damp environment. You’ll find it in humid areas like laundry rooms, bathrooms, and shower cubicles.

Main Characteristics Of White And Black Mold

White mold exhibit a flat growth pattern. It appears in two distinct forms: fluffy and powdery. And once it grows on a surface, you can easily remove it.

Black mold penetrates deeply into the surface and comes in different sizes. It can cause structural damage to properties.

The most distinct characteristic is that it maintains the black color during growth and development stages. With time, the fungus produces a musty odor which causes breathing difficulties.

How Long Does It Take White And Black Mold To Grow?

When white mold meets the ideal conditions (temperature and humidity), it will germinate within 1-2 days. Typically, the pores colonize within 72 hours and become visible within 18 days.

Time will change based on the amount of moisture and the affected area.

Black mold needs at least 7 days before it begins to grow and 12 days to colonize. Once it becomes toxic, the mold forces out other molds and takes over the new environment.

How Hazardous Are White And Black Molds?

According to modern science, white mold is less harmful than the black counterpart. It releases airborne reproductive stores in the environment. When inhaled, it can trigger basic allergic reactions.

Black mold is invisible and may remain undetected for years. It’s particularly dangerous for people with respiratory conditions. The toxins can compromise your immune system leading to an array of health problems.

The elderly tend to suffer from respiratory illnesses than a healthy adult. The physical signs of this type of mold include itchy eyes, airway problems, coughing, runny nose, and irritated throat.

For some people, the reaction can have severe problems like fatigue, nausea, and trouble breathing. It can also trigger flare-ups in asthmatic patients. If you take longer to remove black mold, it can be detrimental to your health.

Where Can You Find A White Mold In Your House?

White mold grows in places with food, moisture, and temperature. You’ll find it in areas like:

The Basements

They tend to be cooler than other rooms and promoting mold growth. When the outside air comes into contact with the walls, it creates moisture droplets. If they are not dried immediately, the white mold will grow. Keep in mind that the basements lack proper ventilation, thus a breeding ground for white mold. The easiest way to tell whether your basement has this fungus is the musty smell and discoloration of the walls.

Crawl Spaces

These are tight spaces that are quite difficult to dry. White mold will grow if the foundation cracks allow the moisture to enter or if the house has leaky pipes. Crawl spaces have high humidity due to poor ventilation.


They contain plenty of food for white mold. If your roof is leaking, you’ll provide the necessary moisture for the mold to thrive.


As most of us know, it’s difficult to dry a wet carpet. When damp, the fungus will have an opportunity to thrive. This is why we should avoid carpeting areas that are prone to dampness like bathrooms, laundry rooms, kitchens, among others.

Luckily, you can easily spot a white mold as it gives a musty smell. Be sure to clean and dry the carpet completely to prevent the mold from spreading. If you don’t take action fast, you may have to replace the entire flooring system.


We can’t deny the fact that white mold loves to feed on wood. This means your hardwood floor, cupboards, carpets, and other structural components are at risk. Keep an eye on common signs like white spots and discoloration on the wooden surface.

Where Can You Find Black Mold?

Because black mold needs a lot of moisture to grow, you can find it on the ceilings, inside walls, and under floors.

Also, you’ll see it in other areas like carpets and insulation that has been exposed to moisture.

White And Black Mold Remediation

Having a white mold in your house is not only embarrassing but can also cause serious health risks. Since it thrives in an area with moisture, you should check the attic of roof and wall leaks.

Other than that, you should keep the gutters and downspouts clean. During the winter season, humidity is high so the clothes may not dry completely. To keep white mold at bay, you should iron them before storage. If you want to maintain the right humidity levels in your home, you should buy a humidifier.

Black mold grows when the humidity levels are more than 90%. During heavy rains, water may drip from the roof or seep through the walls. The easiest way to prevent black mold is to inspect your roof thoroughly.

Examine the leaks on the vents, valleys, and chimneys. Also, replace any missing or damaged shingles.

Don’t forget to fit exhaust fans in damp areas like the bathroom and kitchen. Another way of increasing indoor air circulation is to open windows to allow in the fresh air.

The bottom line

White mold grows on surfaces and can easily be removed while black mold penetrates beneath the surface causing severe damage. In terms of appearance, the white mold shows a flat growth while black mold has irregular growth.

Unlike white fungi, black mold produces mycotoxins which can lead to severe health issues. Once you spot a white or black mold, you should clean up the contamination effectively. Be sure to assess how far the mold has spread.

If it covers more than 10 square feet, contact a mold remediation company.