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Mold from water damage is a serious problem that can emerge after a flood. If areas in your home haven’t thoroughly dried, like behind the baseboards or drywall, water damage causes mold that can often go unchecked. 

Indoor mold is particularly destructive and can cause several health issues, from sneezing to severe allergic reactions in immunocompromised individuals. Acting swiftly is crucial to prevent damage to your home or building and adverse health effects on your household, employees, customers, or guests. 

What Does Water Damage Mold Look Like?

Water damage mold appears fuzzy and nearly transparent when still new. Once fully developed, however, they form unmistakable dark spots on the affected surfaces. They often appear grayish-black. However, other types of mold can also be orange, purple, yellow, and green in color.

If your property had just been flooded, observe the porous, organic surfaces like drywall, plywood, and fiberglass insulation backing that had been submerged in water. They might have retained some moisture, making them the perfect locations for mold to grow. 

Mold spores can begin to develop within 72 hours of exposure to water. It’s best to be on the lookout for visible signs of mold if it’s only been days after a flood.

Common Types of Indoor Mold

While there are various types of mold that can grow inside your home or building, it’s essential to recognize dangerous mold when you see it and arrange for its removal as quickly as possible.

There are 12 known types of water damage mold:

  1. Altenaria
  2. Acremonium
  3. Aureobasidium
  4. Chaetomium
  5. Cladosporium
  6. Fusarium
  7. Stachybotrys atra
  8. Mucor
  9. Aspergillus
  10. Penicillin
  11. Trichoderma
  12. Ulocladium


Of these 12, there are four that are most commonly seen inside houses and buildings with water damage:


  • Stachybotrys atra This is the famous and feared “black mold,” a toxic, slimy black mold with green tinges that resemble tar. It grows on cellulose or plant-based materials that often get wet. As such, black mold often appears inside walls that hide leaky indoor plumbing that has gone undetected for weeks or months. People who are sensitive to allergens or are immunocompromised might experience severe allergic reactions when exposed to black mold, so they must stay away from infested rooms and buildings at all costs. Additionally, people who remove black mold must wear proper protective gear, including masks or respirators. 


  • Cladosporium This mold is distinctive because it first appears as black dots and eventually merges into large patches of olive green and brownish-black. It is common on bathroom tiles and sinks, sheetrock, damp concrete walls, furniture, and old carpets.


  • Aspergillus This variety of mold is also black but with a bit of white and yellow. According to the CDC, many people breathe in aspergillus spores without getting sick. However, people with lung disease or weak immune systems may develop infections in their lungs and other organs. 


  • Alternaria While this variety is more common outdoors, Alternaria can ride the wind and enter your home or building. It can latch onto carpets and curtains and thrive in attics and crawl spaces. This mold grows long and hairlike; its color ranges from olive to black.


We’ve given plenty of visual descriptions of the different varieties of harmful indoor mold. But sometimes, mold grows hidden out of sight, especially in buildings with water damage. Since the risk that mold will grow is high after a flood, it’s best to be vigilant for non-visual signs of microbial growth. 

Other Signs of Mold

If mold from water damage grows in concealed areas, it will be a big problem if you discover it too late. Fortunately, mold reveals itself in other ways apart from visible deterioration and distinctive stains. 


If you notice the following in your property, it may mean that mold has taken root somewhere hidden or difficult to reach:


  • You smell a musty odor (in some cases, a foul smell could develop because of mold from water damage).
  • There are spots on wooden walls, floors, and ceilings that are water damaged.
  • Complaints that your property feels and smells dusty, even with constant cleaning.
  • People experience allergic reactions only when they step inside your property. 

Keep Mold Under Control With Restoration 1 

Asking, “What does water damage mold look like?” is just one way of keeping mold out of your property. Unfortunately, mold spores can make their way inside and often go unnoticed until the problem becomes more significant. The key to preventing microbial growth is ensuring that the flooded rooms and drenched porous materials completely dry out.


Restoration 1 of Minnetonka is fully equipped for water extraction and drying, and we have years of experience in offering mold remediation services in residential and commercial properties. We also perform preventive measures against mold. If microbial growth still occurs, our mold remediation experts can immediately come to remove the infestation before it does more damage to your property and health.


Keep your water-damaged property mold-free with Restoration 1 of Minnetonka. Schedule a consultation today.