Why Test for Mold in Dust? Mold growth is not always visible to the eye and can be hidden in many areas of your home. Anytime you have a water leak in your home, such as a roof leak or pipe burst, mold will begin to grow on the building material inside your walls often leading to a musty smell in the air. After you identify and fix the water leak, the mold will then dry and those same mold spores end up in the dust on your floors and inside the carpet. As you move around your home you will kick up those dried mold spores and inhale them causing irritation to the occupants. This test will allow you to collect the dust in your home and then identify if any mold spores are present.