Mold reproduces by means of tiny spores; the spores are invisible to the naked eye and float through outdoor and indoor air. Mold may begin growing indoors when mold spores land on surfaces that are wet. Indoor mold is found when moisture levels rise above 60% relative humidity in areas like attics, crawl spaces, basements and bathrooms. There are many types of indoor mold, and none of them will grow without water or moisture.
