Is black mold on my walls bad? Not every black mold is bad but all molds should be treated as potential health hazards. The only way to tell whether the mold is bad or not is to have it tested by a qualified mycologist (i.e., a person who is qualified to correctly identify yeasts and molds). But regardless of whether the mold is of health concern or not it should be removed for a number of good reasons. First, mold damages any organic material it grows on. Secondly, mold is unsightly and we don't want to see it growing on the walls of our houses.

It is important to remember that mold growth is an indication of moisture problem. Therefore, the key to controlling mold growth indoors is to eliminate moisture.