There are an estimated 400,000 types of mold, and about 1,000 of them are found indoors, according to a story on America Now News’ website.

From the story: “Most forms of mold aren't an issue to your health or your home until you add water. Molds can cause disease, trigger allergic reactions, and continue to do damage if they are not killed off completely. The worse it gets, the more dangerous it becomes, and the more expensive it is to clean up.”