Locate areas in your home which may have recently been damaged with water. Common areas of water damage are ceilings, basements and walls.
Look in places that are dark and damp. Typical locations for black mold growth include cabinets, the corners and base of drywall, and basements. Also look behind wallpaper that has been recently damaged, sheetrock and ceiling tiles.
Identify the mold. Black mold is characterized as being black or greenish black. It is wet and slimy to the touch. It will smell musty or like mildew.