Great Question, and a very important question! The term "Black Mold or Black Mould" is used very loosely but it actually refers to a specific type of mold, "Stachybotrys". Stachybotrys is the most health hazardous mold that you can have and in your living environment it should not be present. The scary thing is that sometimes it is not even visible to the human eye. Black Mold or 'Stachy' begins to grow when there is a water source that has not been cleaned up fast enough. If it is visible, the colour is very black, compared to other common molds. I have attached a link below that further goes over "Black Mold". Black Mold should never be cleaned up by yourself, given it's hazardous toxins. It needs to be cleaned up by a professional. If you suspect you may have black mold, give us a call and we can perform a free inspection for you!