First it's important to understand that mold is a natural organism that is present abundantly outdoors. It serves an important purpose such as decomposing organic materials, such as wood and plant materials, for example. The problem is however, that mold will sometimes invade our homes, where this is. Out of all the types of potential water damage that can occur and they are all devastating sewage water damage creates even greater risks. Sewage cleanup should never be attempted by anyone other than experts in the field.