There are a variety of types of cockroaches, the German cockroach species (Blattella germanica) being the king of them.  This is the most common type of roach, this common household pest infests homes because they are the most prolific breed and can create an unacceptable cockroach population faster than you can imagine. They can be found in nearly every home and business, yet are the hardest to get rid of because they can reproduce for the rest of their life with only mating one time!