The Oriental Cockroach is primarily an outdoors pest. They are larger than most Cockroaches, and are very darkly colored brown or black. Oriental Cockroaches are found primarily in sewers, under rocks, or in dense piles of vegetation. They require high-moisture environments in order to survive, which make the interior of your homes inhospitable.
Typically, if you find one of these Cockroaches in your home, it is close to dying if not already dead. Sometimes they are found in garages or sheds where they have ventured in, but could not find their way back out. If you are finding this Cockroach in your bathroom, kitchen, or sink, they have found their way up a drain. In most cases, if you keep your drains closed or covered when not in use, you will not have a problem with this pest. Exterior preventative treatments can keep their exterior population in check, and minimize that amount of activity you see outside.