There are insects that are actually called water bugs. However most of the time Water Bug is simply a common name for a couple diferent types of Roaches, such as the Smoky Brown Cockroach and the American Cockroach. The most common one I see in homes around Raleigh and Fayetteville is the Smokey Brown Roach (pictured above). It is almost impossible to completely get rid of these insects, to the point you will never see them. What you can do is reduce the population to an acceptable level and keep them out of your home.