What is the difference between obsessive compulsive and being a germaphobe?

Different feel. Although phobias and OCD both are categorized as anxiety disroders, most people feel justified with their phobias while those with OCD nearly always see their symptoms as odd or "weird" and making no sense. However, treatments are quite similar both with respect to mediations and with talk therapies.
Part of the other. Cleaning excessively can be a symptom of OCD, among may others such as checking locks repeatedly, alphabetizing books several times a day, stacking pocket change on a dresser by each coin, and others.