Brenner, Moran, Stallman, Gilchrist and McVan, (2006) recommended that “swimming ability be promoted as a necessary component of water competence, but with the understanding that swimming ability alone is [often] not sufficient to prevent drowning” (p. 116). Tradition and expert opinion are no longer enough. Science can now help us select essential competencies. What does research evidence show us about the protective value of specific individual personal competencies? Since the term “water competence’’ was coined by Langendorfer and Bruya (1995) and adapted for drowning prevention by Moran (2013), it has gained in use and acceptance. As a construct, it is indeed more inclusive than “swimming skill’’ alone for addressing drowning prevention. Our proposed taxonomy of water competencies re-emphasizes the need for a broad spectrum of physical aquatic competencies as well as the integration of cognitive and affective competencies. The purpose of this review article is to a) identify all the key elements of water competence, b) support each recommended type of water competence with examples of research evidence, and c) suggest areas requiring further research.