The availability of abundant clean water and the assurance of its continuity over the long-term is one of the biggest challenges facing our world today. Unlike in the past, however, a wealth of hydrologic and water quality data and/or associated land use, land management, and climate data exists. Furthermore, there has been a phenomenal increase in computational capacity in recent times. This in itself presents enormous opportunities to transform how we make and manage water quality decisions since analytics no longer have to be confined to small, “manageable” datasets. In this presentation, ways to reduce complexities associated with the volume of water quality data, number of parameters to be interpreted, and the many possible modes of presentation are discussed. Hydrologic and water quality modeling applications are also discussed. Finally, some challenges associated with Big Data applications in water quality decision making and management are presented along with some potential solutions.