This chapter discusses the Blue, Green, and Red Agendas of water law and policy. Thousands die every day from diseases related to water. Yet water law largely focuses on two agendas. The first agenda, the Blue Agenda, focuses on water supply and sustainability. The second agenda, the Green Agenda, focuses on water quality in nature and for human use and consumption. These two agendas often ignore, or are implemented in ways inconsistent with, the “Red Agenda.” The Red Agenda focuses on the prevention of waterborne infections, like cholera, and the control of water-related disease vectors, like mosquitoes transmitting malaria. Laws motivated by the Blue Agenda, like building a dam or irrigation system, can interfere with the Red Agenda by bringing mosquito habitat closer to humans. And laws motivated by the Green Agenda, like prohibiting discharges of pesticides into a river, can interfere with the Red Agenda by preventing a response to a malaria outbreak. This chapter describes these agendas, how and why they conflict, and how they can be better reconciled to achieve water security in public health.