Climate change will bring about unprecedented economic, social and environmental effects, which require both the mitigation of greenhouse gas emissions and adaptation to its adverse effects. Water is the main element through which the impacts of climate change will be felt. Climate change results in increased uncertainties, complexities, stress and potential for conflicts within water management, both among and within states. New forms of governance are needed if the world is to respond to the need to adapt to changes in freshwater supply and to manage water security risks. This paper suggests that adaptive governance should to be main-streamed into all water regulation to ensure the availability of and access to safe water resources and to prevent water-related conflicts. The paper discusses the concept of water security in the context of climate change, the threats that climate change poses to water security, and the concept and implications of adaptive governance as a possible solution. The application of adaptive governance requires a certain degree of institutional and normative flexibility, instruments and institutions that can respond and adapt to changes and manage the level of uncertainty associated with the impacts of climate change. The governance institutions, methods and instruments should be responsive to new information and different kinds of uncertainties, while reflecting the vulnerabilities, capacities, needs and priorities of both societies and ecosystems in the face of climate change. Water security risks could be reduced by increased hydrosolidarity among states, which would present the challenges posed by climate change on water governance and security as primarily an opportunity for new forms of cooperation.