Several recent reports have focused national and international attention on issues of climate change, drought and water supply, raising particular concerns about the southwestern United States[1]. Although there is some debate about the precipitation trends associated with climate change, there is no debate about the changes in temperatures, which cause more moisture stress in natural systems and increase demands for water increase in all sectors. Most global models predict a reduction in flows in the Colorado River of 10 to 40% in the next 100 years. In combination with rapid increases in urban demand in the west, this creates a water supply problem of a magnitude that has not been adequately anticipated by water managers. While the economic and social impacts of climate variability and change occur in specific sectors and geographic areas, the ideas for adaptation are likely finite and many of the technologies and management practices are expected to be transferable across regions. A number of water management adaptation options will be discussed, including solutions that can be optimized across watershed and state boundaries. Impacts of climate change are already visible and significant in the water sector, and there are many no-regrets strategies, including improved use of climate information at multiple time scales, available to water managers who wish to limit risk within their systems.