For the past forty years, federal, state, tribal, and local governments have worked diligently to identify and address water pollution problems. As a result, our drinking water is safer, our rivers, lakes, and coastal waters are cleaner, and the health of our wetlands and watersheds is improved. In 2008, the EPA National Water Program Strategy: Response to Climate Change described the emerging scientific consensus on the potential impacts of climate change on water resources. Increasingly, impacts are being observed in communities across the nation and are expected to continue, including: Increases in water pollution problems due to warmer air and water temperatures and changes in precipitation patterns; Impacts on water infrastructure and aquatic systems due to more extreme weather events; Changes to the availability of drinking water supplies; Waterbody boundary movement and displacement; Changing aquatic biology; Collective impacts on coastal areas; and Indirect impacts due to unintended consequences of human response to climate change. Despite increasing understanding of climate change, there still remain questions about the scope and timing of climate change impacts, especially at the local scale where most water-related decisions are made. These challenges require us all to come together to find the tools needed to understand and manage risks and to build resilience of both the built and natural environments. This National Water Program 2012 Strategy: Response to Climate Change builds on the momentum gained while implementing the 2008 Strategy. It provides a road map for where we need to go over the long term and articulates a set of mid-term building blocks, i.e., strategic actions that need to be taken to be a "climate ready" national water program. This 2012 Strategy emphasizes working collaboratively, developing tools, managing risk, and incorporating adaptation into core programs. Many programs and activities already underway become even more important in light of climate change -including strengthening preparedness for extreme weather events, protecting healthy watersheds and wetlands, managing stormwater with green infrastructure, and improving the sustainability of water infrastructure through energy and water efficiency.