This October 2009 report is an early cost assessment of adaptations to address some of the likely impacts of climate change on our nation’s drinking water and wastewater utilities through 2050. This time period is selected because it represents the timeframe within which we best understand climate change effects and their impacts on drinking water and wastewater utilities, and it is consistent with the typical planning horizon of many utilities. The assessment indicates that the cost to utilities could range from $448 billion to $944 billion.