This article identifies the conditions of vulnerability and risk to climate change presented by the city of Pedernales (Ecuador) in relation to water. It characterizes these problems according to four axes: the state of water resources, the forms of occupation on riverbanks, the mechanisms of water circulation, and the sociocultural system of use of this resource. Then he describes how the adaptation approach based on an urban design sensitive to water can reduce the vulnerability generated by pollution of the banks of the main river in the city.