Water and destruction garner the attention in flood disasters, and drive research and policy emphasis on physical processes and built environment impacts. But the main reason we care about floods is their effect on people. Social processes are central to explaining and driving differential disaster impacts, such as who lives in the floodplain and who faces barriers in recovery. Scientific understanding of these processes has been used to develop social vulnerability indicators. This presentation describes current understanding social vulnerability to floods, its measurement challenges using spatial indicators, and policy relevance in a national environment increasingly focused on social equity.