It has been widely recognized that socially disadvantaged populations are highly vulnerable to natural disasters. Nonetheless, little is known about how disasters affect housing affordability, particularly for those who depend on public housing. Using a national sample of counties over the period 2005-2016, this study examines the effects of flooding and federal disaster aid on the provision of public housing across the United States. We estimate a panel fixed-effects model with an instrumental variable to account for the endogeneity of disaster aid. Results show that severe floods reduce the number of public housing units, prolong the average waiting time, and increase tenant-paid rents for public housing. Meanwhile, we find that the Federal Emergency Management Agency's Public Assistance (PA) aid can help restore the supply of public housing and lower the rents paid by tenants in the aftermath of flood events. Our findings suggest that natural disasters place particularly high stress on the socially vulnerable, and post-disaster aid can alleviate some of the adverse impact of disasters on those who depend on public housing.