California’s housing costs are among the highest in the nation. For low–income households, high housing costs can lead to problems such as frequent moves that interfere with children’s school performance or families forced to live in unhealthy substandard housing. To reduce the problems associated with high housing costs, federal, state and local governments have created an array of public programs intended to expand the supply of rental housing affordable to low income California households. By increasing the supply of affordable housing, research suggests that these policies have helped to improve the educational attainment and health of residents while increasing economic activity and reducing social services costs.