Public housing is assisted under the provisions of the U.S. Housing Act of 1937 or under a state program having the same general purposes as the federal program. Public housing provides decent and safe rental housing for eligible low-income families, the elderly, and persons with disabilities. It can come in all sizes and types, from scattered single-family houses to high-rise apartments for elderly individuals. The U.S. Department of Housing and Urban Development (HUD) administers federal aid to local public housing authorities (PHAs) that manage the housing for low-income residents at rents they can afford. Public housing is limited to low-income families and individuals. There are approximately 1.3 million households living in public housing units, managed by some 3,300 PHAs.