The 30 percent standard comes from federal housing policy. Households that pay more are considered cost-burdened, and those paying more than half are severely cost-burdened. In 2023, a record 22.6 million renter households, about half of all renters, were cost-burdened, according to Harvard's Joint Center for Housing Studies. That included 57 percent of Black renter households.
The shortage is worst at the bottom. In 2025, the National Low Income Housing Coalition estimated a shortage of 7.1 million affordable and available homes for extremely low-income renters. Black, Latino and Native households are overrepresented in that group because of wage gaps, wealth gaps and past housing discrimination.
The main federal tools are the Low-Income Housing Tax Credit, created in 1986, Housing Choice Vouchers and public housing. None is funded to meet the need. Exclusionary zoning also limits where affordable homes can be built. Affordable housing matters because housing costs shape everything else a family can afford, including food, health care and savings.