Most cities use Department of Housing and Urban Development (HUD) programs to provide a sizable chunk, if not all, of their low-income housing stock. HUD's two most significant rental assistance programs -- Section 8 and public housing -- use federal subsidies to help needy families afford rent. You apply for these programs using the same general protocol regardless of where you live.
Ensure that you fall under the income limits HUD sets for its rental assistance programs. Each year, HUD publishes income limits that vary by location. It groups people into three categories: low-income (households with incomes at or below 80 percent of their area's median income); very low-income (income at or below 50 percent); and extremely low-income (income at or below 30 percent). The public housing program accepts applicants from all three classifications, while Section 8 uses the very low- and extremely low-income groupings.
Contact your local housing authority. You can search for the one that governs your area at HUD's website. If your housing authority does offer Section 8 or public housing, which is unlikely, or if the program is full, which is common, it might be able to assist you with other affordable housing options.
Complete an application for the program that interests you. You can apply for Section 8 and public housing simultaneously, which might cut down on how long it takes for you to receive some type of rental assistance. If your housing authority is using a waiting list, filling out an application simply gets you a spot on the list; it does not guarantee housing.
Confirm your eligibility when your name reaches the top of a waiting list or if assistance is immediately available. For Section 8 and public housing, you'll need to prove that you are a U.S. citizen or that you hold an "eligible immigration status," according to the programs' websites. You also need to verify household size as well as income. Most housing authorities accept birth certificates and Social Security numbers to identify household members, and paycheck stubs, tax returns and bank account information to document your earnings and assets.
In addition to HUD programs, some cities operate their own subsidized housing initiatives aimed at low- to moderate-income households. For instance, San Francisco's zoning code requires private developers to include a certain percentage of affordable units with market rate projects. Other cities use similar programs to increase their affordable housing stock, however, program types and availability vary widely by place. Most of these programs use HUD's income limits to determine eligibility.