That depends on the program. If you're looking at public housing programs, such as Section 8, there's likely to be a wait list. If you live in the metro area, check updates on waiting lists for public housing at HousingLink. If you live outside the metro area, contact your local Housing and Redevelopment Authority (HRA) or search online using the keywords "HRA" and the county name.
To understand your housing rights, watch a collection of fair housing videos at HousingLink.