1. SRO: "Single Room Occupancy" is a room in a building that usually offers shared bathrooms and cooking facilites.  Many SRO buildings rent rooms by the week or month.  Vacancies are usually not hard to find, and you can often move in immediately.

2. Senior Housing: Housing for seniors is limited by age, usually over 60 or 65.  Senior housing may offer just apartments, or may provide meals, activities, and services.  Senior properties usually have a waiting list.  If the list is "open" you can add your name to it.  If it is "closed" the property is not accepting applications.  Waiting lists can often be several years long.

3. BMRS/Inclusionary: "Below Market Rate" can be units or buildings that are part of a larger development.  To get permission from the City to build a new property in San Francisco, developers can be required to "set aside" units for sale or rental at below market rates.  To quailify for this housing, your income must be lower than a certain percentage of the median income for the City.  A larger family or household will have a higher income limit.

4. Public Housing: This housing is owned by the City (SFHA) or the federal government (HUD).  The housing can be townhouses or apartments, sometimes in large tall buildings (usually for seniors) or spread out over an area with two to three floor buildings (usually for families).  Public housing is limited to people with low incomes, and requires you to apply and go on a waiting list. You may be offered a vacancy in another part of town if it becomes available.  Certain groups of people may get a priority and a higher place on the waiting list.

5. Supportive Housing: Supportive housing is offered in a building that also contains a variety of service providers.  It is sometimes called "transitional" housing.  Usually you need to apply or be referred for this type of housing because of a special need, and meet income standards.

6. Section 8: This is a rent subsidy program.  Under this program landlords agree to accept a Section 8 voucher from a tenant, who pays a certain percent of income as rent, with the Section 8 program paying the rest.  You must apply to the City for Section 8, be approved to receive a voucher, and then find an apartment or house on your own.