California Code, Health and Safety Code - HSC § 17929

(a)(1) For a mixed-income multifamily structure, both of the following shall apply:

(2) A mixed-income multifamily structure shall not isolate the affordable housing units within that structure to a specific floor or an area on a specific floor.

(1) “Affordable housing unit” means any residential dwelling unit that is restricted by deed or other recorded document as affordable housing for persons and families of low or moderate income, as that term is defined in Section 50093.

(2) “Common entrance” means any area used by the occupants of a mixed-income multifamily structure for ingress to or egress from that structure.

(3) “Market-rate housing unit” means any residential dwelling unit that is not an affordable housing unit or a unit occupied by on-site property management staff.

(4) “Mixed-income multifamily structure” means any residential structure with five or more residential dwelling units that includes both affordable housing units and market-rate housing units.