Cal. Gov't Code § 12955.1.1

For purposes of Section 12955.1, the following definitions shall apply:
(a) “Covered multifamily dwellings” means both of the following:
(1) Buildings that consist of at least four condominium dwelling units or at least three rental apartment dwelling units if the buildings have at least one elevator. For purposes of this definition, dwelling units within a single structure separated by firewalls do not constitute separate
buildings.
(2) The ground floor dwelling units in buildings that consist of at least four condominium dwelling units or at least three rental apartment dwelling units if the buildings do not have an elevator. For purposes of this definition, dwelling units within a single structure separated by firewalls do not constitute separate buildings.
(b) “Multistory dwelling unit” means a condominium dwelling unit or rental apartment with finished living space on one floor and the floor immediately above or below it or, if applicable, the floors immediately above and below it.