Cal. Health & Safety Code § 33334.5

Every redevelopment plan adopted or amended to expand the project area after January 1, 1977, shall contain a provision that whenever dwelling units housing persons and families of low or moderate income are destroyed or removed from the low- and moderate-income housing market as part of a redevelopment project, the agency shall, within four years of such destruction or removal, rehabilitate, develop, or construct, or cause to be rehabilitated, developed, or constructed, for rental or sale to persons and families of low or moderate income an equal number of replacement dwelling units at affordable housing costs, as defined by Section 50052.5, within the project area or within the territorial jurisdiction of the agency, in accordance with all of the provisions of Sections 33413 and 33413.5.