Cal. Gov't Code § 12955.9

(a) The provisions of this part relating to discrimination on the basis of familial status shall not apply to housing for older persons.
(b) As used in this section, “housing for older persons” means any of the following:
(1) Housing provided under any state or federal program that the Secretary of Housing and Urban Development determines is specifically designed and operated to assist elderly persons, as defined in the state or federal program.
(2) Housing that meets the standards for senior housing in Sections 51.2,
51.3, and 51.4 of the Civil Code, except to the extent that those standards violate the prohibition of familial status discrimination in the federal Fair Housing Amendments Act of 1988 (Public Law 100-430) and implementing regulations.
(3) Mobilehome parks that meet the standards for “housing for older persons” as defined in the federal Fair Housing Act, as amended by Public Law 104-76, and implementing regulations.
(c) For purposes of this section, the burden of proof shall be on the owner to prove that the housing qualifies as housing for older persons.