Cal. Civ. Code § 2924o

(a) On and after January 1, 2023, in the case of any real property purchased pursuant to Section 2924m by an eligible bidder described in subparagraphs (C) to (G), inclusive, of paragraph (3) of subdivision (a) of that section, the property shall be subject to a recorded covenant that ensures the property shall be sold at an affordable housing cost, as defined in Section 50052.5 of the Health and Safety Code, or rented at an affordable rent, as defined in Section 50053 of the Health and Safety Code, for lower income households for 30 years from the date the trustee’s deed is issued, or a greater period of time if any of the following apply:
1. (1) The terms of a federal, state, or local grant, tax credit, or other source of project financing funding the purchase or maintenance of the property by an eligible bidder require a longer term.
2. (2) The property becomes subject to a contract as described in paragraph (11) of subdivision (a) of Section 402.1 of the Revenue and Taxation Code.
(b) Tenants, if any, of a property purchased pursuant to Section 2924m by an eligible bidder described in subparagraphs (C) to (G), inclusive, of paragraph (3) of subdivision (a) of that section may exercise any rights available at equity or in law, including, without limitation, to defend an unlawful detainer or institute an action to enforce this section.
(c) For purposes of this section, “lower income households” has the same meaning as described in Section 50079.5 of the Health and Safety Code.
(d) This section shall remain in effect only until January 1, 2031, and as of that date is repealed, unless a later enacted statute that is enacted before January 1, 2031, deletes or extends that date.