California Code, Government Code - GOV § 54222.5

An entity proposing to use the surplus land for developing low- and moderate-income housing shall agree to make available not less than 25 percent of the total number of units developed on the parcels at affordable housing cost, as defined in Section 50052.5 of the Health and Safety Code, or affordable rent, as defined in Section 50053 of the Health and Safety Code, to lower income households, as defined in Section 50079.5 of the Health and Safety Code.  Rental units shall remain affordable to, and occupied by, lower income households for a minimum of 55 years for rental housing, 45 years for ownership housing, and 50 years for rental or ownership housing located on tribal trust lands.  The initial occupants of all ownership units shall be lower income households, and the units shall be subject to an equity sharing agreement consistent with paragraph (2) of subdivision (c) of Section 65915.  These requirements shall be contained in a covenant or restriction recorded against the surplus land at the time of sale, that shall run with the land and shall be enforceable, against any owner who violates a covenant or restriction and each successor in interest who continues the violation, by any of the following: