Cal. Civ. Code § 1947.12

(a) (1) Subject to subdivision (b), an owner of residential real property shall not, over the course of any 12-month period, increase the gross rental rate for a dwelling or a unit more than 5 percent plus the percentage change in the cost of living, or 10 percent, whichever is lower, of the lowest gross rental rate charged for that dwelling or unit at any time during the 12 months prior to the effective date of the increase. In determining the lowest gross rental amount pursuant to this section, any rent discounts, incentives, concessions, or credits offered by the owner of such unit of residential real property and accepted by the tenant shall be excluded. The gross per-month rental rate and any owner-offered discounts, incentives, concessions, or credits shall be separately listed and identified in the lease or rental agreement or any amendments to an existing lease or rental agreement.

(2) If the same tenant remains in occupancy of a unit of residential real property over any 12-month period, the gross rental rate for the unit of residential real property shall not be increased in more than two increments over that 12-month period, subject to the other restrictions of this subdivision governing gross rental rate increase.

(3) The rental rate increase cap shall be calculated based on the rental rate in effect at the beginning of the 12-month period, and no subsequent increases or decreases during the 12-month period shall reset the calculation.

(b) For any residential real property, except as provided in subdivision (c), an owner may establish the initial rental rate for a dwelling or unit in any amount upon the initial rental of the dwelling or unit and upon the termination of a tenancy.

(c) This section shall not apply to the following types of residential real property:
(1) Housing that has been issued a certificate of occupancy within the previous 15 years.
(2) Residential real property alienated by government agencies under programs to preserve and maintain affordable housing.
(3) Dormitories and residential facilities operated by institutions of higher education for students.
(4) Residential real property subject to a local rent control or rent stabilization ordinance.
(5) Single-family owner-occupied residences, including a residence in which the owner-occupant rents or leases no more than two units or bedrooms.
(6) A duplex in which the owner occupied one of the units as the owner's principal place of residence at the beginning of the tenancy.
(7) Housing restricted by deed, regulatory restriction, or other recorded document as affordable housing for persons and families of very low, low, or moderate income.