Ontario, CA Rental Property Rules: Rent Control (2026)

Civil Code - CIV. 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. (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. (b) For a new tenancy in which no tenant from the prior tenancy remains in lawful possession of the residential real property, the owner may establish the initial rental rate not subject to subdivision (a). Subdivision (a) is only applicable to subsequent increases after that initial rental rate has been established. (d) This section shall not apply to the following residential real properties: (1) Housing restricted by deed, regulatory restriction contained in an agreement with a government agency, or other recorded document as affordable housing... (4) Housing that has been issued a certificate of occupancy within the previous 15 years, unless the housing is a mobilehome.