Since 2020, most California apartments have had a statewide rent ceiling, and a striking number of increases violate it — because landlords bet tenants never run the formula. The formula lives in Civil Code §1947.12: over any 12-month period, gross rent may not rise more than 5% plus the regional CPI change, or 10%, whichever is lower, with no more than two increases in the period summing within the cap.
Who’s covered: most apartments and multifamily units older than 15 years (a rolling window). Exemptions include newer construction, most single-family homes and condos — but only if the owner is not a corporation or REIT and the required exemption language appears in the lease — plus duplexes where the owner occupies one unit. Cities with stricter local rent control (Los Angeles, San Francisco, Santa Ana, and others) apply their own lower caps; AB 1482 is the floor of protection, not the ceiling.
Running the numbers: the applicable CPI is the regional April-over-April figure published for these purposes — the Attorney General maintains guidance and current percentages. In recent years the allowable statewide increase has landed in the 8–9% range for most regions; any notice above 10% on a covered unit is per se unlawful.
Notice rules travel with it. Civil Code §827 requires 30 days’ written notice for increases of 10% or less and 90 days’ for larger increases (only possible on exempt units) — served properly, not texted.
If the increase is over-cap: the demand for rent above the lawful ceiling is void as to the excess. Respond in writing: cite §1947.12, show the math, tender the lawful amount. Overpaid excess is recoverable, and the Tenant Protection Act’s remedies were strengthened effective 2024 (§1947.12(k)) to include actual damages, attorney’s fees, and treble damages for willful violations, with Attorney General and city-attorney enforcement authority.
An unlawful increase also can’t support an eviction for nonpayment of the unlawful portion. Five minutes of arithmetic against a public CPI number — that’s the entire defense, and most tenants never do it.
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The Hedge 