The statewide formula
For units AB 1482 covers, Civil Code § 1947.12 limits annual increases to 5% plus local CPI, never more than 10%. The cap is statewide. A city ordinance can be stricter. It cannot authorize a larger jump on a covered unit.
What is not covered
Single-family homes and condos owned by a natural person who is not a REIT or corporation, newer construction, and some deed-restricted affordable housing sit outside the statewide cap if you give the required notice. Guessing that a tenancy is exempt — then serving a 12% increase — is how tenants win petitions.
Just cause is the other half
After a tenant has been in place long enough, Civil Code § 1946.2 requires a just-cause reason to terminate. A rent increase is not a termination. Ending a tenancy to dodge the cap, or stacking notices, is how AB 1482 and local rent-board rules combine against you.
Put the math on the notice
State the current rent, the new rent, the effective date, and which statute or ordinance you think applies. If you are wrong about coverage, the increase is the defect. Generate a clean notice; do not reuse last year's Word file with a new number.