Mid-Year Check: California's Rent-Cap Math Under AB 1482

For most California residential rentals covered by the Tenant Protection Act of 2019 (AB 1482), there is a hard ceiling on annual rent increases. The number is not a flat 5%; it floats with inflation. A surprising number of landlords either guess at the cap or rely on a property-management vendor's number without checking the calculation. Both are risk.

This post walks through the math, where the inputs come from, and what to keep in the file.

The general rule

For covered units, AB 1482 caps any twelve-month rent increase at the lesser of:

• 5% plus the percentage change in the regional Consumer Price Index for the prior April-to-April period, or
• 10%

Two increases per twelve months are allowed, but they cannot exceed the cap in the aggregate. The "regional" CPI means the CPI for the metropolitan area in which the property is located — not the statewide figure — and California publishes the inputs that landlords are expected to use.

A worked example: if the relevant regional CPI rose 3.4% over the prior April-to-April window, the cap for the next twelve months would be 5% + 3.4% = 8.4%, well under the 10% absolute ceiling. If CPI rose 6%, the cap would clip at 10% rather than 11%.

When the cap "resets"

The relevant CPI is the April-to-April change, but the cap applies to any twelve-month rolling period for the tenancy in question, anchored to the date of the increase. Two practical implications:

• An increase taken in early summer of one year may use a different cap than one taken in late spring of the next, because the CPI input has been re-published in the meantime.
• The cap follows the unit, not the calendar. There is no "January 1 reset"; the test is whether the increase, taken now, exceeds the lesser of (5% + current CPI) or 10% over any twelve-month period for that tenancy.

Both points come up regularly in disputes when a landlord has bumped rent twice in a single twelve-month window without reconciling the aggregate to the cap.

What is exempt — and the trap that comes with it

Several categories of housing are not covered by AB 1482, including, in general terms:

• Single-family homes and condominiums where the owner is a natural person (not a corporation, REIT, or LLC with a corporate member) and that ownership status is communicated to the tenant in the lease, in the form required by the statute
• Properties with a certificate of occupancy issued within the last fifteen years (rolling)
• Deed-restricted affordable housing
• Housing accommodations subject to a more restrictive local rent-control ordinance (those local rules apply instead)

The trap is the natural-person exemption. It only applies if the lease contains the specific written notice required by Civil Code § 1947.12. A lease that quietly assumes the unit is exempt without delivering the statutory notice has not exempted itself, and the cap may still apply. The firm sees this gap regularly in pre-litigation lease reviews.

Local ordinances also matter. Several California cities — Los Angeles, San Francisco, Berkeley, Oakland, Santa Monica, San Jose, and others — have their own rent-control schemes that are tighter than AB 1482 and that may also impose just-cause requirements separate from AB 1482's. Where local rules apply, they generally control the rent-increase math for that jurisdiction.

Documentation worth keeping

For each covered unit, a landlord file should contain (at a minimum):

• The lease itself, including any AB 1482 exemption notice
• Any addenda extending or modifying rent terms
• A short calculation memo for each rent increase: date, base rent, prior increases in the look-back period, the CPI input used (with source and date), the resulting cap, and the noticed increase
• The rent-increase notice itself, with proof of service

A clean memo is a better defense than a clever lawyer if a tenant later disputes the increase in small claims or as a defense to an unlawful-detainer.

Practical takeaway

The AB 1482 cap is a moving target, not a fixed percentage, and the CPI inputs change every spring. Landlords should re-run the cap before issuing a rent-increase notice, document the math, and confirm whether any local ordinance imposes a stricter ceiling. A lease that relies on a stale spreadsheet from two years ago is the lease that gets caught short.

If you would like the firm to review a current lease, run the cap calculation on a planned increase, or refresh your forms to address current California requirements, please reach out.

This article is general information and not legal advice. The CPI inputs used in the AB 1482 calculation change annually and the surrounding statutes can be amended; specific situations need specific review.