Count the increase over twelve months, not just this one. That single habit decides which notice period you owe, and it is the step most often skipped.
California’s rule is in Civil Code § 827(b). It applies to residential tenancies that run week to week, month to month, or any period shorter than a month. If the lease is a fixed term, the lease sets the rent until the term ends, and its own terms control whether anything can change before then.
The two periods
At least 30 days when the increase is 10 percent or less of the rent charged to that tenant at any time in the 12 months before the effective date. That test counts this increase together with any other increase in the same 12 months (§ 827(b)(2)).
At least 90 days when the increase, alone or combined with others in the prior 12 months, is more than 10 percent (§ 827(b)(3)(A)).
One exception. If the rent changes because a statute or regulation requires the tenant’s income or household to be recertified, as in many subsidized programs, 30 days is enough regardless of the size (§ 827(b)(3)(B)).
Here is how the combining works. A tenant at $2,000 got a $100 increase in February. You want another $150 in December. Each one on its own is under 10 percent. Together they are $250 on a base of $2,000, which is 12.5 percent, so the December increase needs 90 days.
Why the 90-day rule still matters under AB 1482
For a unit covered by the statewide cap, an increase over 10 percent in a year cannot happen legally, so the 30-day period is the one you will use. The 90-day rule bites on units the cap does not reach: an exempt single-family home with the right lease clause, an owner-occupied duplex, or a building still inside its 15-year new construction window. The exemptions are covered in is my property exempt from AB 1482.
Delivery adds days
The statute allows two ways to deliver the notice: hand it to the tenant personally, or mail it under Code of Civil Procedure § 1013 (§ 827(b)(1)). Mailing extends the notice period by five calendar days when both addresses are in California (Code Civ. Proc. § 1013(a)).
A worked calendar, for a new rent that starts December 1:
| Delivery | Notice period | Latest date to deliver |
|---|---|---|
| By hand | 30 days | November 1 |
| By mail, in California | 30 days plus 5 | October 27 |
| By hand | 90 days | September 2 |
| By mail, in California | 90 days plus 5 | August 28 |
Those are the last possible days. Most landlords who do this for long enough stop cutting it close and send the notice a week earlier than the table says. A tenant who claims the notice arrived late is a dispute you avoid entirely with a few days of margin.
Keep proof of the delivery date. For hand delivery, a dated note signed by whoever delivered it. For mail, the proof of service with the date of deposit.
When a longer period applies
Section 827 sets a floor. If another statute, a regulation, a recorded regulatory agreement, or the lease itself requires more notice, the longer period governs (§ 827(c)). Check the lease before you assume 30 days. Some leases promise 60.
Cities add their own paperwork
Local ordinances sit on top of the state notice rule, and they tend to add documents rather than days.
- Oakland requires a copy of the Rent Adjustment Program notice with every increase on a covered unit, at least 30 days’ written notice, and a current business tax certificate. A unit that is not registered with the program cannot be increased at all.
- Los Angeles limits a unit under the Rent Stabilization Ordinance to one increase every 12 months, at the percentage the city publishes. See the Los Angeles RSO guide.
- San Jose limits apartments under its Apartment Rent Ordinance to one 5 percent increase in 12 months.
The California rent control city list covers the rest of the cities with their own rules.
What the notice should say
The statute sets the timing and the delivery method. The notice itself should state the current rent, the new rent, and the date the new rent takes effect, in plain numbers. Set the effective date on the first day of a rental period so nobody has to argue about a split month.
Before any of that, make sure the amount is legal. How to calculate a legal rent increase in California works through the cap step by step, and the AB 1482 rent increase limits page covers who the cap reaches.
This is general information, not legal advice. Rules change and local ordinances vary. Confirm current requirements with your city, county, or an attorney before you act.
After the notice goes out
Put the new amount on the lease record with its effective date the same day you send the notice. Rent payments in LeaseRooster bill from the lease record, so the first invoice after the effective date carries the new rent and autopay follows it. Forgetting that step is how a landlord serves a perfect notice and then bills the old rent for three months.