How many days notice do you actually owe before a California rent increase?

Published July 25, 2026

Civil Code 827 sets two different notice windows for a rent increase, and picking the wrong one is the most common way self managing owners invalidate an otherwise legal increase.

If you are raising rent yourself, the notice period is not one number. California Civil Code 827 gives you 30 days if the increase is 10 percent or less of what the tenant paid over the past 12 months, and 90 days if it is more than that. Get the bucket wrong, or serve the notice incorrectly, and the increase does not hold.

The two windows, and why owners mix them up

Civil Code section 827 splits every rent increase into one of two lanes. If the total increase, measured against what the tenant was charged at any point in the 12 months before the effective date, comes to 10 percent or less, you owe at least 30 days notice before the increase takes effect. If it comes to more than 10 percent, you owe at least 90 days.

The mistake I see most is owners assuming 90 days only applies to a single jump over 10 percent, then serving a smaller increase in month one and another smaller one in month four, each under 10 percent on its own, thinking that dodges the longer notice period. It does not. The statute looks at the cumulative increase over the trailing 12 months, not just the notice you happen to be serving today. If your tenant paid $2,000 in January and you have already raised them once to $2,150 by June, and now you want to go to $2,250 in August, you have to add up everything charged over the prior 12 months against the new number. Stack enough smaller increases and you cross 10 percent even though no single notice looks like it.

Calculating which bucket you are in

Before you write anything, pull the rent roll for that unit going back 12 months from your intended effective date. Find the lowest and highest amounts charged in that window, then compare your new proposed rent to what the tenant was actually paying. The math is simple percentage change: (new rent minus old rent) divided by old rent. If that comes out to 10 percent or under, you are in the 30 day lane. If it is over 10 percent, you are in the 90 day lane.

Two things trip owners up here. First, "12 months" runs backward from the effective date of the new increase, not from the date you happen to be writing the notice. Second, if you have given the tenant more than one increase in that 12 month window, California looks at the increase as compared to the rent in effect at any point during those 12 months, which usually means comparing against the lowest rent charged in that period, not just the most recent one. If you are close to the line, this is exactly the kind of edge case worth a five minute call with a licensed professional before you serve anything, because guessing wrong here is what unwinds an increase in front of a judge.

Serving the notice correctly

Civil Code 827 recognizes two delivery methods: personal delivery to the tenant, or mail following the procedure in Code of Civil Procedure section 1013. Both are valid. Which one you pick changes your math.

Personal delivery is the cleanest. Hand the written notice to the tenant, or to another adult at the unit if the tenant is not home, and the notice period starts running from that date. Keep a dated, signed proof of service or have a witness present, because if the increase is ever challenged, you will need to show exactly when the clock started.

Mail is more common for self managing owners because it does not require a face to face handoff, but it comes with a catch: under Code of Civil Procedure 1013, mailing within California adds extra days to the notice period on top of the 30 or 90 days already required. Owners who mail a notice and count the 30 or 90 days from the postmark, without adding the mail extension, are the single most common cause of an invalidated increase I have seen. If you mail, build in the cushion rather than cutting the notice to the exact minimum.

Whichever method you use, the notice itself needs to be in writing, state the new rent amount, and state the effective date. A verbal heads up, a text message alone, or a vague "rent is going up soon" conversation does not satisfy the statute.

Calculating the effective date correctly

Once you know your lane and your delivery method, count forward. The effective date is the day the increase actually starts, and the full 30 or 90 days has to have run before that date, not up to it. If you serve a 30 day notice by personal delivery on August 1, the earliest lawful effective date lands right around August 31, and I would not cut it that close. Count the full period and then add one more day past it if you want the cleanest possible position, since disputes tend to turn on whether a landlord came in one day short.

If you mail the notice, add the Code of Civil Procedure 1013 mail extension on top of the 30 or 90 days before you land on your effective date. Write the effective date directly into the notice itself rather than leaving the tenant to do the math, and build a little slack into your calendar so a mail delay or a miscount does not put you under the line.

Common mistakes that invalidate a notice

The pattern I see most with self managing owners is picking the 30 day lane by looking only at this one increase, missing that an earlier increase in the same 12 months pushes the cumulative total over 10 percent. The second most common mistake is mailing a notice and counting the notice period from the day it was mailed instead of adding the mail extension. The third is leaving the effective date vague or undercounting by a day or two, which is an easy fix and a cheap way to protect the increase from a challenge later.

Common questions

Do I count calendar days or business days for the 30 or 90 day notice?

Civil Code 827 uses calendar days, not business days. Weekends and holidays count toward the total.

What if my tenant is on a fixed term lease, not month to month?

A rent increase generally cannot take effect until the current lease term ends, regardless of the notice period. Review your lease's renewal terms and confirm the timing with a licensed professional before serving any increase notice to a tenant still under a fixed term.

Does a local rent control ordinance change these numbers?

It can. Some California cities layer additional notice or percentage rules on top of state law. Confirm whether your property sits inside a local rent control jurisdiction before relying on the state 30 or 90 day figures alone.

Last verified: July 25, 2026. This is general information for property owners, not legal advice. Confirm your specific situation with a licensed attorney.

Kellie

Schofield Properties

323 Richmond Street, El Segundo, CA 90245

Topics: self-management, rent-increase, landlord-guide

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