The default: frequency usually isn't limited unless a specific law says so
For a month-to-month tenancy, a landlord can generally raise rent as often as they provide the required advance notice each time, unless a specific state or local law limits the frequency. For a fixed-term lease, rent generally can't change at all until the lease renews or converts to month-to-month, so the lease term itself is what limits frequency in the meantime — see can my landlord raise rent during my lease term.
Three states that limit increases within a 12-month period
California, Oregon and Washington each go further than just requiring notice. California and Oregon limit how often an existing tenant's rent can go up; Washington limits how much it can go up across the year, which has the same practical effect on repeated increases.
- California Civil Code § 1947.12(a)(2): if the same tenant stays in the unit over any 12-month period, "the gross rental rate for the unit... shall not be increased in more than two increments over that 12-month period" — so up to two smaller increases are allowed within the year, as long as their combined total doesn't exceed the overall percentage cap.
- Oregon ORS 90.323(2)(c): a landlord may not increase rent "more than once in any 12-month period," on top of requiring 90 days' notice and barring any increase during the first year of a tenancy.
- Washington RCW 59.18.700(1)(a): a landlord may not raise rent "during any 12-month period of the tenancy" by more than the capped amount — read together with the rest of the statute, an existing tenant is protected from repeated increases that would add up to more than the annual cap within that same 12-month window.
Notice that California explicitly allows splitting the annual increase into two smaller increases, while Oregon flatly limits it to one increase per 12 months — a real difference between two states that both cap the same general idea.
A realistic example
Say you're a month-to-month tenant in Oregon paying $1,400 a month, and your landlord raises the rent in March, then tries to raise it again in July — five months later. Under ORS 90.323, that second increase within the same 12-month window is exactly what the statute prohibits, regardless of whether the two increases combined stay under the annual percentage cap, because Oregon limits the count of increases, not just their size. A tenant in California facing that same pair of increases would be in a different position, since California explicitly allows up to two increases within a 12-month period as long as they add up to no more than the overall cap.
Why landlords sometimes raise rent in smaller, more frequent steps
Some landlords prefer smaller, more frequent increases to move rent toward market rates without one large jump that risks losing a tenant. Where that approach is legal, it's a business choice, not a violation — the only question is whether your state's law allows more than one increase in the relevant window, and if so, how many and under what combined limit.
What this means if you're not in one of those three states
Outside a law like these, "how often" is mostly a function of your lease type and your landlord's willingness to send repeated notices, not a fixed rule. A landlord technically could send a new 30-day notice every month for a month-to-month tenant in a state without a frequency cap, though doing so repeatedly could raise other issues — including whether it starts to look like retaliation if it follows a complaint, or a bad-faith attempt to force you out.
Local rent-control ordinances in various cities and counties may also limit frequency even where the state itself doesn't — check whether one applies in your area before assuming there's no limit at all.
What to do
Check whether your state has a frequency rule like California's, Oregon's, or Washington's, or whether a local ordinance applies where you live — the rent control hub is the place to start. Track every rent-increase notice you receive with its date and amount, since a second increase within a short window is exactly what you'd need to document to challenge one that violates a frequency limit. Honestkey™ reviews your uploaded lease's rent terms and notice history so you can see whether a new increase fits the pattern your state and lease actually allow.