In Sunnyvale, the rent increase limit is set by California’s Tenant Protection Act (AB 1482): most landlords cannot raise your rent by more than 5% plus the local change in the Consumer Price Index in any 12-month period, and never by more than 10% total. For increases taking effect on or after August 1, 2025, the Santa Clara County cap is approximately 7.7%. Sunnyvale does not have its own local rent control ordinance, so the state formula governs how much your rent can go up.
How the 5% Plus CPI Cap Is Calculated
California Civil Code Section 1947.12 limits annual rent increases on covered units to 5% plus the annual percentage change in the cost of living, with a hard ceiling of 10%. Both numbers are measured against the lowest rent charged for your unit at any point during the prior 12 months, not whatever you happen to be paying when the notice arrives.1California Legislative Information. California Code CIV 1947.12 – Rent Increase Limitations
The math is straightforward. If you pay $3,000 a month and the applicable CPI change is 2.7%, the maximum increase is 7.7%, or $231, bringing your new rent to $3,231. If inflation were high enough that 5% plus CPI came out to 11%, the 10% ceiling would still cap your increase at $300.
Which CPI applies to Sunnyvale matters. Santa Clara County sits outside the San Francisco-Oakland-Hayward metropolitan CPI area, so the calculation uses the California statewide CPI rather than the Bay Area index. The two produce different numbers, and using the wrong one gives the wrong cap.
The measurement period also depends on timing. For increases that take effect before August 1, the CPI change is measured from April two years before to April of the prior year. For increases on or after August 1, it runs from April of the prior year to April of the current year, with the result rounded to the nearest tenth of a percent.1California Legislative Information. California Code CIV 1947.12 – Rent Increase Limitations That split schedule is why the allowable cap can change on August 1 each year.
AB 1482 took effect January 1, 2020, and is currently set to expire January 1, 2030.
Does the Cap Apply to Your Unit?
Several categories of housing are exempt from AB 1482’s rent cap:
- Housing issued a certificate of occupancy within the previous 15 years. This is a rolling window, so a building constructed in 2012 came under the cap in 2027.
- Single-family homes and condominiums, if the owner is not a corporation, a real estate investment trust, or an LLC with a corporate member — and only if the landlord has given the tenant the specific written exemption notice required by the statute.
- Owner-occupied duplexes, where the owner has lived in one of the two units as a principal residence since the tenancy began. Neither unit can be an accessory dwelling unit.
The single-family home exemption is easy for landlords to lose. The statute requires a written notice using prescribed language, declaring that the property is not subject to the rent limits of Section 1947.12 or the just cause requirements of Section 1946.2, and that the owner is not a corporation, REIT, or corporate-member LLC.1California Legislative Information. California Code CIV 1947.12 – Rent Increase Limitations For tenancies that started or renewed on or after July 1, 2020, no notice means no exemption, regardless of who owns the property.
Notice Your Landlord Must Give You
Civil Code Section 827 controls how far in advance you must be told about a rent increase, and the number depends on the size of the increase over the prior 12 months:
- If the increase, combined with any other increases in the past 12 months, is 10% or less, you get at least 30 days’ written notice.
- If the cumulative increase is more than 10%, you get at least 90 days’ written notice.
Cumulative is the key word. If your landlord raised rent 6% four months ago and now proposes another 5%, that is 11% within 12 months and triggers the 90-day rule. The notice must be delivered in person or by mail following the Code of Civil Procedure.2California Legislative Information. California Civil Code Section 827 A notice that falls short is not enforceable, and the landlord cannot collect the higher rent until proper notice has been given and the full period has run.
Sunnyvale’s Added Protections for Newer Buildings
Sunnyvale has no local rent cap of its own, but Sunnyvale Municipal Code Chapter 19.71 extends tenant protections past what state law provides. The biggest change is that Sunnyvale applies just cause eviction protections to buildings issued certificates of occupancy within the previous 15 years, which state law otherwise exempts from both the rent cap and the just cause requirement.3City of Sunnyvale, CA. City of Sunnyvale Code of Ordinances – Chapter 19.71 Residential Tenant Protections Programs Chapter 19.71 also sets higher relocation assistance amounts than state law and requires minimum lease terms for covered tenancies.
What this means in practice: if you live in a Sunnyvale building less than 15 years old, your landlord can still raise your rent without a percentage cap, but they cannot end your tenancy without a legally recognized reason. That matters because, without just cause protection, a landlord could simply terminate a tenancy and re-list the unit at a higher price to sidestep any rent limit.
What to Do If the Increase Exceeds the Cap
A landlord who charges rent above the AB 1482 maximum faces real consequences. Section 1947.12(k) lets a tenant sue to recover the full amount overpaid, and the court can award reasonable attorney’s fees. If the landlord acted willfully or with fraud, damages can be tripled.1California Legislative Information. California Code CIV 1947.12 – Rent Increase Limitations
The California Attorney General and the local city attorney or county counsel can also enforce the cap and seek injunctive relief. Courts presume a tenant suffers irreparable harm from a rent cap violation, which makes it easier to get an order stopping the landlord. You have three years from the date of the violation to file suit.
If you think your increase is too high, start by pulling together the written notice, your rent payment history for the past 12 months, and the applicable CPI figure for the month your increase takes effect. From there, a tenant rights organization or attorney can confirm whether the number is lawful and what remedy fits.
Mobile Home Space Rent Is Handled Differently
If you own a mobile home and rent space in a Sunnyvale park, AB 1482 is not the governing rule. Sunnyvale does not have a mobile home rent stabilization ordinance; instead, the city relies on a Memorandum of Understanding between residents and park owners to set annual space rent increases.4City of Sunnyvale. Mobile Home Parks An MOU is a voluntary agreement rather than a binding ordinance, so it carries less enforcement weight than formal rent control. Residents with disputes are directed to Project Sentinel, a nonprofit dispute resolution service.