How a free month is written into a South Oceanside lease decides what record exists of that unit's base rent. Under California's Tenant Protection Act, the cap on rent increases is measured from the lowest gross rent charged for the unit in the previous 12 months. Accepted owner-offered concessions are excluded from that calculation, and the statute requires the gross rent and any concessions to be "separately listed and identified" in the lease. A lease that instead shows only a lower stated rent leaves no concession on paper to exclude.
That detail matters more this year than the headline percentage does. San Diego County's cap for increases starting between August 1, 2026 and July 31, 2027 is 8.2%. Oceanside's median rent rose 0.1% in the 12 months through September 2026. The ceiling sits far above what the market is paying. So for an owner of older multifamily in South O, the rent the cap is measured from does most of the limiting.
The cap fell here and rose next door
The California Department of Justice publishes the allowable increase by region each summer. The 2026–27 numbers moved in different directions across the three counties where small-portfolio owners in this market tend to hold property:
| Region | Increases starting 8/1/25–7/31/26 | Increases starting 8/1/26–7/31/27 |
|---|---|---|
| San Diego County, including Oceanside | 8.8% | 8.2% |
| Los Angeles and Orange counties | 8% | 8.7% |
| Riverside and San Bernardino counties | 7.5% | 8.1% |
The formula is 5% plus the change in the local cost of living, with a 10% ceiling. For San Diego County, the statute uses the San Diego-Carlsbad CPI-U. Where April data isn't published for an area, it falls back to March. The Bureau of Labor Statistics' San Diego release of April 10, 2026 reported a 12-month change of 3.2% for March 2026, down from 3.8% for March 2025. Add 5% to each and you get 8.2% and 8.8%.
An owner with units in San Clemente and South Oceanside now works under a lower cap on the San Diego side of the county line. On current market numbers, that difference is close to theoretical. Apartment List's October 2026 report puts Oceanside's median rent at $2,496. That's up 2.9% from January through September 2026 and up 0.1% year over year. The San Diego metro median of $2,291 rose 0.4% over the same 12 months. A landlord who raises a renewal by the full 8.2% in this market is pricing well above where comparable units are leasing.
Free rent is also common across the region. CoStar data reported for August 2026 showed about 30% of San Diego properties offering free rent, up from 20% a year earlier. Flat rents and widespread concessions together are what bring the base-rent rule into play.
The base is set by the lowest rent charged, as written in the lease
Here is the statute's language on what gets left out:
"In determining the lowest gross rental amount pursuant to this section, any rent discounts, incentives, concessions, or credits offered by the owner of such unit of residential real property and accepted by the tenant shall be excluded. The gross per-month rental rate and any owner-offered discounts, incentives, concessions, or credits shall be separately listed and identified in the lease or rental agreement."
That comes from California Civil Code section 1947.12.
Take a hypothetical South O two-bedroom leased for 12 months at an asking rent of $2,500 with one month free. It can be documented two ways:
- Gross rent of $2,500, with a separately listed one-month concession. The lease identifies the concession the statute excludes, so $2,500 is the rent on paper. Measured from $2,500, an 8.2% increase reaches about $2,705.
- Stated rent of about $2,292, the free month averaged across the year. The lease shows $2,292 as the rent charged and identifies no concession. Measured from $2,292, an 8.2% increase reaches about $2,480.
If $2,292 were treated as the base, next year's maximum would sit below the original asking rent, and each later increase would build on that lower starting point. The statute does not spell out how an unlisted concession is handled, so how a particular lease's wording fits the code is a question for counsel. The separate-listing requirement itself is in the code.
For a buyer, the operating history of a building comes down to the concession history on paper. A rent roll that shows effective rents without the lease language behind them can make the legal base look different from what it is.
A below-market tenant is where the cap limits income
The cap applies to rent increases for an existing tenancy. When a new tenancy begins and no prior tenant remains in lawful possession, the owner may set the starting rent freely, and the cap applies only to increases after that. For the same tenant, rent can't be raised in more than two increments in any 12-month period, and the total has to stay within the cap.
In a market growing 0.1% a year, a unit leased near market has nothing to catch up on, so the cap doesn't constrain it. Older South O fourplexes and small apartment buildings tend to include long-held tenancies with rents set years ago. Those are where an 8.2% ceiling limits income.
A hypothetical tenant paying $2,000 in a unit that would lease for about $2,500 today shows the timeline. If the cap stayed at 8.2% each year, which it won't, since the DOJ resets it every August, full increases would bring the rent to:
- About $2,164 after year one
- About $2,341 after year two
- About $2,533 after year three
That's three years of loss-to-lease before the unit reaches today's market rent through renewals. An investor underwriting a value-add acquisition is pricing that runway, and the purchase price should reflect it. The number to model is the distance between each in-place rent and market, set against a cap that changes every year. The cap percentage on its own tells you much less.
The 15-year exemption keeps moving
The cap does not apply to housing that received a certificate of occupancy within the previous 15 years. The window rolls forward. A building whose certificate was issued in October 2011 comes under the cap around now, in October 2026. Each later month moves another set of newer buildings into coverage.
Underwriting a newer South Oceanside building as uncapped is only accurate up to a date that can be calculated in advance. The certificate of occupancy date sets when the cap starts to apply, and it belongs in the pro forma as a fixed date in the hold period.
Some properties are exempt for other reasons. Individually alienable units such as single-family homes and condos can be exempt when the owner is not a REIT, a corporation, or an LLC with a corporate member, and the tenant has received a specific written notice set out in the statute. An owner-occupied two-unit structure can also qualify, provided neither unit is an ADU or JADU.
Oceanside has no local layer, and the City's page shows last year's number
Oceanside follows the state framework and has no local cap on top of it. According to a City of Oceanside staff report dated June 17, 2026, the City Council voted 2–3 on September 3, 2025 not to move forward with a local rent stabilization program. On September 17, 2025, it voted 2–3 against adopting Chapter 14D, "Residential Tenant Protections," which would have gone beyond state law.
That same report shows the question is still active. On January 27, 2026, the Housing Commission voted 6-0-0 to recommend a work plan that included pursuing a local rent cap below the state level. Staff recommended changing that goal to advocating for state legislation, consistent with the Council's September 2025 votes. The latest official status we found is from that June 2026 report. Anyone holding Oceanside rentals over several years should keep watching the Council agenda.
A smaller point affects day-to-day operations. The City's landlord-tenant page still lists 8.8% as the allowable increase, labeled for August 1, 2025 through July 31, 2026. For increases taking effect now, the DOJ chart lists 8.2%. Tenants and owners checking the City page will find a figure that no longer applies.
Quick answers
Does the 8.2% cap apply to a renewal notice sent in October 2026? The DOJ chart ties the figure to when the increase starts. An increase starting between August 1, 2026 and July 31, 2027 on a covered San Diego County unit falls under 8.2%.
Is the cap based on the current rent or the previous rent? It's based on the lowest gross rent charged at any point in the 12 months before the increase takes effect, with accepted owner-offered concessions excluded. The statute also requires those concessions to be listed separately in the lease.
Why is Orange County's cap higher than San Diego County's this year? Each region's figure follows its own BLS price index. The Los Angeles-area index that covers Orange County produced 8.7%, and San Diego's produced 8.2%.
If you own or are pricing older multifamily in South Oceanside, the useful numbers are each unit's legal base rent, its gap to market, and the building's certificate of occupancy date. OC Investments & Management works through those on the rent rolls we underwrite and on the leases we write for the buildings we manage, from San Clemente down to South O. Schedule a Free Investment Consultation and bring your current leases.
This article is general information, not legal, tax or financial advice. Consult a qualified professional about your situation.
