Updated October 6, 2026
The Rent Stabilization Ordinance (RSO) is the City of Los Angeles law that limits how much an owner can raise rent each year on most apartments built on or before October 1, 1978, and that restricts evictions to specific legal reasons. It covers roughly 118,000 properties across the city, according to the Los Angeles Housing Department (LAHD), and it applies only inside LA City limits.
Searches for "California RSO" almost always mean this ordinance. There is no statewide RSO. The state-level floor is AB 1482, the California Tenant Protection Act, and unincorporated LA County has its own law, the RSTPO.
A rental unit is covered when the property was first built on or before October 1, 1978 and it is an apartment, condominium, townhome, duplex, two or more houses on one parcel, a room in a hotel or rooming house rented to the same tenant for 30 or more consecutive days, a residential unit attached to a commercial building, or an ADU or JADU. Units built after July 15, 2007 to replace demolished RSO units can be covered too.
Not covered: a single-family home that is the only residence on its parcel, most buildings built after 1978, and affordable or luxury units LAHD has formally exempted.
Here is the part most owners have never heard: the 1978 line is drawn by the first certificate of occupancy, but LAHD's own registration bulletin says a building without a certificate on file still falls under the RSO if permits or other evidence show it was used as housing before October 1, 1978. The paper trail decides, not the date on the certificate and not how new the building looks.
LAHD's bulletin sets the annual increase between 1% and 4%, based on the average Consumer Price Index for the 12 months ending each September 30. The figure is not cumulative and not retroactive. For July 1, 2026 through June 30, 2027, it is 3%. LAHD's chronology shows 4% for July 2024 through June 2025 and 3% for July 2025 through June 2026.
Since February 2, 2026, an owner cannot add a utility percentage to the annual increase, and cannot raise rent when a dependent joins the tenancy. A non-dependent additional tenant still allows a 10% increase, with notice inside 60 days of learning about the person.
The cap has release valves: capital improvement, primary renovation, rehabilitation, seismic retrofit, and "just and reasonable" applications, all approved by LAHD. For the last one, see the hardship adjustment. The 2026 changes to the ordinance are covered in what the RSO rewrite means for your building.
A buyer underwrites the rents the ordinance lets them collect, not the rents the neighborhood would pay. Rent resets to any amount only when a unit turns over for a listed reason: the tenant moves out voluntarily, is evicted for nonpayment or an uncured lease violation, or signs a filed "cash for keys" agreement. That reset is why tenant buyouts exist, and why the gap between a unit's rent and its market rent shows up in every offer. The full pricing mechanics are in how rent control affects your sale price.
Now the uncomfortable part. Registration is part of what you are selling. LAHD's bulletin states that an owner cannot legally demand or accept rent on an RSO unit without a valid registration, and that unpaid registration or inspection fees can be raised by a tenant as a defense to eviction. A buyer's attorney will ask for the registration history in due diligence, and a gap makes every rent on the roll a question. Whether a lapse affects a particular rent roll is a question for your attorney.
LAHD says to enter the address in ZIMAS (zimas.lacity.org), open the Housing tab, and read the RSO status. For a building you plan to buy or sell, also pull the certificate of occupancy and permit history, since the permit record can override a missing certificate. Confirm anything that matters with LAHD at (866) 557-7368.
The cap gets the attention, but the paperwork is what a buyer actually prices. A building with clean registration, a documented certificate date, and rents that match the file sells without a discount for doubt. One without them sells for what the buyer's attorney is willing to risk.
What is RSO in Los Angeles?
The Rent Stabilization Ordinance, the City of Los Angeles law that caps annual rent increases and limits evictions to listed reasons on most apartments built on or before October 1, 1978. LAHD administers it.
Is there a California RSO?
No. RSO belongs to the City of Los Angeles. Statewide, the rent cap and eviction rules come from AB 1482, and other cities and LA County have their own ordinances.
What does RSO status mean?
It tells you whether LAHD records a property as covered by the ordinance. If it is, rent increases are capped, evictions need a listed reason, and the units must be registered each year.
How much can I raise rent on an RSO unit in 2026–2027?
LAHD lists 3% for July 1, 2026 through June 30, 2027. The percentage is reset each July within a 1% to 4% range based on the Consumer Price Index.
What is the RSO fee?
The annual registration fee is $38.75 per rental unit. You can pass half to the tenant as a $1.61 monthly surcharge with 30 days' written notice. A separate inspection fee also applies; LAHD's bulletin lists $67.94 per unit, half of which can be passed on.
How do I know if my building is RSO?
Look up the address in ZIMAS and read the RSO status under the Housing tab. Then check the certificate of occupancy date and permit history. A building built before October 1, 1978 is presumed covered unless it qualifies for an exemption.
What does it mean when a building is "RSO"?
Buyers read it as capped income. Rents on existing tenancies can only rise by the annual percentage, so the building's value tracks the rent roll in place, plus whatever turnover lets you reset.
Does the RSO apply in LA County or other cities?
Only inside the City of Los Angeles. Unincorporated LA County uses the RSTPO, and other cities have their own laws, if any.
Can I raise rent to market when a tenant leaves?
When a tenant moves out voluntarily, is evicted for nonpayment or an uncured lease violation, or signs a filed buyout agreement, LAHD says the rent can be set at any amount for the next tenant. Other kinds of vacancy follow different rules, so confirm the reason with LAHD before you reset.
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