Your New LA ADU Skips Rent Control. For 15 Years.
Chris Koss, AIA|Published July 5, 2026
In Los Angeles, one document decides whether your ADU is rent controlled: the certificate of occupancy. A pre-1978 unit falls under the RSO; a new ADU skips the state rent cap for 15 years, then rolls in.
A backyard accessory dwelling unit in Los Angeles. Photo: David Wagner, via LAist.
Your ADU's rent rules are not in the lease; they are in the certificate of occupancy, a document most owners file and forget. In Los Angeles, that certificate is the whole test: the Rent Stabilization Ordinance reaches only units with a certificate dated on or before October 1, 1978, and state law exempts any home whose certificate is under 15 years old, so a new ADU starts life outside both.
The short version:
- Los Angeles rent control, the RSO, covers only rental units with a certificate of occupancy issued on or before October 1, 1978. A new ADU built in 2026 is not one of them, and never will be.
- California's AB 1482 caps annual rent increases at 5 percent plus inflation, or 10 percent, whichever is lower. It exempts any home with a certificate of occupancy from the previous 15 years, on a rolling basis, so the exemption expires as your ADU ages.
- Exempt from the rent cap is not the same as exempt from eviction rules. LA's citywide Just Cause Ordinance can still reach a unit that both the RSO and AB 1482 pass over.
If you are a tenant touring an ADU, or an owner about to set a rent, this is the paperwork that decides which rules bind you. It is worth ten minutes to read it before you sign.
The certificate is the whole test
Los Angeles runs two rent regimes at once, and a unit can sit in one, both, or neither. The local one is the Rent Stabilization Ordinance. The LA Housing Department is blunt about who it covers: rental units in properties that received a certificate of occupancy on or before October 1, 1978. Roughly 624,000 units across the city qualify. A detached ADU finished this year carries a 2026 certificate, so it will never be an RSO unit. That part is permanent, not a countdown.
The state regime is AB 1482, the Tenant Protection Act, and it works on a clock instead of a cutoff date. Its rent cap and its just-cause eviction rules both wave off new construction for the first 15 years after the certificate issues. The exemption is written into the rent-cap statute in one plain sentence.
"Housing that has been issued a certificate of occupancy within the previous 15 years, unless the housing is a mobilehome." California Civil Code section 1947.12(d)(4)
Read the words "within the previous 15 years" carefully, because they move. The exemption is measured against today, not against the year the law passed. An ADU with a 2026 certificate is exempt now and stays exempt until 2041, at which point AB 1482's cap quietly switches on. Nobody sends a letter. The clock just runs out.
Who wins, who loses, and who has to check
A new detached ADU is the clean case: no RSO, no rent cap for 15 years. The owner sets the rent at market and raises it freely for a decade and a half, which is the whole financial logic behind treating an ADU as an income unit rather than a bedroom. As we covered when we walked through what tenant law actually says about renting a California ADU, that freedom is real but narrower than owners assume.
The messy case is a garage conversion that never pulls its own separate certificate of occupancy. If the city treats the converted space as part of an older, pre-1978 building rather than as a distinct new unit, it can inherit that building's RSO coverage instead of standing on its own 2026 date. Two homes on one parcel can end up carrying two different sets of rent rules: the main house under the RSO, the new ADU exempt, or the reverse. The certificate, again, is what sorts them.
Then there is the trap in the word "exempt." A new ADU skips the rent caps, but LA's Just Cause Ordinance still requires a stated, legal reason to evict from most rentals the RSO does not cover, and owner-occupancy rules can still attach to a junior ADU that shares a kitchen or bath with the main house. If you are a tenant, "not rent controlled" does not mean "no protections," and if you are an owner, it does not mean "no obligations." We unpacked one slice of that overlap in our look at what AB 1154 changed for JADU owner occupancy.
The cross-street check. In San Francisco the same new ADU could be the opposite of exempt. SF's Waiver Program hands owners relief from density and rear-yard rules, but the price is a Costa-Hawkins agreement that puts the new unit under city rent control from day one, while a No-Waiver, state-standard ADU stays out of it. There the program you chose decides the rent rules, not the certificate date. In New York City, a legalized basement unit running on an Authorization for Temporary Residence can land in rent stabilization depending on the building, a third logic again. Same appliance, three cities, three different switches:
| Metro | What triggers rent regulation on a new accessory unit |
|---|---|
| Los Angeles | The certificate of occupancy date. Pre October 1, 1978 means RSO; under 15 years old means AB 1482 exempt. |
| San Francisco | The program. A Waiver-track unit is rent controlled by agreement; a No-Waiver unit is not. |
| New York City | The building and the pathway. A legalized basement unit may enter rent stabilization case by case. |
Our read: the 15-year exemption is a clock, not a carve-out, and treating it like a permanent gift is the mistake we expect to see litigated a decade from now. If you are underwriting an ADU on the rent it commands today, model the year it turns 15 too, because that is when AB 1482's cap arrives on a unit whose rent you set with no cap in mind. It is a good problem to have. It is still a problem.
What to watch
AB 1482 is currently set to sunset on January 1, 2030, unless the Legislature extends it, which would reset the terms of that 15-year clock for everyone. LA's RSO cutoff has held at October 1, 1978 for decades and is not moving. The live variable is the Just Cause Ordinance and how aggressively the city applies eviction protections to the newest slice of housing, the ADUs that have arrived by the tens of thousands since 2017. Watch that space before you assume a new unit is a rules-free unit.
If you want to see how a specific unit's status and terms are laid out before you tour or list it, A-du's rental map shows accessory units with their details in one place across LA, SF, and New York.
The next real test is not a statute but a calendar: the first wave of post-2019 ADUs will start crossing their 15-year mark late this decade, and how owners handle that quiet switch will tell us whether the exemption was a bridge or a cliff.