In San José, know which rent regime a building falls under before you make an offer. Three-plus units built and occupied before September 7, 1979 means the city's 5% cap. Most other rentals 15 years and older fall under the state cap. On single-family lots, the city allows ADUs on a property with a duplex, which opens more combinations than many owners expect.
Adding an ADU
In San Jose
The city says its ADU ordinance allows ADUs on a property that contains a duplex, so a single-family lot could be redeveloped with a duplex and up to two ADUs.[1]
In December 2025, HCD noted that the most recent San José ADU ordinance on file with the state was from 2021 and may be outdated under current state law.[2]
State law, everywhere in California
A city has 60 days to approve or deny a complete ADU or junior ADU (JADU) permit application.[3]
Lot coverage, floor area ratio, and front setback rules can't be used to block an ADU of at least 800 square feet with four-foot side and rear setbacks.[3]
A city can't set a height limit below 16 feet for a detached ADU, or below 18 feet within a half mile of a major transit stop or high-quality transit corridor. Attached ADUs can go to 25 feet or the main home's zoning height, whichever is lower.[3]
A JADU is up to 500 square feet of interior space inside the main home. Owner occupancy can't be required for an ADU, but it is required for a JADU that shares a bathroom with the main home.[3]
No impact fees on an ADU of 750 square feet or less. Above that, fees have to be proportional to the main home.[3]
On a lot with an existing apartment building, state law allows up to eight detached ADUs (never more than the number of existing units), plus conversions of non-living space.[3]
Lot splits and second homes
In San Jose
The City Council adopted an SB 9 urgency ordinance on December 14, 2021, which limits a split to two units per lot and sets alternate standards for frontage, depth, and access.[1]
After an April 22, 2024 Los Angeles Superior Court ruling invalidated SB 9 in five Southern California charter cities, San José said SB 9 remains in effect in San José.[1]
State law (SB 9)
SB 9 applies to lots zoned single-family. It allows two primary homes on one lot, a split into two lots, or both, with staff-level approval and no public hearing.[4]
Local rules can't stop two homes of at least 800 square feet each, or a split into two lots of at least 1,200 square feet. Side and rear setbacks are capped at four feet.[4]
Parking is capped at one space per unit, and none can be required within a half mile walk of a high-quality transit corridor or major transit stop, or within a block of a car-share vehicle.[4]
To split a lot, you sign an affidavit that you intend to live in one of the units as your main home for at least three years. Any rental has to be for more than 30 days.[4]
SB 9 doesn't apply if the project would demolish or alter rent-restricted housing, rent-controlled housing, or housing a tenant has lived in during the last three years. It also excludes historic properties, lots with an Ellis Act withdrawal in the last 15 years, lots already created by an SB 9 split, and lots next to one the same owner split.[4]
The ceiling is four units total. After a split, the city has to allow two units on each new lot. The city must decide on a complete application within 60 days.[4]
Rent control and AB 1482
In San Jose
The Apartment Rent Ordinance covers apartments with three or more units built and occupied before September 7, 1979.[5]
Covered units are limited to one 5% increase in a 12-month period. Increases after a voluntary vacancy or a lawful eviction are exempt.[5]
Single-family homes, ADUs, duplexes, condos, townhomes, and units first rented after September 7, 1979 are exempt from the ordinance. Many of those still fall under AB 1482.[5],[6]
State law (AB 1482)
Under the Tenant Protection Act (AB 1482), rent can't go up more than 5% plus the change in the cost of living, or 10%, whichever is lower, in a 12-month period.[6]
After a tenant has lived in a unit for 12 months, the landlord needs a listed reason to end the tenancy, either at-fault (like nonpayment) or no-fault (like owner move-in or a substantial remodel).[6]
Exempt: units with a certificate of occupancy issued in the last 15 years (a rolling date), single-family homes not owned by a corporation or REIT, a duplex where the owner lives in the other unit, and units already under a stricter local rent control law.[6]
What is your San Jose home worth, and what could it become?
I spent my career on the investment side, helping operate more than 7,000 units. I'll give you a valuation built from recent sales, and a straight read on what your lot allows: an ADU, a split, or neither.
San Jose questions, answered
Which San José apartments are rent controlled?+
Apartments with three or more units built and occupied before September 7, 1979, under the Apartment Rent Ordinance. They're limited to one 5% increase in a 12-month period.[5]
Are duplexes and condos covered by San José's rent ordinance?+
No. The ordinance exempts single-family homes, ADUs, duplexes, condominiums, and townhomes. Many of them may still fall under the state Tenant Protection Act.[5],[6]
Is SB 9 still in effect in San José?+
Yes, according to the city, despite an April 2024 court ruling that invalidated SB 9 in five Southern California charter cities.[1]
- [1]City of San José, “About Senate Bills 9 & 10”
- [2]HCD, “San José ADU Ordinance Updates, Letter of Technical Assistance, December 10, 2025”
- [3]California Department of Housing and Community Development (HCD), “ADU Handbook (March 2026 update)”
- [4]California Department of Housing and Community Development (HCD), “Housing Law Fact Sheet: Duplexes and Lot Splits (SB 9), April 2026”
- [5]City of San José, “Learn About Rent Stabilization”
- [6]California Attorney General, “Landlord-Tenant Issues: Tenant Protection Act”
Official San Jose pages
This page is general information, not legal or tax advice. Rules change, and cities amend their codes after state reviews. Confirm current requirements with the city and a qualified professional before you buy, build, or change a tenancy. Erica Walters, REALTOR®, CalDRE# 02239622, Compass.