State overview
ADU permits in California
California sets the outer limits for accessory dwelling units in state law, and each city or county runs its own application process inside them. Start with the state rules, then read the notes for your city.
City notes
Cities and counties
Local checklists, extra documents and how each office handles review.
- San Diego
- Los Angeles County
- Los Angeles
- Long Beach
- Menlo Park
- Sacramento
- Pleasanton
- Oakland
- Moreno Valley
- San José
- San Diego CountySan DiegoSan Diego goes further than state law in several places, most visibly on setbacks.Reviewed November 10, 2026
- Los Angeles CountyLos Angeles CountyThe County hadn't amended its ADU ordinance when the 2026 state changes arrived, so its planning director told staff in a memo how to apply them.Reviewed November 10, 2026
- Los Angeles CountyLos AngelesLos Angeles still runs on a 2019 ADU ordinance, read through a joint Planning and Building memo from the end of 2024.Reviewed November 10, 2026
- Los Angeles CountyLong BeachLong Beach publishes a fill-in application for simple garage conversions, and a separate route through pre-approved plans.Reviewed November 10, 2026
- San Mateo CountyMenlo ParkMenlo Park's current ADU checklist is dated March 2026 and is built around the state's two-step review.Reviewed November 10, 2026
- Sacramento CountySacramentoSacramento runs ADUs through Planning before Building, allows two per lot, and prints its fee and sprinkler thresholds on a two-page handout.Reviewed November 10, 2026
- Alameda CountyPleasantonPleasanton's preapproval program is aimed at the people who draw ADUs, not the people who order them.Reviewed November 10, 2026
- Alameda CountyOaklandOakland asks applicants to certify their project against a building criteria checklist.Reviewed November 10, 2026
- Riverside CountyMoreno ValleyIn Moreno Valley the drawings are only half the job.Reviewed November 10, 2026
- Santa Clara CountySan JoséSan José lays its ADU process out in six steps and tells you, quite openly, which missing document holds up the most projects.Reviewed November 10, 2026
Guides
When an application stalls
How the process works, and what to do at the points where it tends to stop.
- GuideHow long an ADU permit takes in CaliforniaState law doesn't promise a fast permit, but it does put the city on a clock at three points. Knowing which clock is running tells you whether you're waiting on the city or the city is waiting on you.Reviewed November 10, 2026
- GuideYour ADU application was marked incomplete. What now?An incomplete notice feels like a rejection. It isn't one. It is a list, and since 2026 the city is held to that list.Reviewed November 10, 2026
State law
The rules every city must follow
The Government Code sections applicants run into most, explained simply.
- State lawADU impact fees and the 750 square foot lineA few square feet can decide whether an ADU owes impact fees at all. The line is drawn at 750, and it is measured in a specific way.Reviewed November 10, 2026
- State lawLegalizing an unpermitted ADU built before 2020If a unit on your property was built without permits before 2020, state law narrows the reasons a city can refuse to permit it now. The protection is real, and it has an edge you need to know about.Reviewed November 10, 2026
- State lawSB 543: what changed for ADU permits in 2026SB 543 didn't change what you can build so much as how your application has to be handled. It also renumbered parts of the code, which is why older guides now point to sections that have moved.Reviewed November 10, 2026