ADU rules by city
State law sets the floor everywhere in California. Your city adds its own details on top. Here is what applies where we build, checked October 2026.
Neighborhoods and cities we serve
Every Los Angeles neighborhood follows the City of LA rules. Cities with their own rules are checked for your address.
Not listed? Send your address and we will check it.
City of Los Angeles neighborhoods
LA County areas
Other cities we serve
Cities in LA County
LADBS, the Standard Plan Program list of pre-checked designs, hillside and fire-zone checks, and rent control on older buildings.
Learn moreAltadena, East LA and other county areas: free county Plans A, B and C, and an expedited lane for 2025 fire rebuilds.
Learn moreFree PAADU plans "Sevila" and "Casita" with same-day permits, plus coastal-zone and soils checks.
Learn moreThe free Prototype A plan, a 16 ft limit in historic districts, and extra plans for Eaton Fire lots.
Learn moreADUs can be sold as condos, a coastal zone, a mandatory seismic program and rent control.
Learn moreADUs can be sold as condos, and the city runs its own ADU Legalization Program.
Learn moreSize and height change by area, and one lot can carry several ADUs.
Learn moreSize goes by bedroom count, 2 ft setbacks on alleys, and city plans in three styles.
Learn moreFour pre-approved plans, a Planning review first, and coastal and hillside lots.
Learn moreCities in Orange County
HOAs on nearly every lot, the Standard Plan Program and IRWD water and sewer.
Learn moreAttached two-car garages made for conversions, Anaheim Hills fire zones and a city utility.
Learn moreCounty pre-approved plans, canyon fire zones and clay soils.
Learn moreInland Empire and Ventura
What state law guarantees
Every city has to allow these, whatever its own rules say.
Up to 1,200 sq ft on a lot with a house, with 4 ft side and rear setbacks.
16 ft for a detached ADU; 18 ft near transit; 25 ft for an attached ADU.
Up to 500 sq ft inside the house, alongside the ADU.
One detached ADU for every existing unit, up to eight, plus conversions of garages and storage (SB 1211).
Your city not listed?
We build across Los Angeles, Orange, San Diego, Riverside, San Bernardino and Ventura counties. State law applies everywhere, and we check your city's own rules, pre-approved plans and fees for your address before anything is drawn.
We look up the zoning, the city's ADU rules and any pre-approved plans.
What fits on your lot, in plain words, free.
When the rules change, you'll know
A short email when ADU law changes in Southern California, plus new projects and plans. A couple of times a month at most. Unsubscribe anytime.
What does your city allow?
Send the address. We check it against state law and your city's rules and tell you what fits.