ADU

Five months into a stalled ADU application, most owners assume waiting is the only option. California law says otherwise: miss the deadline on a complete application, and the permit is approved by operation of law. Here's every clock the city is running against.

Your kids moved out and the back of the house is empty. California has a category for exactly that: a small independent unit carved out of the walls you already own, with no parking required and a kitchen the city can't make fancier than the law says.

You built the backyard unit, and now you'd rather sell it than rent it. California opened a door to that in 2024 — but only if your city walked through it first, and only after your mortgage lender signs off in writing.

The planner tells you the ADU needs a parking space, and the garage you were going to convert has to be replaced somewhere else on the lot. Both statements may be wrong. California law caps what a city can ask for — and lists six situations where it can ask for nothing at all.

Explore the regulations and opportunities for building ADUs and JADUs in Los Angeles, CA, to maximize property value and space.

You sketched a 1,000-square-foot backyard cottage and the city said their cap is smaller. Who wins? California's ADU law sets hard ceilings on what cities may restrict — and a guaranteed unit every city must approve.

Discover how Emily leveraged GoCodebook AI to explore ADU and JADU possibilities for her Cupertino property.

Explore the rules and opportunities for building ADUs and JADUs on Los Angeles' hillside properties. Maximize your property's potential!

When an Accessory Dwelling Unit (ADU) shares a wall or ceiling with a garage, that separation must provide adequate fire protection between the habitable space and the area used for vehicle storage. The rules come from the 2025 California Residential Code (CRC) and the 2025 California Building Code (CBC), which apply to all R-3 Occupancy, Type VB residential construction.

ADUs are allowed on lots zoned for single-family or multifamily use with an existing or proposed dwelling. Only one ADU is allowed per lot under “state” standards, and the lot must not contain another ADU or a Junior ADU (JADU).

For Accessory Dwelling Units (ADUs) in San Francisco, the Planning Code does not impose any minimum size for an individual room within the ADU. The Code is clear that the City cannot require any minimum or maximum overall size for an ADU that would prevent the construction of an ADU up to 800 square feet in gross floor area, provided all other requirements are met. There is no clause specifying a minimum square footage for rooms within ADUs, only maximum square footages for total ADU size applicable in some circumstances.