The ADU Decision · Part 4 of 5
Investor Education · 3 min read
Before You Pull the ADU Permit: The 60-Day Clock, the Parking Rule, and the Lot Limits
California's accessory dwelling unit (ADU) law gives homeowners something rare: a permit the city can't stall. But the protection has conditions, and most delays I see come from owners who didn't know them.
How long does the city have to approve an ADU?
Sixty days from a complete application, and if the city misses that deadline, the application is deemed approved. There's no public hearing, no design review board, and no neighbor appeal. If your plans meet the objective standards, the city must issue the permit.
The word that matters is complete. The clock doesn't start until your application has everything required. Since January 1, 2026, the city has 15 business days to tell you what's missing, or the application is treated as complete. If the city denies your application, it has to give you a written list of every deficiency and how to fix it.
Two things stop the clock. If you ask for a delay, the 60 days pause for as long as the delay lasts. And if you apply for an ADU together with a brand-new main house, the city can hold the ADU until the house is approved.
Can I build an ADU on an empty lot?
No. An ADU is an accessory to an existing or proposed main home. Without a main house, you're building a small single-family home, and the city's ordinary zoning and permit process applies.
How many units can one single-family lot hold?
Three, by right: one ADU converted from existing space (often the garage), one junior accessory dwelling unit (JADU) inside the house, and one new detached ADU. Together with the main house, that's potentially four households on one lot.
Do I lose my parking if I convert the garage?
You lose the spaces, but the city can't make you replace them when the garage becomes an ADU. The trap is converting the same garage into a "rec room" or "family room." That isn't an ADU, so local zoning applies, and many cities will require a replacement carport. If there's any chance the space will ever house a person, permit it as an ADU now and use it however you like in the meantime.
What about the cost of site work?
Part 3 covers it, including why a prefab ADU's quoted price leaves out the foundation, utility trenching, and the sewer line. Get the site-work bid before you submit plans, not after the permit is issued.
I'm a property manager, not an attorney. Confirm your city's current submittal requirements before you apply.