How Long Does ADU Approval Take?
One of the biggest surprises for homeowners starting an ADU project is how long the permit process takes.
While California law requires cities to review ADU applications quickly, the real timeline depends on how complete your plans are when you submit.
Here’s what you can expect and how to keep things moving smoothly.
State Law vs. City Reality
By state law, cities must approve or deny ADU permits within 60 days of a complete submittal.
But “complete” means your architectural, structural, energy, and site plans are fully coordinated.
If the submittal is missing details or forms, the 60-day clock pauses.
In practice, most projects go through two to four months of city review.
The Plan-Check Process
Most cities (like Fullerton, Pasadena, or Irvine) run the following sequence:
Planning Division – checks setbacks, height, and zoning
Building & Safety – reviews structural, energy, and code compliance
Public Works – confirms utilities and grading (if needed)
Each department may issue comments that your architect must respond to.
That’s why having a complete, well-organized plan set is key to keeping the timeline predictable.
How an Architect Speeds It Up
Architects who specialize in ADUs know how to package drawings the way each city prefers.
At Backyard Project, we include all required forms, Title-24 energy reports, and clear plan labeling.
This minimizes correction cycles and helps approvals move faster — often within 6–10 weeks.
Common Delays to Avoid
Delays usually come from:
Incomplete drawings or missing consultant reports
Conflicts between architectural and structural plans
Utility coordination (especially sewer connections)
Late city responses during peak season
Early coordination and clear communication prevent 90% of these slowdowns.
Final Thoughts
Getting an ADU permit doesn’t have to be stressful.
With the right preparation, most projects in California can move from design to approval in a few months.
Start early, plan clearly, and submit once not three times.