The California ADU permit process typically takes 14–21 weeks (about 3.5–5 months) from initial application to permit in hand. However, timelines can range from 4 weeks to over a year, depending on your city and how complete your plans are at first submission. Under state law, cities must complete plan review within 60 days once they deem your application complete. Understanding each stage of the California ADU permit process helps you plan realistically and avoid delays. This timeline applies whether you’re permitting an ADU in Pasadena or elsewhere in the San Gabriel Valley.
Step 1: Feasibility Review
Before drawing anything, we check property lines, utility easements, setback requirements, zoning classification, and electrical panel capacity. These details determine what you’re allowed to build and where it can go on your lot.
Step 2: Design and Plan Preparation
This is the step that matters most for your timeline. A complete, coordinated, code-compliant first submission moves you through city review fastest. Incomplete plans remain the most common cause of permit delays.
Step 3: Application Submission
Most San Gabriel Valley cities now accept ADU applications through an online permitting portal. We handle the submission and act as your point of contact with the building department throughout review.
Step 4: Completeness Check
As of January 1, 2026, state law (SB 543) gives the city 15 business days to determine whether your application is complete. If the city doesn’t respond in that window, your application is automatically deemed complete and the 60-day plan check clock starts.
Step 5: Plan Check and Review
This is usually the longest phase. Building, planning, zoning, fire safety, and sometimes public works departments review your plans, often simultaneously but each on their own timeline.
Step 6: Corrections and Resubmission
Almost no project passes review on the first submission. Expect one or two rounds of corrections, where reviewers flag items and we revise and resubmit. Once you resolve corrections, the city approves your plans and issues your permit.
The 60-Day Rule
By law, once your application is deemed complete, the city has 60 days to act. If they don’t, your ADU application may be deemed approved. In practice, most projects move through review within that window when the initial submission is thorough — which is exactly why a strong first submission matters so much.
Let Us Handle Your California ADU Permit Process
Potato Construction manages the entire ADU permit process for San Gabriel Valley homeowners, from feasibility review through final permit issuance. Contact us or call (626) 777-6666 for a free consultation, or learn more about our ADU services.
Frequently Asked Questions
Most projects take 14 to 21 weeks (about 3.5 to 5 months) from application to permit in hand, though it can range from 4 weeks to over a year depending on the city and how complete your plans are.
SB 543, effective January 1, 2026, requires cities to determine if your ADU application is complete within 15 business days. If they don’t respond, the application is automatically deemed complete and the 60-day plan check clock starts.
Incomplete or uncoordinated plans on the first submission. A complete, code-compliant plan set the first time is the single biggest factor in avoiding multiple rounds of corrections and delays.
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