How Long Does It Take to Get an ADU Permit?

mseirafi
Apr 26
2 min read

When planning an Accessory Dwelling Unit (ADU), a common question is: How long will it take to get the ADU permit approved?

The truth is, waiting for permits can feel like a major hurdle — but understanding the ADU permit timeline helps you plan ahead, avoid surprises, and get your project moving faster.

Typical ADU Permit Timeline

On average, securing an ADU permit takes between 2 to 6 months, depending on:

Project type (garage conversion, detached ADU, JADU)
City or county workload
Completeness of your ADU application
Use of a preapproved ADU plan versus custom plans

Cities offering permit ready ADU plans can often cut the timeline significantly.

Main Factors Affecting Permit Time

1. Completeness of Documents

Submitting a full package — including your ADU blue print, site plans, energy compliance reports, and structural drawings — is critical. Missing information triggers delays.

2. Jurisdiction Efficiency

Cities like Los Angeles, San Diego, and San Jose have streamlined ADU permit processes. Some smaller cities may still have slower plan reviews.

3. Corrections and Revisions

Each correction round (where the city asks for changes) adds 2–4 weeks to the timeline. Using a clean, detailed preapproved ADU plan often minimizes corrections.

4. Project Complexity

Garage conversions: Faster (around 2–4 months)
New detached ADUs: Slower (up to 6 months)

Larger projects with complicated designs may trigger extra structural reviews.

How to Speed Up Your ADU Permit Process

Choose a permit ready ADU plan whenever possible
Submit a complete and accurate ADU blue print package
Work with experienced designers who specialize in ADU permits
Communicate clearly with city planning staff
Respond quickly to any plan check corrections

Early preparation ensures faster approvals and smoother construction starts.

Real-World Example

A homeowner in Santa Clara County submitted a complete ADU permit application using a city’s preapproved ADU plan.Result?Approval in just 7 weeks, shaving months off the standard waiting time.

Common Mistakes That Delay Permits

Missing utility connection plans
Incomplete Title 24 energy compliance documentation
Poorly detailed ADU blue prints
Lack of owner-occupancy affidavit (for JADUs)

Final Thoughts

Securing an ADU permit doesn't have to be a slow or confusing process. At ADUnest, the focus is on helping homeowners prepare complete ADU blueprints, select the best preapproved ADU plans, and submit fast-tracked permit ready ADU plans — reducing approval times and construction delays. If you have any questions about the ADU permit process, required drawings, or how to move forward faster, feel free to leave a comment below.The ADUnest team will respond promptly to assist you.