Permitting 101: A Beginner’s Guide to ADU Permits

More than 60% of ADU projects face delays because of permit confusion. Here’s how to avoid that. Before you break ground or hire a contractor, there’s one crucial step you can’t skip: permits. While the permitting process can feel overwhelming at first, this guide will walk you through the essentials—so you can get started with clarity and confidence.

What is a Permit — and Why Do You Need One?

A permit is official approval from your local government that allows you to build legally. For ADUs, that includes everything from zoning to construction and safety standards. Getting a permit ensures your project:

• Meets building codes
• Follows zoning rules
• Is safe for occupancy

Skipping permits can lead to fines, stop-work orders, or even having to tear down your ADU. Not worth the risk.

‍

Step 1: Check Your Local ADU Rules

Every city and county has its own ADU regulations. Before drawing up plans, check:

• Is your property zoned for an ADU?
• How large can your ADU be?
• Are there setback or height limits?
• Do you need parking for the ADU?

Many cities have ADU checklists or “pre-approved” plans. Start with your city’s planning department website or give them a call.

Step 2: Prepare and Submit Your Application

You’ll likely need to submit:

• Site plans
• Floor plans
• Elevations
• Structural calculations
• Energy compliance forms (Title 24 in California, for example)

Some cities allow digital submissions, while others require paper plans. Fees also vary—some areas even waive them for ADUs.

Step 3: Plan Review and Revisions

After you submit, your local agency will review your plans. They may request corrections or clarifications. Be ready to:

• Revise drawings
• Resubmit documents
• Wait a few weeks (sometimes longer)

Hiring an experienced drafter or architect can save time here—they know what reviewers are looking for.

Step 4: Permit Approval and Inspections

Once approved, you’ll receive your building permit. This must be posted on-site before construction begins. During the build, inspectors will visit at key points—foundation, framing, electrical, and more—to ensure everything is up to code.

Final Inspection = Green Light

After the final inspection, your ADU gets a certificate of occupancy. That means it’s safe, legal, and ready to use—whether you're renting it out or moving in a family member.

‍