City ADU Permit Guides
Every city has unique rules. Select your location below for a step-by-step guide to permitting, costs, and mandatory requirements.
Los Angeles
Detailed guides for LADBS requirements.
Seattle
Navigate SDCI rules and ADUniverse gallery.
General Permitting Overview
Required Plan Sets
Most cities require a Site Plan (showing property lines and setbacks), Floor Plans, Elevations (what it looks like from the outside), and Structural Engineering calculations. In 2026, many cities also mandate Energy Compliance forms (Title 24 in CA).
The "Plan Check" Phase
This is the time it takes for city staff to review your plans for safety and zoning compliance. Expect 1-3 rounds of "corrections" where the city asks for specific changes to the drawings.
Impact Fees
Units under 750 square feet are often exempt from major school and park impact fees in many jurisdictions. Always check local thresholds to save $5,000 - $15,000.
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