How Long Does ADU Permitting Take?
In states with streamlined ADU laws, ministerial approval can take as little as four to eight weeks from a complete submittal. In other jurisdictions, three to six months is common. The biggest variable is submittal quality: complete packages move, and most delays come from correction cycles, not review queues.
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What streamlined review looks like
California law sets a 60-day target for ministerial ADU approval once the application is deemed complete, and several other states have adopted similar shot clocks. Ministerial means no discretionary hearings or neighbor-approval processes. These timelines apply to the review itself; they do not include the time you spend preparing plans or responding to corrections.
What slows projects down
Incomplete structural or energy documents, zoning questions that need variances, utility capacity sign-offs, and septic or well reviews are the usual delay sources. Each correction cycle typically adds weeks. Projects that need discretionary approvals, like coastal permits or historic review, run on separate and longer tracks entirely.
How to move faster
Book a pre-submittal meeting to surface issues before you draw, submit a complete coordinated package the first time, and respond to corrections quickly and completely rather than in drips. Hiring designers who have permitted ADUs in your specific city matters: they know that plan checker's correction patterns and design around them.
The bottom line
Permitting time is mostly within your control. A complete, code-compliant first submittal is the fastest lever you have.