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ADU Permit Fee Estimator
Estimate ADU permit fees and approval timelines for 100 California cities. Sourced from official planning departments — not ballpark guesses.
ADUs under 750 sq ft qualify for a state impact fee waiver. The calculator flags this automatically.
What ADU Permit Fees Cover
Permit fees are not a single number — they are a collection of charges from multiple agencies. Here is what you are typically paying for.
City review of your architectural and engineering drawings. Usually paid upfront before permit issuance.
Covers city inspections during construction. Paid when permit is issued.
Separate sub-permits for each trade. Some cities bundle these; others charge individually.
Waived for ADUs under 750 sq ft per state law. Larger ADUs may owe fees to local school districts.
If you want a separate electric meter or new water connection. Not required in most cities.
ADU Permit Fee Questions Answered
How much are ADU permit fees in California?
ADU permit fees in California typically range from $5,000 to $25,000, depending on the city, project complexity, and ADU size. High-cost cities like San Francisco and Los Angeles trend toward the higher end. Smaller cities often have lower permit costs.
Are impact fees waived for ADUs?
Yes — California state law waives impact fees for ADUs under 750 square feet. For ADUs 750 sq ft and above, impact fees must be proportionally reduced compared to a new primary dwelling. This waiver can save $5,000–$30,000 in cities with high impact fees.
How long does an ADU permit take in California?
State law requires cities to process ministerial ADU permit applications within 60 days. Some cities have express programs that process approved plans in 30 days or less. Los Angeles has an Express ADU program targeting 30-day approvals.
What documents do I need for an ADU permit?
Typical required documents include: a site plan to scale, floor plans showing new and existing construction, elevation drawings, structural calculations, Title 24 energy compliance documentation, and sometimes a soils report. Your city's planning department can provide a complete checklist.
Can I get an ADU permit online?
Many California cities now offer online permit portals. Sacramento, Los Angeles, San Diego, and San Jose all have digital submission options. Some cities also offer pre-approved standard ADU plans that can dramatically speed up the process.
What is the difference between a plan check fee and a building permit fee?
A plan check fee covers the city's review of your submitted drawings. A building permit fee is paid when the permit is issued and covers inspections during construction. You typically pay both, plus separate fees for electrical, mechanical, and plumbing permits.
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