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ADU permit denied: common causes and next steps

By the HyreADU research desk. Last checked .

The short answer

An ADU permit denied or held incomplete usually comes down to a fixable gap: missing documents, a design that breaks an objective standard, or a site issue such as setbacks, fire access or utilities.

In California, the city must tell you in writing what is missing within 15 business days and give a full set of comments with a denial. Fix each item and resubmit.

Why it happens

  • The application was incomplete: missing energy forms, structural calculations or a site plan.
  • The design breaks an objective standard: height, setbacks, size or a design rule.
  • A site issue: fire access, utility capacity, a flood or coastal zone, an easement.
  • A building code problem: escape openings, fire separation, structural details.

What California requires the city to do

California sets clocks. The city must decide a complete ADU application within 60 days, and if it misses that, the application is deemed approved (Gov. Code § 66317).

Since January 1, 2026, the city must also say in writing within 15 business days whether an application is complete and list what is missing.

If it denies the permit, it must give a full set of comments with what is deficient and how to fix it.

An appeal of incompleteness or denial gets a final written determination within 60 business days.

What to do this week

  1. Get the denial or incompleteness letter and every comment in writing.
  2. Ask for the code section behind each comment.
  3. Sort the comments: documents to add, design changes, and site issues.
  4. Meet the plan checker or planner if the comments are unclear.
  5. Revise and resubmit as one complete package; the ADU permit checklist helps.

Who fixes it

Your designer handles drawing changes, your engineer structural or soils comments, and your Title 24 consultant energy comments.

If a comment seems to apply a rule state law does not allow, you can ask the city to explain the basis in writing.

California’s HCD reviews local ADU ordinances for compliance; we give no legal advice on disputes. See ADU permit expediter.

What it costs

The costs are redesign time, resubmittal or plan check fees under your city’s schedule, and delay. We publish no amounts. A complete first submission is the cheapest fix; see ADU plan check delays.

A mistake to avoid

The mistake to avoid is resubmitting piece by piece. Each partial answer can start another round of review. Collect every comment, answer all of them, and send one complete package with a response letter that lists each comment and where it was fixed.

What to do next: check your lot with the ADU feasibility checker, read the questions to ask an ADU builder, then tell us about your project. Matching is not live yet, so we reply with information, not a quote.

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Questions

Can a city deny an ADU in California?

Yes, if it does not meet objective standards or building codes. It must explain why in writing.

What does “deemed approved” mean?

If the city does not act on a complete application within 60 days, the law treats it as approved. Ask the city how it applies this.

Can neighbors cause a denial?

Not by objecting alone; ADU review in California is ministerial. See neighbor objection.

Should I hire a lawyer?

For a dispute over whether the city applied the law correctly, a land use lawyer can advise. We cannot.

Sources

HyreADU is a publisher. It does not design, permit or build ADUs, has no partner builders, and gives no legal, tax, lending or engineering advice.

Rules vary by state and city; California rules are labeled as such. Spotted an error? Tell us through our corrections page. Licensed professionals can also contribute as named sources.