Thousand Oaks, CA Accessory Structures: ADU Rules (2026)
ADU rules in Thousand Oaks, CA, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.
Key Facts
- Review type
- Ministerial: no discretionary review or hearing
- Decision deadline
- 60 days from a complete application
- Permits needed
- Separate ADU permit AND building permit
- Denial requirement
- City must list specific defects and how to fix them
Summary
Thousand Oaks must review ADU and Junior ADU (JADU) applications ministerially, no discretionary review, no public hearing, as long as the project meets the city's objective standards. The city has 60 days to approve or deny a complete application when there's already a home on the lot, and a denial must come with a full list of what needs fixing.
(a) Except as provided in Sec. 9-4.4513, no ADU or JADU may be created without an ADU permit and a building permit. ... An application for development of a ADU or JADU created pursuant to this Article will be reviewed ministerially, without discretionary review or a hearing, and approved if it meets all the requirements set forth in Sec. 9-4.4504 through Sec. 9-4.4508 (inclusive).
(b) ADU and/or JADU applications must be ministerially approved or denied within 60 days from the date a complete application is submitted if there is an existing single- or multi-family dwelling on the lot, unless the applicant requests a delay, in which case the 60-day time period is tolled for the period of the delay.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 S-78: 2026 S-78 Supplement contains: Current city legislation passed through March 31, 2026).
Full Breakdown
Both an ADU permit and a separate building permit are required, but review is ministerial (no hearing) whenever the project meets the objective size, setback, and design standards in §§9-4.4504 through 9-4.4508. If the application is submitted alongside a permit for a brand-new primary dwelling on the same lot, the city may delay the ADU decision until it rules on the primary home, but still without discretionary review of the ADU itself. Any denial must include a complete list of deficient items and how to fix them, and modifications to an already-approved ADU need a new permit processed under this same section.
Violations & Fines
The code doesn't set a penalty here since this section defines the city's approval duty rather than a resident obligation; a denied application must be accompanied by a full list of defects the applicant can correct and resubmit.
Frequently Asked Questions
Can Thousand Oaks deny my ADU application at a public hearing?
How long does the city have to decide on my ADU permit?
Sources & Official References
Other rules in Thousand Oaks
How Thousand Oaks compares: Easiest Cities to Build an ADU·California rules heatmap·Compare Thousand Oaks to another location·View the California accessory structures overview
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ADU Rules in Nearby Cities
How other cities in Ventura County handle adu rules.