Thousand Oaks, CA Accessory Structures: ADU Permits (2026)

Title 9 (Planning and Zoning) of the TOMC contains the city's ADU regulations, which are required by state law to conform to Gov. Code §65852.2 and §65852.22. Applications go to the Community Development Department (805-449-2100) and are processed ministerially: no Planning Commission hearing, no CEQA review for individual ADUs (state-law exempt), and no discretionary design approval. Per Gov. Code §65852.2(a)(3), the City must approve or deny a complete application within 60 days, or the permit is deemed approved by operation of law. Permitted by-right are one detached ADU up to 1,200 sq ft, one attached ADU (up to 50% of the primary dwelling or 1,200 sq ft, whichever is less), one conversion ADU within existing space, and one JADU up to 500 sq ft within the walls of the primary dwelling. State law's 800 sq ft / 16-foot / 4-foot setback floor applies regardless of underlying zoning. Building plans must comply with the 2025 California Building, Residential, Plumbing, Mechanical and Electrical Codes. Much of Thousand Oaks sits in a Cal Fire State Responsibility Area (SRA) High or Very-High Fire Hazard Severity Zone, so plans typically must also satisfy CBC Chapter 7A wildland-urban interface (WUI) construction standards (ignition-resistant exterior, ember-resistant vents, Class A roof).