Start with your city
Every Ventura County city, and the county for unincorporated areas, takes its own ADU applications. Most start with a planning review and end with a building permit. The table links each one's official ADU page and summarizes what that page offers, with the permits each has reported and how long they took.
| City or area (official ADU page) | ADU permits reported in 2025 | Median days, application to permit |
|---|---|---|
| Camarillo Starts with a Planning zone clearance, submitted through the city's OpenGov portal. | 35 | 80 |
| Fillmore An ADU administrative clearance from Community Development, then a building permit. | 7 | — |
| Moorpark Building & Safety; the page offers standard ADU plans (700, 900 and 1,188 square feet). | 26 | 80 |
| Ojai The page posts the city's ADU packets (including a compliance packet). | 32 | 58 |
| Oxnard Planning pre-review by email, then submittal to Building & Engineering; no separate zoning clearance. The page has submittal checklists and links information on pre-approved ADUs. | 237 | 428* |
| Port Hueneme Planning & Zoning; an ADU submittal checklist and the city's OpenGov portal. | 13 | 36 |
| Santa Paula Community & Economic Development; an ADU guidebook. Its standard plans are posted as drafts. | 0 | — |
| Simi Valley The Planning Division's page has an ADU guide; the city notes its ADU ordinance is being updated. | 192 | 211 |
| Thousand Oaks Planning review, then Building plan check and permit through the TO24 portal; an ADU plans gallery that includes pre-approved plans. | 117 | 146 |
| Ventura Planning and Building & Safety; free standardized detached plans (1, 2 and 3 bedrooms) pre-approved by Building & Safety. | 163 | — |
| Unincorporated Ventura County The county's Resource Management Agency: a building permit only, for ADUs meeting state standards (else a Planning zoning clearance); free standardized detached plans pre-approved by Building & Safety. | 101 | 221 |
* Includes planning review: this city reports its planning application date.
Page summaries reflect each official page as checked on September 28, 2026; cities update their pages, so follow the links for current requirements.
Before you apply
- Check whether your city offers pre-approved or standard plans; they can shorten review.
- Ask for the city's submittal checklist and fee schedule, and whether planning review comes first.
- State law requires a decision on a complete application within 60 days.
See also: California ADU rules, ADU permit times in Ventura County, choosing a licensed builder.
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General information, not legal, zoning or financial advice. Rules change
and depend on your lot; check with your city before you design or build.