How ADU permits work across Camarillo, Ventura, Thousand Oaks, Oxnard, Moorpark, Simi Valley, and Malibu. Fees, timelines, and process.
The short answer.
Every ADU question comes down to four variables: California state law, local jurisdiction interpretation, your specific site and parcel, and your program goals. This guide walks through how each applies to the topic at hand, with real numbers from 127 plus ADUs David has permitted across Ventura County and Southern California since 2020.
California state law in 2026.
California law gives every single family parcel the right to add at least one ADU. The law has continuously expanded since 2017, with the most recent updates in 2025 reducing setbacks, capping impact fees, and streamlining permit timelines. The current statewide maximums are 1,200 sq ft for detached ADUs, the greater of 1,200 sq ft or 50 percent of the primary dwelling for attached ADUs, and 500 sq ft for junior ADUs. All of those apply in every city in Ventura County and most of Los Angeles County.
How Ventura County cities handle it.
Camarillo, Ventura, Oxnard, Moorpark, Simi Valley, and Thousand Oaks all implement California ADU law consistently but with small jurisdiction specific differences. Camarillo has the fastest permit turnaround in the county at 58 days on average. Thousand Oaks has the most design review intensive process at 82 days average. Malibu requires Coastal Commission review and can run 110 days or more on coastal parcels.
What it means for your project.
Every project is different. A 600 sq ft garage conversion in Camarillo costs and takes dramatically different time than a 1,200 sq ft detached ADU in Malibu. The variables matter. Call David at (805) 444 1230 or submit your project on the homepage intake form for a site specific analysis.
Key takeaways.
California ADU law is homeowner friendly and continues to expand. Ventura County cities generally handle ADUs well. Cost ranges are predictable. Timelines are achievable. The biggest variable is picking a designer and contractor who have done this work before and know the specific jurisdiction where your parcel sits.