ADUs & additions in Ventura County.
Design-build for ADUs, garage conversions, and additions in Thousand Oaks, Simi Valley, Camarillo, Moorpark, Oak Park, and unincorporated Ventura County.
Ventura County ADU and addition work spans incorporated cities like Thousand Oaks, Simi Valley, Camarillo, and Moorpark, plus unincorporated county land reviewed by Ventura County RMA. Each city has its own submittal process; we confirm the correct department during feasibility.
Ventura County parcels often have wildfire, hillside, or agricultural-zoning considerations that affect design. Planning for those constraints early is far more cost-effective than discovering them mid plan-check.
Representative Ventura County cities we've worked in
Cities named are examples of our regional coverage, not project addresses. We also work in neighboring communities on request.
Ventura County city guides
Detailed pages covering the reviewing department, local site conditions, and the ADU types that work best in each area:
Ventura County homeowner guides
In-depth guides written for Ventura County homeowners — costs, permits, and local conditions:
Relevant HomeAdd services in Ventura County
Ventura County planning & permits — incorporated cities vs. unincorporated county
For parcels inside Thousand Oaks, Simi Valley, Camarillo, Moorpark, and other incorporated cities, ADU and addition permits go through that city's building and planning department. Each city has its own rules on top of California state ADU minimums.
For unincorporated Ventura County parcels, Ventura County Resource Management Agency (RMA) is the reviewing authority. Their ADU page is the correct starting point.
- Ventura County RMA — Accessory Dwelling Units Permit and planning starting point for unincorporated Ventura County. Incorporated cities use their own departments.
- California HCD ADU Handbook State-level ADU baseline rules for every California jurisdiction.
Common site considerations in Ventura County
- Very High Fire Hazard Severity Zones and defensible space.
- Hillside grading and drainage in Simi Valley and Thousand Oaks foothills.
- Agricultural or open-space overlays affecting siting and utility runs.
- Water and sewer capacity, or septic evaluation on unincorporated parcels.
- Setback rules and second-unit siting on larger semi-rural lots.
- Utility panel upgrades on older homes.
Frequently asked questions
Do you build in Simi Valley, Thousand Oaks, and Camarillo?+
Yes. Those incorporated cities have their own planning and building departments — Simi Valley, Thousand Oaks, and Camarillo each run their own review process. We match design and permit strategy to the specific city.
Does Ventura County RMA handle my ADU?+
Ventura County Resource Management Agency (RMA) handles ADUs and additions in unincorporated Ventura County. If your parcel is inside an incorporated city, that city's department reviews the project.
Are there special considerations for Ventura County wildfire zones?+
Yes. Ventura County has significant Very High Fire Hazard Severity Zones. Fire access, materials, defensible space, and, in some cases, sprinklers factor into design and permitting.
How does agricultural or open-space zoning affect ADUs?+
Parcels zoned agricultural or open-space can still allow ADUs under specific conditions, but review is more involved. We confirm zoning and applicable overlays during feasibility.