Ventura County ADU Guide

Unincorporated Ventura County

County standardized detached plans may support Express production for qualifying properties; site and agency requirements remain separate.

Reviewed August 2026Official jurisdiction resource ↗
01 / Plan path

Choose the right production starting point.

County standardized detached plans may support Express production for qualifying properties; site and agency requirements remain separate.

Express PlanStarting at $4,500

For a qualifying jurisdiction preapproved plan adapted into the property-specific architectural production set.

Custom PlanStarting at $6,500

For an original floor plan and architectural production set developed around the property and homeowner.

02 / Size + fee checkpoints

Size affects more than floor area.

Verify local zoning, water, septic, fire, grading, and applicable state-law size protections.

Environmental Health, Fire, Public Works, watershed, grading, and school requirements can create separate thresholds and fees.
500 SFConfirm school-fee assessment rules750 SFState impact-fee protection checkpoint1,000 SFTwo-bedroom state minimum allowance1,200 SFCommon local upper-range checkpoint
03 / Site conditions

Property conditions can change the path.

  • Zoning and Area Plan
  • Fire access, flow, and defensible space
  • Onsite wastewater and water supply
  • Slope, grading, geology, and drainage
  • Coastal Zone when applicable
04 / Consultant screen

Likely disciplines to evaluate.

  • Structural engineering
  • Title 24 energy documentation
  • Survey
  • Civil and geotechnical engineering
  • Septic and fire consultation when applicable

Consultants are retained only when required by the property, design, or reviewing agency. Their proposals and coordination are separate from the architectural production fee unless stated otherwise in the agreement.

05 / Property-specific next step

Turn the guide into a preliminary project report.

Enter the address to screen jurisdiction, mapped constraints, likely agencies, drawing requirements, consultants, and the preliminary fee path.

Check the property →Email Bennett Design Studio →
Important: This guide is general planning information, not a zoning determination, permit approval, fee quote, or guarantee of feasibility. Current parcel records, adopted codes, agency interpretations, utility requirements, site investigation, and written agency confirmation control.