Ventura County ADU Guide

Thousand Oaks

City guidance and property conditions determine whether an existing starting plan or a Custom Plan is appropriate.

Reviewed August 2026Official jurisdiction resource ↗
01 / Plan path

Choose the right production starting point.

City guidance and property conditions determine whether an existing starting plan or a Custom Plan is appropriate.

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.

State-law minimum size protections remain relevant; confirm the City’s current maximum and objective development standards.

Projects at or below 750 square feet receive state impact-fee protection, while school, plan-check, utility, and other charges may still apply.
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.

  • Oak and landmark tree protection
  • Fire Hazard Severity Zone
  • Hillside and grading
  • Utilities and drainage
  • Homeowners association requirements outside City permit review
04 / Consultant screen

Likely disciplines to evaluate.

  • Structural engineering
  • Title 24 energy documentation
  • Survey
  • Arborist, civil, geotechnical, or fire consultation when triggered

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.