What Does an ADU Permit Cost in Ventura County?

Permit and plan check fees vary by jurisdiction and are generally based on the valuation of the work. Beyond those there can be impact fees, school-related fees and utility connection charges. An ADU with 750 square feet of interior livable space or less is generally exempt from certain local agency, special district and water corporation impact fees.

The categories

• Plan check and building permit fees. Set by your jurisdiction, usually driven by the valuation of the work.
• Impact fees. Local agency, special district and water corporation impact fees, subject to the 750 square foot rule.
• School fees. Governed by separate rules from impact fees. Do not assume the 750 square foot threshold covers them.
• Utility connection charges. Water and sewer connection or capacity charges, separate from the building permit.
• Additional approvals. A Coastal Development Permit in Oxnard's Coastal Zone, or septic review on unincorporated parcels.
• Reports and engineering. Soils, drainage, structural or arborist reports where required.

The 750 square foot threshold

An ADU with 750 square feet of interior livable space or less is generally exempt from certain local agency, special district and water corporation impact fees. A JADU of 500 square feet or less is treated similarly. Above 750 square feet, those impact fees are generally charged in proportion to the size of the primary dwelling.

Local examples

Santa Paula states that ADUs of 749 square feet or smaller are not subject to impact fees.

Camarillo requires a solar electric system on new detached ADUs, a construction cost rather than a fee but part of the same budget conversation.

See the full ADU cost guide or ADU permits.

ADU laws and local requirements can change. Information on this page is general and is not a guarantee that a specific project will be approved. Confirm current requirements for the property and jurisdiction before making project or financial decisions.