Accessory Dwelling Units (ADUs) are an innovative and effective option for adding much needed housing in California. ADUs have been known by many names: granny flats, in-law units, backyard cottages, secondary units and more.
Several State laws enacted in 2017 and 2019 require local governments to allow properties with one existing single family dwelling unit to add an ADU and/or a Junior (Jr) ADU by submission of building permits and payment of related fees. In most cases, additional off-street parking is not required for the ADU and/or Jr ADU, although it is highly recommended and encouraged.
ADU Permitting Process
To qualify for a plan check for your ADU, you must have your plans prepared and have completed to the following four steps:
STEP #1 – Meet with the Planning Department to ensure the project meets preliminary planning requirements. For more information, see the FAQ below.
STEP #2 – Submit a complete application package. Provide a complete building plan submittal package including the following:
- Building Permit Application
- Plan Submittal Checklist
- Junior ADU Checklist (if proposing a Jr. ADU)
- Expanded ADU Checklist
- 3-sets of full-size plans + 2-sets of calculations (structural, if applicable and energy) and other supporting documents.
STEP #3 – The plan submittal package must be turned in to Building & Engineering, 214 South C Street Oxnard CA 93030 during our open counter hours. Staff will screen the plans for completeness and calculate the associated plan check fee, to be paid prior to beginning the plan check. Plan check fees are based on project valuation.
Frequently Asked Questions
An ADU is a small residential unit on a permanent foundation that is intended to provide relatively affordable housing for family members, the elderly, students, in-home health care providers, the disabled, and others within existing neighborhoods and on existing legal lots with a “Primary Unit” single family dwelling.
ADUs may be a new detached structure in the rear yard (with or without a garage), an attachment to the existing Primary Unit, a conversion of a detached or attached garage, the conversion of several rooms within the Primary Unit, or a combination of converting rooms and a new addition.
An ADU must have its own living and sleeping areas and a full kitchen and bathroom. An ADU must be at least 220 square feet in total size. Maximum size varies by type of ADU.
A Junior Accessory Dwelling Unit or Jr ADU is contained entirely within the Primary Unit with the exception of adding an entrance hallway. A Jr ADU must have a separate entrance and an efficiency kitchen but may share a bathroom with the Primary Unit. The minimum size is 70 square feet and maximum size is 500 square feet.
If your lot is a legal lot of record that has an existing single family residence as the Primary Unit (or a single family residence is proposed through a separate permit request) in a residential or mixed-use zone, California State Law allows you to build one ADU and/or one Jr ADU if there are adequate water and wastewater services, minimum setback requirements are maintained, and fire and life safety standards are met. ADUs are subject to building code standards and require building permits.
Under California State Law, deed restrictions and Homeowners Associations (HOAs), as well as Conditions, Covenants, and Restrictions, and Rules and Regulations that unreasonably prevent an ADU or Jr ADU are probably not enforceable, but an HOA may require additional design standards that the City does not. The City will not intervene between an HOA and its members in interpreting State Law as it applied to any one HOA.
California State Law does not require you to reside on the property if the ADU or Jr ADU was permitted between January 1, 2020 and January 1, 2025.
Parking requirements for accessory dwelling units shall not exceed one parking space per unit or per bedroom, whichever is less. These spaces may be provided as tandem parking. The accessory dwelling unit parking space(s) may not be located in the required front yard setback.
Parking is not required in any of the following instances when the applicant demonstrates that:
- The accessory dwelling unit is located within one-half mile of public transit, including transit stations and bus stations. Distance is measured by walking distance. Distances can be calculated here. For additional up-to-date public transit information, click here.
- The accessory dwelling unit is located within an architecturally and historically significant historic district.
- The accessory dwelling unit is constructed entirely within the proposed or existing primary dwelling unit or an accessory structure.
- When on-street parking permits are required by the city but not offered to the occupant of the accessory dwelling unit.
- When there is a car share vehicle located within one block of the accessory dwelling unit.
- If a required garage, carport, or covered parking structure for the primary unit is demolished in conjunction with the construction of an accessory dwelling unit, required parking for the primary unit shall be provided on the property, outside of the front yard setback, and on a city-approved pad or structure.
State law allows conversion of non-livable space with multi-family structures (two or more units in the same structure) to one or more ADU’s. In addition, a multifamily property may add one or two newly constructed ADU’s on the property, space permitting. The total number ADU’s may not exceed 25 percent of the total of existing units. Jr ADU’s are not allowed in multifamily properties.
ADU Resources
ADU Types & Matrix
Learn about the different types of ADUs.
228.76 KB JPG | Updated 02/22/24
Building Permit Application
Download and complete the building permit application to submit with your ADU application.
533.92 KB PDF | Updated 07/16/24
ADU Plan Submittal Checklist
Download and complete the plan submittal checklist to submit with your application.
162.87 KB PDF | Updated 07/01/24
Jr ADU Plan Submittal Checklist
Download and complete the Jr ADU plan submittal checklist if you plan to construct an Jr ADU and submit it with your application.
Web Link
Expanded ADU Checklist
Download and complete the expanded ADU checklist to ensure you’ve covered all of the requirements for your plan
Web Link
SB-9 Residential Single-Family Lot Split & ADU’s
The Housing Opportunity and More Efficiency (HOME) Act
Web Link
Disclaimer
Building and Engineering may determine a project is not eligible for review based on site conditions, project scope, non-permitted construction, or other project conditions. The applicant acknowledges that preliminary review by the City of Oxnard Planning Division is required prior to plan submission.