Accessory Dwelling Units (ADU) Information

ADU Information and FAQs

ACCESSORY DWELLING UNIT (ADU) AND JUNIOR (Jr) ACCESSORY DWELLING UNIT
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 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 highly recommended and encouraged.

What is an ADU?
ADUs go by many names. The State of California and the City of Oxnard refer to them as Accessory Dwelling Units, but they are also commonly referred to as “second units,” “granny flats,” “in-law suites,” “tiny homes” and / or “cottages.” 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.

What is a Jr 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.

Can I build an ADU and Jr ADU on my property?
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.

Find your zone here

What if my lot is deed restricted or my HOA does not allow ADUs?
Under California State Law, deed restrictions and HomeOwners Associations, 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.

Must I live on the property?
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.

Do I have to provide parking for an ADU?
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.

What if I have an existing ADU that is in violation of building codes?
An owner may request a five-year delay in enforcement of the building codes, which will be granted unless the violation impacts health and safety requirements.

ADU in a Multi-family 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.

How To Get Started

1)  UNDERSTAND the ADU TYPES and the ADU MATRIX
The City of Oxnard has defined ADU “TYPES” and prepared detailed development standards for six TYPES of single-family ADU’s, one multi-family, and one type of mixed-use as shown in the table below. A summary ADU TYPE MATRIX  provides development standards for all ADU Types.  

2)  IDENTIFY AN ADU TYPE, Jr ADU, OR MULTI-FAMILY ADU
Use the ADU Matrix to identify which ADU TYPE you seek to permit.   If you have questions, contact Planning staff.

3) SUBMIT THE ADU WORKSHEET WITH THE BUILDING PERMIT
Click here for ADU Building Permit Information.