Oxnard, CA Accessory Structures: ADU Rules (2026)
ADU rules in Oxnard, CA, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.
Key Facts
- Detached ADU height limit
- Two stories, 25 feet
- Detached ADU size limit
- 850 sq ft (1BR) / 1,200 sq ft (2BR+)
- Attached ADU size limit
- 1,200 sq ft or 50% of house
- Side/rear setback
- Minimum four feet
- Parking
- One space per ADU, many exemptions
- Approval timeline
- 60 days (30 for preapproved plans)
Summary
Oxnard's zoning code lets any single-family lot add one internal or attached ADU plus one junior ADU, and a separate detached ADU besides, all approved ministerially with no discretionary hearing under Municipal Code Section 16-465 et seq. Detached ADUs are capped at two stories and 25 feet, with four-foot side and rear setbacks, and multi-family lots can add up to eight detached units. Homeowners association covenants cannot block construction.
(A) Maximum size. (1) The maximum size of a new attached ADU may not exceed 1,200 square feet or 50% of the total floor area, including attached accessory buildings or structure, of the primary single-family unit, whichever is less... (2) The maximum size of a detached ADU determined by gross floor area of living space is as follows: (a) 850 square feet of interior livable space, if one bedroom or less; (b) 1,200 square feet of interior livable space, if more than one bedroom... (C) Maximum height. (1) The maximum height for attached and detached shall not exceed two stories and 25 feet... (D) Setbacks. (1) The front yard setback is the same as the underlying zone. (2) The minimum of four feet for rear and side yard setbacks.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Contains Supplement current through 1-26-2026).
Full Breakdown
3. 4, a single-family lot may add one internal or attached ADU plus one junior ADU, and separately one detached ADU; a multi-family lot may convert non-livable space into at least one internal ADU (up to 25% of existing units) and add up to eight detached ADUs, capped at the number of existing units, or two detached ADUs where the multi-family building is only proposed. 7 sets a maximum attached ADU size of 1,200 square feet or 50% of the primary unit's floor area, whichever is less, and a detached ADU maximum of 850 square feet for a studio or one-bedroom, or 1,200 square feet for more bedrooms.
Height is capped at two stories and 25 feet, the front setback matches the underlying zone, and rear and side setbacks are a minimum of four feet. 9 requires one parking space per ADU, tandem parking permitted, but waives parking entirely within a half-mile of transit, in historic districts, for conversions of existing structures, or when a car-share vehicle sits within one block. 2. A variance from any of these standards requires planning commission review under Sections 16-565 to 16-569 rather than staff-level sign-off.
Violations & Fines
Constructing an ADU without a building permit exposes the owner to standard city code enforcement, including stop-work orders, under the building and zoning codes. An ADU or JADU built without permits before January 1, 2020 is not subject to demolition but may be legalized under Cal. Gov't Code Section 66311.7. A denied or incomplete application must receive written comments identifying the specific defect under Section 16-465.2(A)(3)(a), and any request to deviate from the numeric standards goes to the planning commission for a variance under Sections 16-565 to 16-569.
Frequently Asked Questions
How many ADUs can I build on a single-family lot in Oxnard?
Do I need a public hearing to build an ADU in Oxnard?
What is the tallest detached ADU I can build in Oxnard?
Can my HOA stop me from building an ADU?
Sources & Official References
Other rules in Oxnard
How Oxnard compares: Easiest Cities to Build an ADU·California rules heatmap·Compare Oxnard to another location·View the California accessory structures overview
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