County of Orange ADU regulations

Zoning

All properties zoned for single-family and multi-family use may be eligible to build ADUs.

Number of ADUs

Depends on how your lot is zoned.

• Lots zoned for single-family use may add 1 ADU and 1 Junior ADU (JADU).
• Lots with an existing multi-family building may add up to 8 detached ADUs (no more than the number of existing units) plus conversion ADUs in non-livable space, at least one and up to 25% of the existing units. Lots with a proposed multi-family building may add up to 2 detached ADUs. (State law since January 2025; some local codes have not caught up, and state law controls.)

Building size

Maximum floor area by ADU type.

Building height

Maximum height by ADU type.

Setbacks

Minimum distance from property lines.

Parking

California state law.

No parking is required for an ADU if any of the following is true:

• The ADU is within one-half mile walking distance of public transit.
• The ADU is within an architecturally and historically significant historic district.
• The ADU is part of the proposed or existing primary residence or an accessory structure.
• On-street parking permits are required but not offered to the ADU’s occupant.
• A car-share vehicle is located within one block of the ADU.
• No replacement parking is required when a garage, carport or uncovered parking space is removed or converted to build an ADU (expanded by SB 1211, 2025).