Building an ADU in Orange
The City of Orange is known for its historic Old Towne, tree-lined streets, and mature neighborhoods with deep lots and original garages. Those lots are a good fit for an ADU, whether you want a rental unit, a place for family, or flexible space of your own. Lamarc Prime Builders designs and builds ADUs for Orange homeowners and plans around the city’s detailed design standards, which cover everything from exterior materials and colors to window trim and rooflines, as well as extra care for properties in historic districts. We take your project from first sketch through permits and final inspection.
ADU Services Available in Orange, CA
Our ADU services in the City of Orange focus on early planning and clean execution. We help homeowners evaluate what’s allowed on their property, align the design with local requirements, and move through permits and construction with a clear, organized process.
✅ Detached & Attached ADUs
✅ Garage Conversion ADUs
✅ Junior ADUs (JADUs)
✅ ADU Planning & Design Coordination
✅ Permits, Plan Submittals & City Revisions
✅ Construction, Inspections & Final Completion
A free site evaluation is the best way to understand your options and plan the next steps with confidence.
ADU Rules in Orange
ADUs allowed per lot
1 ADU + 1 JADU on a single-family lot
Max detached ADU size
850 sq ft (studio or 1 bedroom); 1,000 sq ft (2+ bedrooms); at least 800 sq ft always allowed
Max attached ADU size
Up to 50% of the existing home (at least 800 sq ft allowed)
Max JADU size
150 to 500 sq ft
Max height (detached)
16 ft (18 ft near major transit) + up to 2 ft for roof pitch
Two-story ADU
Attached ADUs up to 25 ft or your zone's limit, max two stories
Setbacks
4 ft side and rear for ADUs of 800 sq ft or less; larger ADUs follow your zone
Space between buildings
Per the city's residential zoning standards; we confirm for your lot
Parking
1 space per ADU; none near transit, in historic districts, or for conversions
Owner occupancy
Generally not required for an ADU under state law; JADU requires the owner on site
Short-term rental (Airbnb)
Rentals must be over 30 days; no Airbnb
Impact fees
None under 750 sq ft; larger ADUs pay proportionally
Pre-approved plans
We check for city-approved plans for your property
Permit review
Two steps: ADU application with Community Development, then building permit
Approval timeline
60 days for the ADU application
Local insight
Orange has detailed objective design standards, from exterior materials to window trim and rooflines. ADUs in Old Towne and other historic districts must also follow the historic design standards.
How ADU Permitting Works in Orange
Orange has a two-step process. You first submit the city’s ADU application form to Community Development with a fee that follows the Administrative Design Review schedule. The review is ministerial, which means no hearing and no discretionary review, and the city must decide within 60 days of a complete application. After approval, you apply for a building permit, and plan check timelines are the same as for similar construction.
Each new ADU needs its own street address assigned by Public Works. Fire sprinklers are required for the ADU only if the main home requires them, and fire and safety staff may require extra setbacks in some areas.
Property feasibility review
Review zoning, lot conditions, access, utilities, and applicable ADU requirements.
ADU design and preparation
Prepare the site plan, architectural drawings, engineering, and required supporting documents.
City plan review and approvals
Submit the application, coordinate with city departments, and respond to plan-check corrections.
Permit issuance and construction
After approval and permit issuance, proceed with construction and required inspections.
FAQs
What design standards does Orange require for ADUs?
Orange has detailed objective standards. New ADUs need at least two exterior materials and two colors, at least three design features such as eaves or trellises, trim around windows and doors, and wall variation so no long flat plane faces the street. The roof must match the main home’s form and pitch where feasible. We design to these standards from the start.
I live in Old Towne or a historic district. Can I still build an ADU?
Yes. ADUs are allowed in historic districts, and parking is not required. The ADU has to meet the applicable historic design standards, and garage doors on contributing structures must be preserved in place and made inoperable rather than removed.
How big can an ADU be in Orange?
Up to 850 sq ft for a studio or one bedroom and 1,000 sq ft for two or more bedrooms, and up to 50% of your existing home. At least 800 sq ft is always allowed. Conversions of existing space can keep their current size plus up to 150 sq ft for entry and exit.
Do I need to provide parking for an ADU in Orange?
Often not. No parking is required within a half-mile walk of public transit, in a historic district, for ADUs inside your existing home or an accessory structure, or when permit parking isn’t offered to the occupant. Otherwise one space is required, and tandem parking in the driveway is allowed.
Can I rent my Orange ADU on Airbnb?
No. Rentals must be longer than 30 days, so short-term rentals are not allowed. Long-term tenants and family members are fine.
What are the steps to get an ADU approved in Orange?
First you submit the city’s ADU application to Community Development, which is reviewed ministerially within 60 days of a complete application. After approval, you apply for a building permit and go through plan check. Each ADU also needs its own address from Public Works.
