ADUs in Orange, CA
Backyard homes for Orange, priced before you sign.
We design, permit and build standard ADU models in the City of Orange and across Orange County. You pick a model, we assess your lot, and you get one all-in price before you sign.
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The models
Four standard homes, each with a price up front.
Starting prices include design, permitting and construction with standard finishes. Site work and utilities generally run $15,000 to $35,000 and are priced after we see your lot, and city permit fees are billed at cost. Model S, Model 1 and Model 2 are all 800 sq ft or less, a size Orange always allows. See what's included.
Around Orange
Buildoly projects in Orange.
Each pin is a Buildoly project in the City of Orange. See the full map.
Orange ADU rules in plain English
What you can build in the City of Orange.
The basics for a single-family lot in Orange. Where the City's code and current state law differ, we show state law and confirm the City's approach for your address before we price anything.
How many
An ADU, a junior ADU and a detached ADU
State law lets a single-family lot have one ADU and one junior ADU inside the house, or the ADU in an existing accessory building, plus one new detached ADU of up to 800 sq ft. We confirm with the City which combination fits your lot.
Gov. Code 66323(a)Size
850 or 1,000 sq ft
An ADU with fewer than two bedrooms can be up to 850 sq ft, and one with two or more bedrooms up to 1,000 sq ft. It's also held to half the size of the existing house, but an ADU of 800 sq ft is always allowed.
OMC 17.29.050.B; 17.29.060.AHeight
16 ft detached, 25 ft attached
A detached ADU can be 16 ft tall, or 18 ft within a half mile of a major transit stop, where two more feet may be allowed to match the house's roof pitch. An attached ADU can be 25 ft or the zone's limit, whichever is lower, and two stories at most.
OMC 17.29.095.A-DSetbacks
4 ft for an ADU up to 800 sq ft
A new ADU of 800 sq ft or less needs 4 ft from the side and rear lot lines, and a conversion or a rebuild in the same place and size needs none. For a larger ADU we confirm the setbacks with the City.
OMC 17.29.080.A-BParking
One space, with exceptions
An ADU needs one space per ADU or per bedroom, whichever is less, unless it's within a half-mile walk of public transit, part of the house or an accessory building, in a historic district, or within a block of a car share space, among other exceptions. A junior ADU adds no parking.
OMC 17.29.130.A, B, DRenting and selling
Rent for more than 30 days
An ADU can be rented for a term longer than 30 days, but it can't be sold separately from the house.
OMC 17.29.120.A, DWorth knowing in Orange
A junior ADU can be up to 500 sq ft, inside the house or an existing attached garage, and needs a recorded deed restriction approved by the City Attorney.
On a lot with an existing apartment building, state law allows converting non-living space into at least one ADU and up to a quarter of the unit count, plus up to eight detached ADUs, never more than the units already there. We confirm the City's numbers for your lot.
Changing on January 1, 2027
SB 1117 limits the impact fee on an ADU over 750 sq ft to the area above 750 sq ft, in proportion to the main house, for up to two ADUs on a lot. ADUs of 750 sq ft or less still pay no impact fee.
AB 956 lets you build two new detached ADUs on a single-family lot through the state's approval path. On that path a city can cap each one at 800 sq ft.
Sources: Orange Municipal Code Chapter 17.29, as amended by Ordinance No. 20-24 (adopted July 23, 2024); California Government Code sections 66310 to 66342; SB 1117 and AB 956 (2026). Checked November 2026.
How it works
From your lot to move-in.
Step 1
Pick a model
Choose a model and finishes online, or book a free consultation to talk it through.
Step 2
Site assessment
We visit your lot, check utilities, access and the City's rules, and give you one all-in price before you sign.
Step 3
Design and permits
We finish the plans and run the permit with the City of Orange from submittal to approval.
Step 4
Build and move in
We build on site and manage the job through final inspection and your certificate of occupancy.
Typical timeline: 8 to 12 months from start to finish. About 1 month of design, 2 to 4 months of permits and 3 to 5 months of construction. Your lot and the City's review times can move it.
Orange ADU questions
What Orange homeowners ask us.
Our models start at $165,000 for Model S, $195,000 for Model 1, $270,000 for Model 2, $360,000 for Model 3. Those are all-in starting prices for design, permitting and construction. Site work and utilities generally run $15,000 to $35,000, and we price yours after the site assessment, before you sign. City permit fees are separate: your city sets them and we bill them at cost. You start with $1,000, credited in full to your contract, and many of our clients finance the whole build through our lending partners, subject to credit approval. See what's included in the price.
An ADU with fewer than two bedrooms can be up to 850 sq ft, and one with two or more bedrooms up to 1,000 sq ft. It's also held to half the size of the existing house, but an ADU of 800 sq ft is always allowed. Model S, Model 1 and Model 2 are all 800 sq ft or less. We check the exact limit for your lot.
Our typical timeline is 8 to 12 months from start to finish: about 1 month of design, 2 to 4 months of permits and 3 to 5 months of construction. Your lot and the City's review times can move it either way, and we give you a schedule for your address after the site assessment.
Usually one space per ADU or per bedroom, whichever is less. No space is needed if the ADU is within a half-mile walk of public transit, part of the house or an accessory building, in a historic district, where on-street permits are required but not offered to the occupant, or within one block of a car share space. A junior ADU adds no parking, but parking the house loses to a junior ADU has to be replaced on site.
Under state law, a junior ADU needs the owner living on site only when it shares a bathroom with the house, and we confirm how the City applies that to your plan. A junior ADU also needs a recorded deed restriction that keeps it from being sold separately from the house.
Yes. We build across Orange County, as well as Los Angeles County, San Diego and the Inland Empire. Each city has its own ADU rules and plan check, and we confirm them for your address. Enter your address in our quote tool to check that you're in our service area.
Where we build
We also build in these cities.
Each city page covers that city's ADU rules and who issues the permit. All cities.
Los Angeles County
Orange County
San Diego County
Inland Empire
See your price for an Orange ADU.
Pick a model and tell us your address. After the site assessment you get one all-in number, before you sign.