BOSS Homes ADUs for Orange County homeowners
Orange County is where we have built some of our most straightforward homeowner projects, and it is close enough to our Montebello factory that delivery is a short run down the 5 or the 57.
We manufacture the wall and roof panels, we hold the contract, and our own crew assembles on your lot. There is no handoff between a factory and a separate builder.
LOCAL RULES
What you can build in Orange County
The framework is set by state law and applies the same way in Irvine as it does in Anaheim. A city cannot require more than four feet from your side and rear property lines, cannot set a minimum lot size, cannot require you to live on the property, and has to approve a compliant application ministerially rather than putting it to a hearing. State law also guarantees you the ability to build at least 800 square feet even where local lot coverage or floor area rules would otherwise block it.
What varies in Orange County is which counter you walk up to. There are thirty four incorporated cities here, and each runs its own building department with its own portal, its own fee schedule and its own queue. A homeowner in Buena Park and a homeowner in Mission Viejo are following identical state rules through two completely different offices. If your property is in an unincorporated pocket, you are with OC Development Services instead.
Several jurisdictions in the county maintain pre-approved or standard ADU plan libraries intended to shorten plan check. We do not own a pre-approved plan of our own, but we can build a city pre-approved plan in the BOSS system, which gives you a layout that has already been through review together with our construction. The floor plan and room sizes stay as drawn and the roofline is the main thing that changes. Whether the department still treats the converted plan as pre-approved varies city to city, so we establish that early rather than after a design is drawn.
Two site conditions come up often here. Coastal zone properties carry an additional layer of review, which affects the cities along the southern half of the county. And a number of the older inland neighborhoods sit on lots where the usable rear yard is smaller than the county averages suggest, which is a design question rather than a legal one.
Thirty four cities, one set of rules
The substance of what you can build does not change between Anaheim and San Clemente, because the state sets it. What changes is the department, the fee schedule and how long the queue is. Establishing which jurisdiction you are actually in is the first thing we do, and getting it wrong is what costs people weeks.
WHAT WE BUILD
ADUs for Orange County lots
Eight models, studio through three bedroom. Every one adapts to your lot and to the house it sits behind.
One bedroom, 360 to 500 sq ft
Rendering. One Bed Plus, 16' x 32'.
BEST FOR: THE STANDARD POSTWAR TRACT LOT
Most of Orange County was built out in the postwar decades on regular rectangular lots with a real rear yard, and a one bedroom sits on that shape comfortably without crowding the main house. It is the size that works both for a family member moving in and for a long term tenant, which is why it is the one we are asked about most here.
- One Bed Core at 16′ x 24′, One Bed Plus at 16′ x 32′
- Separate bedroom, full bath, walk-in closet on the Plus
- From $142,495 installed, including civil work and assembly
Two and three bedroom, 750 to 1,200 sq ft
Rendering. Two Bed Core, 20' x 40'.
BEST FOR: LARGER PARCELS AND HOMES THAT ALREADY FILL THEIR
LOT
We added a detached ADU to a home of 2,845 square feet in Buena Park, on a lot that already had a full sized house on it. That is the common Orange County situation, and on the larger parcels in Yorba Linda, Villa Park and the eastern foothills a two or three bedroom unit is comfortably within reach.
- Three two bedroom layouts, one three bedroom
- Two full bathrooms on most configurations
- From $228,395 installed, including civil work and assembly
Studios, 220 to 320 sq ft
Rendering. Studio Core, 10' x 24'.
BEST FOR: THE COASTAL CITIES WHERE LAND COSTS MOST
In Newport Beach, Laguna and the beach cities, lots are tight and every square foot of yard is expensive. A studio takes the smallest bite out of the garden, keeps the build inside the shortest permitting path, and still delivers a full kitchen and bathroom.
- Studio Core at 10′ x 24′, Studio Plus at 12′ x 28′
- Full bathroom and kitchen in both
- From $110,695 installed, including civil work and assembly
HOW IT IS BUILT
Seven trades, one panel
Our wall and roof panels are manufactured in Montebello with framing, sheathing, insulation and the electrical and plumbing rough-ins already integrated. Light gauge steel framing around a PIR insulation core, cement board outside, drywall inside, so the finished room feels like any other room in your house. Your panels are being built in the factory while your foundation and utilities go in on site, rather than one after the other. ASTM E84 Class A fire rating, meets Wildland Urban Interface requirements, evaluated under IAPMO UES ER-0658.
WHAT PEOPLE SAY
Homeowners, cities and builders
Overall we had an amazing experience working with BOSS. Delivery deadline was met to avoid any delays with our project deadline, with very detailed direction in regard to assembly.
Bernardo Navarrete, City of Baldwin Park
I’m glad I chose BOSS Homes for my tiny house. They delivered a high-quality product at a fair price, and their team was knowledgeable, responsive, and easy to work with.
Paul Meredith, Homeowner
The BOSS system has been intelligently and strategically designed so the site assembly was remarkably simple.
Michael Waters, Swinerton Builders
Areas we serve
We build across the county, including Anaheim, Santa Ana, Irvine, Huntington Beach, Garden Grove, Fullerton, Orange, Costa Mesa, Mission Viejo, Westminster, Buena Park, Tustin, Yorba Linda, Lake Forest, Newport Beach, Laguna Niguel, La Habra, Fountain Valley, Placentia, Brea, Cypress and Los Alamitos.
Questions
Common questions in Orange County
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Which city department handles my ADU permit?
Whichever city your property sits in. Orange County has thirty four separate cities, each with its own building department. Unincorporated areas go through OC Development Services. We identify the right agency at the start.
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Are the rules different in each Orange County city?
Less than people expect. The substance is set by state law and is the same everywhere. What differs is the process, the fee schedule and how long the queue is.
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Do coastal properties have extra requirements?
Properties within the coastal zone carry an additional review layer. It does not prevent an ADU, but it needs to be factored in at the start rather than discovered later.
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Can I put an ADU on a lot that already has a large house?
Yes. We did exactly that in Buena Park, on a lot with a 2,845 square foot home already on it.
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Do you build to match my existing house?
Within the panel system, yes. Colors, siding, window and door placement and roofline are adjustable. We matched an existing Cliff May ranch this way.
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How much does an ADU cost in Orange County?
Our models start at $110,695 for a 220 square foot studio and run to $368,895 for a 1,200 square foot three bedroom, as typical installed prices including civil work and assembly. Your site determines the final number.
No cost, no obligation
See what fits on your lot
Tell us where the property is and we will call you back to talk through what is possible.
Or call us now on 1-888-634-0338
