Licensed CSLB Design-Build Contractor
Junior ADU Construction in Los Angeles
A junior ADU is one of the most affordable ways to add a legal, rentable unit to your property. Capped at 500 square feet, a JADU can be created inside space you already own or built as a new unit attached to your home, and its utilities can tie directly into the main house to keep costs down. Renova Built handles design, permits, and construction under one fixed-price contract across Los Angeles, Orange, and San Bernardino Counties.
Your JADU Guide
What Is a Junior ADU (JADU)?
A junior ADU is a small, self-contained unit capped at 500 square feet, tied to a single-family home. Also called a junior accessory dwelling unit, a JADU can be carved out of space you already have, such as an attached garage, a spare bedroom, or an underused portion of your living area, or it can be built as a new unit attached to the house. Because its utilities can connect directly to the main house rather than requiring separate city connections, a junior accessory dwelling unit is one of the lower-cost paths into a legally rentable unit for many Southern California homeowners.
This page is your complete guide to junior ADU construction. You will learn how a JADU differs from a full accessory dwelling unit and an in-law unit, the California requirements that govern them, real cost ranges, when a junior accessory dwelling unit is the right choice, and how our construction process works from first visit to certificate of occupancy. Renova Built handles the entire junior accessory dwelling unit process in-house, so you have one team and one point of contact from design through final inspection.
Accessory dwelling units come in several forms, and the junior version is defined by three things: it is tied to your primary dwelling, it stays under 500 square feet, and it includes its own efficiency kitchen and entrance. A JADU can be an interior conversion or a new attached unit, and because its utilities can tie into the main house, it usually costs less than a detached ADU.
Know the Difference
JADU vs ADU vs In-Law Unit
A junior accessory dwelling unit, a regular ADU, and an in-law unit sound similar, but only two of them are legally rentable in California. Here is how they compare before you start your project.
Junior ADU (JADU)
Tied to a single-family home and capped at 500 square feet, with one JADU allowed per eligible lot. A JADU can be an interior conversion or a new attached unit. It requires an efficiency kitchen, may share a bathroom with the main house or have its own, and needs a separate exterior entrance. Owner occupancy is generally required, and its utilities can connect directly to the main house.
Regular ADU
A full accessory dwelling unit can be detached or attached and may be a new structure, reaching up to 1,200 square feet depending on local regulations, with no 500 square foot cap. It includes a full kitchen with standard appliances and its own bathroom, and it generally has separate utility connections. Owner occupancy requirements vary by jurisdiction, unlike the JADU rule.
Detached ADUs
In-Law Unit
An informal term for a room or partially converted space used by family members. An in-law unit typically lacks the permits, separate kitchen, or code compliance needed to be a legally rentable unit in California. Only permitted ADUs and JADUs qualify for legal rental use, which is why we build every in-law conversion to the JADU standard.
The practical takeaway: a junior accessory dwelling unit and a full ADU are both legally rentable when permitted, while an in-law unit usually is not until it is brought up to code. The clearest line between the two rentable options is that a full ADU can be detached and is not capped at 500 square feet, while a JADU is tied to the home and stays at or under 500 square feet. If your goal is rental income or a compliant space for family members, we build to the accessory dwelling unit JADU standard so the finished unit is fully permitted, no matter what you called it when you started.
California Rules
California JADU Requirements
California law defines a clear set of requirements for a junior accessory dwelling unit. Understanding them upfront keeps your project moving through plan check without surprises.
- Maximum size: A JADU cannot exceed 500 square feet.
- Location: It must be created within or attached to the existing single-family home, either as an interior conversion or a new attached unit. Detached structures must be permitted as ADUs, not JADUs.
- Efficiency kitchen: It must include an efficiency kitchen with a sink, a food preparation counter, storage cabinets, and a cooking facility such as a compact cooktop. A full range or oven is not required, which keeps the build simpler.
- Bathroom: A JADU may share a bathroom with the main house or have its own separate bathroom.
- Separate entrance: It must have a separate exterior entrance, independent of the main house entry.
- Owner occupancy: The property owner is generally required to live on-site, in either the primary dwelling or the JADU. Owner occupancy requirements can depend on whether the unit has its own separate bathroom, so we review your specific situation during the feasibility assessment.
- Utilities: A JADU is not required to have separate city utility connections. Its water, sewer, and electricity can connect directly to the main house, which often reduces installation costs.
- Parking: No additional parking is required for a JADU under California state law, unless you are converting a covered parking structure and your local agency requires it.
- One per lot: Only one JADU is allowed per eligible single-family lot.
Efficiency Kitchen
What Counts as an Efficiency Kitchen
The efficiency kitchen is the feature that most often trips up a junior ADU at inspection, so it is worth getting right. California building code requires a JADU to include a food preparation area with a sink, a food preparation counter, storage cabinets, and a cooking facility. The cooking facility can be a compact cooktop or a similar appliance rather than a full range, which is one reason a junior accessory dwelling unit stays affordable.
We design each efficiency kitchen to make the most of the square feet available within the 500 sq ft limit, pairing the food preparation counter and storage cabinets so the space feels like a real home rather than a hotel room. Because the kitchen can tie into the main house plumbing in most conversions, we can keep costs down while still delivering a fully independent living space.
Conversion Types
Our Junior ADU Construction Services
Every property is different, and so is every JADU project. These are the most common JADU builds we handle, each built to meet California building code and your city’s local regulations.
Garage Conversion JADUs
An attached garage is often the most straightforward path to a JADU. We convert garages up to 500 sq ft into a fully independent living space with an efficiency kitchen, a separate entrance, insulation, HVAC, and utility connections. Garage conversion work typically includes slab evaluation, structural reinforcement where needed, and fire separation compliance. When your local agency requires replacement parking, we address it during planning so there are no surprises at permit review.Interior Space Conversion JADUs
Spare bedrooms, bonus rooms, or an underused portion of your existing living area can become an independent unit with a kitchenette, a separate exterior entrance, and a shared or private bathroom. Converting a room within the existing primary residence carries the lowest construction cost of any JADU type, because the basic shell, wiring, and sometimes plumbing are already in place. We configure the bathroom arrangement around your budget and owner occupancy goals.New Attached JADUs
A JADU can also be built as a new unit attached to your home rather than carved from existing space. We add a code-compliant attached unit within the 500 sq ft limit, with its own efficiency kitchen and separate entrance, and tie its utilities into the main house. This path suits property owners who do not have interior space to give up but still want the lower utility and permitting costs of a JADU over a full attached or detached ADU.Not sure which path fits your home? A detached ADU or a full attached ADU may be the better choice if you need more than 500 square feet. Compare your options against our detached ADU guide, or start with the full ADU construction overview to see every configuration side by side.
Cost Overview
How Much a Junior ADU Costs
A junior ADU is often the lowest-cost accessory dwelling unit you can build, because it can reuse existing space and tie utilities into the main house. These are typical ranges, not a fixed quote.
| Conversion type | Typical JADU range |
|---|---|
| Room conversion with new separate bathroom | $110K to $150K |
| Attached garage conversion, full compliance | $150K to $200K |
| Attached unit (new construction) | $160K to $210K |
| Junior ADU (JADU) overall range | $110K to $200K |
Your final pricing depends on site conditions, the finishes you choose, and permit fees. An interior JADU that divides existing space is usually the lowest-cost path, while a new attached JADU can approach the cost of a full attached ADU. A detached ADU typically runs $180K to $390K depending on size. JADUs also generally avoid the development impact fees that larger units can trigger, and because a JADU’s utilities can connect directly to the main house, you can save on separate meter and connection costs. Cost drivers include electrical upgrades, plumbing access, insulation required under Title 24, and how much of the efficiency kitchen has to be built from scratch. For the full picture, see our ADU cost guide, and to fund the build, our ADU financing overview walks through the options.
Right Fit
When a JADU Is the Right Choice
A junior accessory dwelling unit is not the answer for every property, but it is the smart move in several common situations. It makes the most sense when the numbers and your site conditions line up with what a JADU does best: adding a compact unit at a lower entry cost, whether by converting existing space or attaching a small new unit.
- You have space to convert already, such as an attached garage, a large bedroom, or an existing accessory structure, or room to attach a small new unit without a full detached build.
- You want rental income at a lower entry cost and prefer to invest in the JADU range rather than the higher cost of a full-size detached ADU.
- Your lot has constraints, such as setback requirements or lot size limits, that make a detached ADU difficult or impossible to build.
- You are comfortable with the owner occupancy clause, or you plan to include a separate bathroom so the arrangement fits your goals under current ADU laws.
- You want faster completion, since JADU projects typically finish in 3 to 6 months rather than the 8 to 14 months a detached ADU can take.
Why Renova Built
One Team, One Contract for Your JADU
Choosing the right builder for a junior accessory dwelling unit means finding a team that understands both the construction and the specific legal framework that separates a JADU from a standard ADU. Renova Built is a licensed, bonded, and insured design-build contractor, CSLB Class B License #1149349, bonded under Bond #67750133, based in Sherman Oaks and serving Los Angeles, Orange, and San Bernardino Counties. Every JADU project runs through one in-house team.
- A single contract with no coordination headaches, so your project does not stall between handoffs between separate firms
- Deep JADU expertise across the 500 square feet size cap, efficiency kitchen requirements, and owner occupancy rules, so your unit is compliant from day one
- A lower-cost path to rental income, since a JADU can reuse existing space or tie utilities into the main house rather than requiring separate connections
- Permit management with the community development department in each city we serve, which keeps plan check moving
- Free consultations with detailed cost estimates, a zoning review, and a feasibility assessment, with no obligation
How It Works
Our JADU Construction Process
Building a JADU is simpler than constructing a detached ADU, but it still takes precise coordination between design, permitting, and construction. We manage every phase under one roof.
1
Free Consultation and Feasibility Assessment
We visit your property to evaluate the existing space, whether that is an attached garage, a bedroom, or another room, and discuss your goals. We review local zoning requirements, explain how owner occupancy applies to your situation, and provide a detailed cost estimate and a realistic timeline for your specific project.2
Design, Plans, and Permitting
Our in-house design team creates 3D plans optimized for your space within the 500 sq ft maximum. We prepare Title 24 energy compliance documentation, permit applications, and supporting materials, then submit to your local agency and manage the entire plan check process, including corrections and resubmittals, so you skip the trips to the building department.3
Construction
Construction covers everything a fully independent living space needs: an efficiency kitchen with a food preparation counter, storage cabinets, and a cooking facility; a bathroom upgrade or a new separate bathroom; electrical, plumbing, and HVAC work; insulation; and a code-compliant separate entrance. You get progress updates at each milestone.4
Final Inspection and Certificate of Occupancy
After construction, we schedule the final city inspection and obtain your certificate of occupancy, so the unit is legally ready for rental income or family. We walk you through the finished, permitted JADU before we hand over the keys. For the fee and approval details, see our ADU permits guide.
Project Examples
Recent Junior ADU Projects
Illustrative examples of the junior ADU conversions we build across Southern California. Costs are typical for the conversion type and depend on site conditions, finishes, and permit fees.
Sherman Oaks Garage Conversion
A 450 sq ft JADU with an efficiency kitchen, a separate bathroom, and a new exterior entrance, converted from an attached garage. Typical for this type: completion in about four months from permit approval, at the mid-to-upper end of the JADU cost range once a full bathroom is added.
Irvine Bedroom Conversion
A 400 sq ft interior JADU with a kitchenette and shared bathroom access, carved out of an existing bedroom. This is the lowest-cost path, at the lower end of the JADU range, letting the property owner add rental income without the expense of a detached ADU.
San Bernardino County Workshop
A 500 sq ft JADU with separate sanitation facilities, a full insulation upgrade, and new HVAC, converted from an attached workshop. Because it includes its own separate bathroom, the owner occupancy arrangement worked out well for the property owner’s plans.
Service Areas
Junior ADU Construction Across LA, OC, and San Bernardino
Based in Sherman Oaks, we build ADUs and JADUs across Los Angeles County, Orange County, and San Bernardino County. Each jurisdiction has its own local regulations and review timelines, and our team knows the community development requirements in the cities we serve, which means fewer revision rounds and faster approvals.
Free ADU Consultation
Start Your JADU Project Today
Find out whether a junior accessory dwelling unit is the right fit for your property and your goals. Tell us about your home and we will reach out, usually within one business day, to walk you through your options and a transparent, fixed-price estimate. No pressure, no obligation. Call (818) 968-2981 or send your details.
Junior ADU FAQ