There are three kinds of accessory dwelling unit, and which one your lot suits decides almost everything about the budget. Remodeling Beverly Hills designs and builds all three across Beverly Hills and the Los Angeles Westside: detached backyard units, attached additions with their own entrance, and junior ADUs carved out of existing floor area.
California's state ADU statutes override a great deal of local zoning, which is precisely why these are buildable on lots where a conventional addition is not. Call (424) 766-1835 and we will tell you which category your property fits and what it can hold.
The three ADU categories, and why the distinction matters
Detached ADU
A freestanding building in the rear yard. State law protects a minimum four-foot rear and side setback and permits at least 800 square feet at 16 feet in height regardless of local floor area limits. This is the most flexible category and the most expensive per square foot, because it needs its own foundation, roof, and utility connections.
Attached ADU
An addition to the main house with a separate exterior entrance, its own kitchen and its own bath. Cheaper than detached because it shares a wall, a roof line and often a utility trench, but it has to be independent. A bedroom suite with a wet bar is not an ADU.
Junior ADU
Up to 500 square feet converted from existing space inside the main house, typically a bedroom with an exterior door added. A JADU may share a bathroom with the main house and needs only an efficiency kitchen. It is by far the cheapest route to a legal second unit and the most commonly overlooked.
What actually drives ADU cost
Los Angeles ADU pricing in 2026 sits at roughly $300 to $450 per square foot for new detached construction, putting a typical unit somewhere between $219,000 and $459,000. Garage conversions run lower, around $250 to $400 per square foot.
Very little of that spread is finish level. The variables that actually move an ADU budget are the distance from the main house to the new unit, because every foot of that trench carries water, sewer, gas, electrical and sometimes fire sprinkler line; whether the existing electrical service has capacity or the main panel needs upgrading; whether the site slopes, which decides between a simple slab and a stepped foundation or caissons; and whether a fire sprinkler system is required, which usually follows from whether the main house has one.
| ADU type | Typical size | Typical range |
|---|---|---|
| Junior ADU, interior conversion | 300-500 sq ft | $85,000-$160,000 |
| Garage conversion ADU | 240-480 sq ft | $95,000-$195,000 |
| Attached ADU | 400-750 sq ft | $180,000-$340,000 |
| Detached ADU, new construction | 600-1,200 sq ft | $219,000-$459,000 |
Based on Los Angeles County construction costs as of 2026. Excludes school and utility connection fees. Estimates only.
Utilities, parking and the questions owners ask late
State law prohibits requiring replacement parking when a garage is converted to an ADU, and it prohibits requiring a new separate utility connection for an ADU created within an existing structure. A new detached ADU may be required to have its own connection, and whether you want a separate meter is a genuine decision rather than a formality. Separate metering makes tenant billing clean and adds cost up front.
Sewer capacity is the constraint people meet last. An older four-inch lateral serving a single-family house may need upsizing to carry a second dwelling, and that is a trench across the front yard and into the street. We check the lateral before design rather than after.
An ADU cannot be sold separately from the main house in most circumstances, and short-term rental of under 30 days is generally prohibited for ADUs. Build the pro forma on a long-term tenancy.
ADU timeline
Design and engineering runs six to twelve weeks. Plan check for a standard-plan ADU is often quicker than a comparable addition, because state law imposes review deadlines on the agency. Construction is four to seven months for a detached unit, two to four for a conversion.
Realistically, from first meeting to a tenant with keys, plan on nine to fifteen months for a new detached ADU.
Talk to a Beverly Hills remodeling contractor
On-site estimate, straight answers on budget and schedule, and a written scope before anyone swings a hammer.
Call (424) 766-1835Frequently asked questions
Can I build an ADU on my Beverly Hills lot?
Most single-family lots can accommodate at least one ADU under state law, and many can add a junior ADU as well. The practical limits are usable rear-yard area, site slope, and whether utilities have capacity. We check all three before design.
How much does an ADU cost in the Beverly Hills area?
Roughly $300 to $450 per square foot for new detached construction as of 2026, which puts most units between $219,000 and $459,000. Garage conversions run $95,000 to $195,000 and junior ADUs less again.
Do I need extra parking for an ADU?
Generally no. State law bars parking requirements for ADUs within a half mile of public transit and prohibits requiring replacement parking when a garage is converted. Most Beverly Hills parcels qualify on the transit proximity test.
Can I rent the ADU on Airbnb?
No. Rentals under 30 days are generally prohibited for accessory dwelling units, and Beverly Hills restricts short-term rentals separately. Underwrite it as a long-term rental.
Will an ADU raise my property taxes?
The ADU itself is assessed and added to your tax base, but building one does not reassess the existing house. In practice the increase is proportional to the new construction value, not to the whole property.