ADU in Los Angeles, CA
Junior ADU & Interior Conversion in Los Angeles turns existing square footage, attached to your main house, into permitted rental space without adding new foundation. Because Los Angeles’s 1920s-1950s bungalows in West Adams, Leimert Park, and Highland Park already have basements, garages, and spare rooms attached to the primary structure, these conversions skip the most expensive line items. Call (424) 407-8266 to schedule your free estimate.
We’re a design-build studio, not a designer who hands off to a contractor. The drawings, the permit set, and the construction live under one contract at one written price. Since 2015, we’ve completed 900+ ADUs, and every one started with a written quote before any work began.
Why Los Angeles Homes Are Different
Los Angeles is the single largest ADU market in the United States. The city permitted more ADUs than any other jurisdiction in the country, and it created its own Standard Plan Program offering pre-approved blueprints that compress LADBS permitting timelines from months to weeks. Homeowners here have a faster, cheaper path to a permitted ADU than almost anywhere else in America.
The housing stock shapes what’s possible. West Adams, Jefferson Park, and Echo Park are dense with 1920s-1950s bungalows and Craftsmans on R1 lots, most with a detached single-car garage along an alley. That makes garage conversion the dominant project type. Post-war ranch homes across the San Fernando Valley, Reseda, Canoga Park, and Van Nuys offer larger rear yards but often need electrical panel upgrades and updated sewer laterals.
The mild Mediterranean climate eliminates freeze-protection concerns, but roughly a third of residential hillside neighborhoods, Hollywood Hills, Laurel Canyon, Bel Air, and Chatsworth, sit inside CalFire-designated Very High Fire Hazard Severity Zones. Those zones impose additional requirements: ember-resistant vents, Class A roofing, and non-combustible exterior cladding that add meaningful cost.
Our Main Los Angeles Services
Los Angeles homeowners call us most often for these three services, each with its own Los Angeles page and pricing:
ADU Design & Permitting in Los Angeles
We produce the full permit set, structural calculations, and LADBS submittal for custom and Standard Plan ADUs. In Los Angeles, we pre-screen every lot against the Standard Plan Program’s slope, lot coverage, and setback rules before quoting, because a hillside lot in Silver Lake that fails those rules sends the project back to full custom. ADU Design & Permitting in Los Angeles
Garage Conversion ADU in Los Angeles
We convert existing garages into permitted living space, handling slab evaluation, wall framing, utility tie-ins, and final inspection. Most Los Angeles conversions involve 1920s-1950s single-car structures along alleys in Leimert Park or Highland Park, where the existing slab and roof structure determine whether the project qualifies as a straight conversion or needs partial rebuild. Garage Conversion ADU in Los Angeles
New Detached ADU in Los Angeles
We design and build standalone units from foundation to final inspection, including prefab coordination with brands like Abodu and Cover. In Los Angeles, new detached ADUs on hillside lots in Hollywood Hills or Laurel Canyon trigger CalFire requirements that flat Valley lots avoid, so we verify fire zone status before the permit set is drafted. New Detached ADU in Los Angeles
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
Junior ADU & Interior Conversion in Los Angeles
Junior ADU & Interior Conversion in Los Angeles creates a separate dwelling unit inside your existing home footprint, attached to and smaller than the primary residence. In Highland Park and Echo Park, we regularly convert underused basements, spare bedrooms, and above-garage spaces into 500-square-foot rentals with kitchenettes and exterior entrances, working within the original structure to avoid new foundation costs. Junior ADU & Interior Conversion covers every interior project type we handle.
These projects move faster than detached builds because they use existing walls and roofs, but they still need full LADBS permit sets, Title 24 energy compliance, and separate utility metering or load calculations. The Haven Standard Clause 1 locks the written price before any work starts.
Basement ADU
Signs you need it
Your basement has 7.5+ feet of finished ceiling height, exterior access or window egress, and you’re not using the square footage.
What it costs in Los Angeles
Basement ADU conversions in Los Angeles typically run $85,000-$150,000 all-in, drawings through final inspection, depending on moisture remediation and egress window installation.
How we do it
We test for moisture intrusion, design the egress and ventilation plan, produce the LADBS permit set, then frame, insulate, and finish to code.
Above-Garage ADU
Signs you need it
Your garage has a structurally sound roof deck with 8+ feet of clearance, and the garage below remains in use.
What it costs in Los Angeles
Above-garage ADUs in Los Angeles typically run $95,000-$175,000 all-in, including structural reinforcement, stair access, and utility routing.
How we do it
We verify joist capacity, design stair and utility runs, permit through LADBS, then build out the unit with fire separation between garage and living space.
What Junior ADU & Interior Conversion Costs in Los Angeles
| Item | Typical range in Los Angeles |
|---|---|
| Basement ADU conversion | $85,000 - $150,000 |
| Above-garage ADU | $95,000 - $175,000 |
| Room-to-ADU conversion | $75,000 - $130,000 |
Does a Junior ADU need its own kitchen and bathroom in Los Angeles?
Yes, LADBS requires a kitchenette with cooking facilities and a separate bathroom for Junior ADU approval. We design these into compact layouts, often 300-500 square feet.
Can I rent my Junior ADU in Los Angeles?
Yes, state law prohibits owner-occupancy requirements for Junior ADUs permitted after 2020. Call (424) 407-8266 for an exact quote on your interior conversion.
ADU Site Prep & Utilities in Los Angeles
ADU Site Prep & Utilities in Los Angeles solves the infrastructure gap between an approved permit set and a buildable site. In Reseda, Canoga Park, and Van Nuys, 1950s-1970s ranch homes often have 100-amp electrical panels and original clay sewer laterals that cannot support a second dwelling unit. ADU Site Prep & Utilities handles everything below the finish layer.
We coordinate these trades under the same single contract as the ADU build, so the electrician who upgrades your panel is accountable to the same written price and schedule as the crew pouring the foundation.
Electrical Panel Upgrade
Signs you need it
Your main panel is 100 amps or less, has no open breaker slots, or the utility lateral is undersized for a second meter.
What it costs in Los Angeles
Electrical panel upgrades in Los Angeles typically run $4,500-$12,000, including LADBS permit, LADWP coordination, and new 200-amp service.
How we do it
We pull the LADBS electrical permit, coordinate LADWP service upgrade, install the new panel, and pass inspection before rough-in begins.
Plumbing Lateral
Signs you need it
Your home has original clay or cast-iron sewer lateral, frequent backups, or the ADU location is beyond 25 feet from the main sewer line.
What it costs in Los Angeles
Sewer lateral replacement in Los Angeles typically runs $8,000-$18,000, depending on trench length, street-to-house distance, and LADWP street restoration requirements.
How we do it
We camera the existing line, permit through LADBS and Bureau of Sanitation, trench or trenchless replace, then pressure-test and pass final.
What ADU Site Prep & Utilities Costs in Los Angeles
| Item | Typical range in Los Angeles |
|---|---|
| Electrical panel upgrade | $4,500 - $12,000 |
| Sewer lateral replacement | $8,000 - $18,000 |
| Foundation and grading (new detached) | $15,000 - $35,000 |
Does LADWP require a separate meter for my ADU in Los Angeles?
Separate electric meters are allowed but not required; we size the panel and service for either configuration during design. Call (424) 407-8266 to review your utility layout.
How long does site prep take before construction starts in Los Angeles?
Utility upgrades typically add 3-6 weeks before rough-in, with LADWP and Bureau of Sanitation scheduling the longest lead times.
Brands We Service in Los Angeles
We specify and coordinate prefab and modular systems from Abodu, Cover, Dvele, and James Hardie within our single-contract model. Parts and replacement panels are stocked through Los Angeles distributors, so warranty repairs don’t wait on cross-country shipping. our brands
Pricing for ADU in Los Angeles, CA
| Service | Typical range in Los Angeles |
|---|---|
| Junior ADU & Interior Conversion (basement) | $85,000 - $150,000 |
| Junior ADU & Interior Conversion (above-garage) | $95,000 - $175,000 |
| Junior ADU & Interior Conversion (room conversion) | $75,000 - $130,000 |
| Electrical panel upgrade | $4,500 - $12,000 |
| Sewer lateral replacement | $8,000 - $18,000 |
| Foundation and grading (new detached) | $15,000 - $35,000 |
Hillside lots in CalFire zones, Hollywood Hills, Laurel Canyon, or Bel Air, add 10-25% for fire-resistant materials and additional inspections. Every figure above is paired with a written price before work starts, per Haven Standard Clause 1.
Neighborhoods We Serve in Los Angeles
We design, permit, and build ADUs across Los Angeles, from the hillside neighborhoods to the Valley floor. Crews dispatch from our Los Angeles office, and most sites are reachable within 45 minutes during business hours.
- West Adams
- Highland Park
- Echo Park
- Leimert Park
- Reseda
- Hollywood Hills
Service Area - Cities Near Los Angeles
We serve homeowners throughout the Los Angeles metro, including Culver City, CA, West Hollywood, CA, Beverly Hills, CA, and Pasadena, CA. Each city maintains its own permitting authority, and we produce jurisdiction-specific permit sets rather than recycling Los Angeles drawings.
Serving Los Angeles, CA - Our Local Coverage Area
We’re based in the Los Angeles area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs About ADU in Los Angeles
Standard Plan Program ADUs clear in 2-4 weeks; custom designs take 8-16 weeks depending on plan check backlog. We pre-screen every lot for Standard Plan eligibility before quoting.
California law prohibits HOAs from outright banning ADUs, but design guidelines and architectural review requirements still apply. We review your CC&Rs during the estimate phase.
Yes, permit application and plan check are included in our single contract. We handle LADBS submittal, corrections, and inspection scheduling. Call (424) 407-8266 to start your free estimate.
What happens when you call
- 1A real person answersNo phone trees - talk to a local adu pro.
- 2You get an upfront price rangeHonest numbers before anyone is dispatched. No surprises.
- 3We come out and measureLicensed & insured, at a time that suits you - the visit and the quote are both free.
- 4You get the price in writingLine-itemed, yours to keep, and nothing starts until you say go.
What Los Angeles Customers Say
"The permit set and the build were one contract with one number. Our neighbours used two firms and spent a year watching them blame each other."
- Helena V."Every allowance was itemised at the start, so the finish selections did not turn into a surprise at the end."
- Benedict H."Garage conversion finished on the drawings and close to the schedule. They were honest that the sewer connection was the unknown, and it was."
- Arjun D.