ADU in Los Angeles, CA
A Junior ADU & Interior Conversion in Los Angeles typically runs $80,000-$180,000 all-in, while ADU Site Prep & Utilities add $15,000-$75,000 depending on hillside conditions, electrical service size, and whether the lot sits in a Very High Fire Hazard Severity Zone. We’re Ellery ADU Studio, and we’ve handled Junior ADU & Interior Conversion and ADU Site Prep & Utilities as part of our single-contract design-build work since 2015. Call (424) 551-7706 for a written price before any work starts.
Why Los Angeles Homes Are Different
Los Angeles is built on a grid of 50×150-foot lots carved out in the 1920s-1950s, with detached single-car garages at the rear property line, alley-accessed. That physical pattern makes garage conversion the default ADU type here in a way it isn’t in neighboring cities. The LADBS Standard Plan Program, unique to the City of Los Angeles, offers pre-approved architectural plans that skip plan check entirely, compressing permitting from 3-6 months to 6-8 weeks. Contractors who don’t know this program routinely quote full timelines and lose bids.
The San Fernando Valley adds a different profile: 1950s-1960s ranch tracts on wider lots where new detached construction dominates. Hillside neighborhoods from Bel Air to Sylmar fall inside Very High Fire Hazard Severity Zones, mandating Class A roofing, ember-resistant vents, and ignition-resistant cladding that flatland zones don’t require. LA’s dry Mediterranean climate removes weather delays, but fire-zone material lead times don’t.
Our Main Los Angeles Services
Los Angeles homeowners reach out most often for these three project types, each with its own Los Angeles-specific permitting path and cost structure.
ADU Design & Permitting in Los Angeles
We produce the permit set as the core product, not an afterthought. In Los Angeles, that means navigating the LADBS Standard Plan Program when it fits, or producing a custom Title 24 energy calculation and structural package when it doesn’t. Every permit set we deliver is backed by our 365-Day Done Right Promise. ADU Design & Permitting in Los Angeles.
Garage Conversion ADU in Los Angeles
The city’s alley-accessed 1920s-1950s garages are the ideal conversion candidate: by-right under state law, often with existing concrete slabs that need only moisture-barrier and finish work. We assess slab thickness, roof structure, and utility routing before quoting. Garage Conversion ADU in Los Angeles.
New Detached ADU in Los Angeles
On wider Valley lots or where the existing garage is structurally unsound, new detached construction is the better path. We coordinate prefab systems from Abodu or Cover within the same single contract, handling foundation, utility trenching, and final inspection. 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 solves the problem of homeowners who want rental income or multigenerational housing but lack the rear-lot space or alley access that makes garage conversion possible. In Highland Park, Koreatown, and Leimert Park, we regularly convert interior space - basements, above-garage rooms, or existing bedrooms - into code-compliant JADUs with separate entrances and kitchenettes, working within the original footprint to avoid triggering full ADU setback rules. Junior ADU & Interior Conversion is often the only by-right option on hillside lots in Bel Air or Brentwood where flat buildable area is scarce.
Basement ADU
Signs you need it
Your 1920s-1950s Los Angeles home has a below-grade basement with 7.5+ foot ceiling height, exterior access, and no current habitability due to moisture or egress issues.
What it costs in Los Angeles
Basement ADU conversions in Los Angeles typically run $85,000-$165,000 all-in, including moisture mitigation, egress window installation, and full MEP rough-in.
How we do it
We test for radon and moisture intrusion, install perimeter drainage and sump systems if needed, cut egress windows to LADBS specifications, then frame, insulate, and finish with documented photo records at each phase.
Room-to-ADU Conversion
Signs you need it
You have a 200+ square foot ground-floor room with direct exterior access and want to add a kitchenette and separate meter for rental income.
What it costs in Los Angeles
Room-to-ADU conversions in Los Angeles typically run $75,000-$140,000, depending on whether the electrical panel accepts a sub-meter and if plumbing rough-in exists.
How we do it
We verify existing structure against Type V-B construction requirements, design the kitchenette layout for code minimum clearances, run dedicated electrical and plumbing, and produce the JADU compliance certificate for LADBS.
What Junior ADU & Interior Conversion Costs in Los Angeles
| Item | Typical range in Los Angeles |
|---|---|
| Basement ADU conversion | $85,000 - $165,000 |
| Room-to-ADU conversion | $75,000 - $140,000 |
| Above-garage ADU conversion | $95,000 - $180,000 |
Can a Junior ADU have its own address in Los Angeles?
Yes, LADBS allows separate mailing addresses for JADUs with independent utility meters, though USPS assignment requires additional coordination. Call (424) 551-7706 and we’ll walk you through what’s needed for your specific lot.
Does converting a room to a JADU trigger a full property reassessment in Los Angeles?
No, under California law JADUs are excluded from separate property tax reassessment; only the improvement value is added to your existing assessment. For exact implications on your parcel, call (424) 551-7706 for a free review.
ADU Site Prep & Utilities in Los Angeles
ADU Site Prep & Utilities in Los Angeles addresses the gap between an approved permit set and a buildable site: hillside grading in fire zones, electrical service upgrades from 100A to 200A panels, and sewer lateral replacements on 1920s clay pipe. In Sylmar and Sun Valley, we’ve replaced collapsed Orangeburg pipe; in Koreatown, we’ve upgraded panels in 1950s bungalows where the original 60A service can’t handle a second dwelling unit. ADU Site Prep & Utilities is where design-build coordination matters most, because the electrician and the grader can’t point at each other when both work for us.
Foundation & Grading
Signs you need it
Your hillside lot in Bel Air, Brentwood, or Sylmar shows visible slope creep, or your existing garage slab is cracked, un-reinforced, or under 4 inches thick.
What it costs in Los Angeles
Foundation and grading work in Los Angeles typically runs $18,000-$55,000, with hillside anchor systems and retaining walls at the higher end.
How we do it
We perform geotechnical testing, design spread footings or pier systems per LADBS hillside requirements, rough grade to drainage plans, and compact to 95% standard Proctor before the slab pour.
Electrical Panel Upgrade
Signs you need it
Your existing panel is rated under 200 amps, has no open breaker slots, or still uses Zinsco or Federal Pacific breakers that LADBS will flag on inspection.
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 grounding system.
How we do it
We size the new load calculation per NEC Article 220, coordinate LADWP service lateral capacity, pull the LADBS permit, and schedule inspection before rough-in begins.
What ADU Site Prep & Utilities Costs in Los Angeles
| Item | Typical range in Los Angeles |
|---|---|
| Foundation & grading | $18,000 - $55,000 |
| Electrical panel upgrade | $4,500 - $12,000 |
| Plumbing lateral replacement | $8,000 - $22,000 |
Does LADWP require a separate service lateral for an ADU in Los Angeles?
Not always; many ADUs share the existing lateral if capacity allows, but LADWP requires a load letter and may mandate upgrade. We handle LADWP coordination as part of our single contract. Call (424) 551-7706 to check your service size.
How long does hillside grading approval take in Los Angeles?
LADBS hillside grading permits add 4-8 weeks beyond standard plan check, longer if geotechnical reports require peer review. We submit complete packages to avoid cycle delays. Call (424) 551-7706 for a timeline on your specific slope.
Brands We Service in Los Angeles
We specify and coordinate prefab and modular systems from Abodu, Cover, Dvele, and Mighty Buildings within the same single contract, with parts and warranty documentation stocked locally for turnaround without manufacturer delay. See our brands for full specifications.
Pricing for ADU in Los Angeles, CA
| Service | Typical range in Los Angeles |
|---|---|
| Junior ADU & Interior Conversion - Basement ADU | $85,000 - $165,000 |
| Junior ADU & Interior Conversion - Room-to-ADU | $75,000 - $140,000 |
| Junior ADU & Interior Conversion - Above-Garage ADU | $95,000 - $180,000 |
| ADU Site Prep & Utilities - Foundation & Grading | $18,000 - $55,000 |
| ADU Site Prep & Utilities - Electrical Panel Upgrade | $4,500 - $12,000 |
| ADU Site Prep & Utilities - Plumbing Lateral | $8,000 - $22,000 |
In Los Angeles, hillside fire-zone requirements, LADWP service upgrades, and 1920s-era utility infrastructure push prices toward the higher end of each range. Under Haven Standard Clause 1, every project receives a written price before any work starts; no call-for-pricing, no scope creep.
Neighborhoods We Serve in Los Angeles
Our Los Angeles office dispatches crews across the city basin and valley, with scheduling coordinated locally. Typical response for initial site assessment is within 48 hours.
- Highland Park
- Koreatown
- Leimert Park
- Bel Air
- Sylmar
Service Area - Cities Near Los Angeles
We serve homeowners throughout the Los Angeles metro, with active projects and permit coordination in South Gate, CA, Inglewood, CA, Compton, CA, and Hawthorne, CA. Each city maintains its own permitting authority distinct from LADBS, and we produce jurisdiction-specific permit sets accordingly.
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
Through the LADBS Standard Plan Program, permitting compresses to 6-8 weeks versus 3-6 months for custom plans; we route projects through this program whenever the lot and design qualify. Call (424) 551-7706 to check your eligibility.
California law prohibits HOAs from outright banning ADUs, but some Los Angeles condo associations and planned developments impose design guidelines or parking requirements that add cost; we review CC&Rs during our initial site assessment.
Yes, if your lot sits in a Very High Fire Hazard Severity Zone, Class A roofing, ember-resistant vents, and ignition-resistant cladding are mandatory, typically adding $8,000-$20,000 to exterior finishes; we identify zone status before quoting.
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
"Detached unit in the back garden. Good design, good build quality, and the cost changes were documented and agreed in advance."
- Stefan B."The rental income has covered the payment since the second month. They were realistic about the numbers rather than optimistic."
- Odette N."They walked us through setbacks and utility capacity before we paid anything, and told us one of our two options was not going to get approved."
- Mireille T.