ADU in Los Angeles, CA
Junior ADU & Interior Conversion in Los Angeles typically runs $85,000-$165,000 all-in for a permitted, move-in-ready unit, while ADU Site Prep & Utilities ranges from $15,000-$75,000 depending on foundation condition and utility distance. We’re Ellery ADU Studio, a design-build practice that handles drawings, permits, and construction under one contract at one written price. Call (213) 698-7591 to schedule your free estimate.
Los Angeles sits at the center of California’s ADU movement, but the real story here is decades of unpermitted granny flats and garage conversions across Van Nuys, Boyle Heights, and Panorama City. Much of our work involves legalizing existing structures through LADBS’s as-built permit pathway, not ground-up builds. That dual-track reality, unfamiliar to contractors from Burbank or Long Beach, shapes every project we take on.
Why Los Angeles Homes Are Different
The 1950s-1970s postwar tract homes blanketing the San Fernando Valley and South LA dominate our project list. Most have detached two-car garages wired with original 60-amp or 100-amp sub-panels that can’t support a converted unit. In Highland Park, Silver Lake, and Mid-City, the 1920s-1940s Craftsman bungalows sit on raised wood foundations, complicating plumbing tie-ins and requiring invasive subfloor work.
LA’s mild climate makes mini-split heat pumps the standard HVAC choice, but fire hazard zones change everything. Hollywood Hills, Topanga, Pacific Palisades, and portions of Eagle Rock fall within CAL FIRE-designated Very High Fire Hazard Severity Zones. ADU construction there triggers WUI ignition-resistant requirements: Class A roofing, ember-resistant vents, and noncombustible siding that can add tens of thousands over an identical flatland project.
Many longtime homeowners built backyard structures informally in the 1980s-2000s. LADBS records are full of these unpermitted additions, and the post-2020 legalization window means we spend as much time reading old aerial photos and negotiating inspector sign-offs on non-code construction as we do framing new walls.
Our Main Los Angeles Services
Los Angeles homeowners call us most often for these three services, each with its own dedicated page:
ADU Design & Permitting in Los Angeles
We produce permit-ready construction documents, structural calculations, and LADBS submission packages as a standalone service or as the first phase of a full build. In Los Angeles, this means navigating both the streamlined ADU ordinance and the as-built legalization pathway for existing structures. Our permit sets include Title 24 energy compliance, green building checklist, and fire-department clearance where required. ADU Design & Permitting in Los Angeles covers the full documentation package.
Garage Conversion ADU in Los Angeles
The most common ADU type in Los Angeles, especially in the Valley and South LA where detached two-car garages are standard. We assess slab thickness, ceiling height, and electrical service before quoting. Most conversions require panel upgrades and often sewer lateral work to separate from the main house. Garage Conversion ADU in Los Angeles details our full process.
New Detached ADU in Los Angeles
Ground-up construction in the backyard, governed by Los Angeles’s 4-foot side and rear setback rules for ADUs under 800 square feet. In fire hazard zones, we specify James Hardie noncombustible siding and Class A roofing from the start. Foundation choice, slab-on-grade versus raised perimeter, depends on slope and soil conditions. New Detached ADU in Los Angeles explains sizing and siting options.
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 a specific problem: homeowners who want rental income or multigenerational housing without building new square footage. The city’s stock of older homes with underutilized basements, large attics, and spare rooms makes this path attractive, especially in neighborhoods where lot coverage already maxes out. We handle Junior ADU & Interior Conversion from as-built documentation through final inspection, including the HCD checklist and utility separation where required.
Room-to-ADU Conversion
Signs you need it
You have a 300-500 square foot spare bedroom or den with a window and want to add a kitchenette and separate entrance for rental income.
What it costs in Los Angeles
Room-to-ADU conversions in Los Angeles typically run $85,000-$140,000 including permits, kitchenette rough-in, and egress window installation.
How we do it
We measure existing conditions, produce an as-built floor plan, design the kitchenette layout to meet Title 24, pull the LADBS permit, and coordinate electrical and plumbing rough-in before finish work.
Interior JADU
Signs you need it
You want to convert part of your existing home into a Junior ADU with its own entrance, sharing utilities with the main house under state JADU rules.
What it costs in Los Angeles
Interior JADU projects in Los Angeles typically range $75,000-$125,000 including the required exterior door, kitchenette, and fire separation upgrades.
How we do it
We verify the owner-occupancy requirement, design for sound transmission control between units, install the separate exterior door, and pull the JADU permit with LADBS.
What Junior ADU & Interior Conversion Costs in Los Angeles
| Item | Typical range in Los Angeles |
|---|---|
| Room-to-ADU conversion (all-in) | $85,000-$140,000 |
| Interior JADU (all-in) | $75,000-$125,000 |
| Above-garage ADU (all-in) | $120,000-$185,000 |
Does a Junior ADU need its own meter in Los Angeles?
No, state law allows JADUs to share electrical and water meters with the primary residence, though we recommend sub-metering for rental situations. Call (213) 698-7591 for an exact quote on your setup.
Can I convert a basement to an ADU in Los Angeles?
Yes if ceiling height clears 7 feet 6 inches and you have legal egress; many LA basements need excavation or window wells to qualify. Call (213) 698-7591 for an exact quote on your basement.
ADU Site Prep & Utilities in Los Angeles
ADU Site Prep & Utilities in Los Angeles addresses the hidden infrastructure that determines whether your project succeeds or stalls at inspection. The city’s aging sewer laterals, undersized electrical panels, and sloped lots in the hills mean site work often costs more than the structure itself. We handle ADU Site Prep & Utilities as a standalone contract or bundled with design-build, with every line item priced in writing before breaking ground.
Electrical Panel Upgrade
Signs you need it
Your existing panel is 100 amps or less, or the main breaker trips when you run the dryer and air conditioner together.
What it costs in Los Angeles
Electrical panel upgrades in Los Angeles typically run $4,500-$9,000 including LADBS permit, SCE coordination, and new grounding.
How we do it
We verify SCE service capacity, specify the new panel and load calculation per NEC, pull the permit, coordinate the utility disconnect, and schedule LADBS inspection before ADU rough-in.
Plumbing Lateral
Signs you need it
Your home has original cast iron sewer piping, frequent backups, or the ADU location is more than 30 feet from the main sewer line.
What it costs in Los Angeles
Plumbing lateral replacement or extension in Los Angeles typically costs $8,000-$18,000 including trenching, city sewer connection permit, and video inspection.
How we do it
We video the existing line, locate the city tap, design the routing to avoid established trees, trench or directional-bore as conditions require, and pressure-test before LADBS and Bureau of Sanitation sign-off.
What ADU Site Prep & Utilities Costs in Los Angeles
| Item | Typical range in Los Angeles |
|---|---|
| Electrical panel upgrade | $4,500-$9,000 |
| Plumbing lateral replacement/extension | $8,000-$18,000 |
| Foundation and grading (new detached) | $15,000-$35,000 |
Does Los Angeles require sewer lateral replacement for ADUs?
Not automatically, but LADBS requires a sewer capacity letter if the line is original cast iron or shows failure on video; many older homes need partial replacement. Call (213) 698-7591 for an exact quote after inspection.
How long does utility coordination take in Los Angeles?
SCE electrical service upgrades typically take 6-10 weeks from application to meter release; we submit concurrently with LADBS permits to keep the schedule tight. Call (213) 698-7591 to plan your timeline.
Brands We Service in Los Angeles
We specify and coordinate prefab and modular systems from Plant Prefab, Tuff Shed, and James Hardie within our single-contract design-build model. Our Los Angeles office stocks common James Hardie trim and siding for fire-zone projects, with most specialty orders arriving in 5-7 business days. See our brands for the full list.
Pricing for ADU in Los Angeles, CA
| Service | Typical range in Los Angeles |
|---|---|
| Room-to-ADU conversion | $85,000-$140,000 |
| Interior JADU | $75,000-$125,000 |
| Above-garage ADU | $120,000-$185,000 |
| Electrical panel upgrade | $4,500-$9,000 |
| Plumbing lateral replacement/extension | $8,000-$18,000 |
| Foundation and grading (new detached) | $15,000-$35,000 |
| Gas line extension | $3,500-$8,000 |
| Landscaping and hardscape restoration | $5,000-$15,000 |
Fire hazard zone requirements, hillside grading, and as-built legalization complexity push Los Angeles prices above flatland, ground-up projects. Every figure above is guaranteed in writing before work starts, per Haven Standard Clause 1; no change orders, no door-side upsells.
Neighborhoods We Serve in Los Angeles
We work across Los Angeles from our local office, with crews dispatched daily to projects in progress. Response time for new estimates is typically 48-72 hours from your call.
- Van Nuys
- Boyle Heights
- Panorama City
- Highland Park
- Silver Lake
Service Area - Cities Near Los Angeles
Our crews serve homeowners throughout the Los Angeles metro, including South Gate, CA, Gardena, CA, Inglewood, CA, and Compton, CA. Each city has its own permit pathway and inspection schedule; we coordinate directly with the local building department rather than applying Los Angeles assumptions elsewhere.
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
Streamlined ADU permits under state law should process within 60 days; as-built legalization applications often take 90-120 days due to additional plan check rounds. We track every submittal and flag delays directly with the plan check engineer.
Yes, but CAL FIRE WUI requirements apply: Class A roofing, ember-resistant vents, and noncombustible siding such as James Hardie. These add material cost but do not block permitting if met.
We pull every permit as part of our single-contract scope; LADBS, SCE, and Bureau of Sanitation coordination is our responsibility, not yours. You receive copies of all approved permits and inspection sign-offs in your project binder.
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
"Handled the whole planning process. We went to one hearing and that was it."
- Rowena C."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.