Fast, Reliable New Detached ADU Across East Los Angeles
A new detached ADU in East Los Angeles typically costs between $265,000 and $410,000 all-in, from the first County filing through final inspection, depending on site conditions, grading, and how far your utility runs have to travel. That number assumes the drawings, the permit set, and the construction are under one contract, at one written price, set before we touch the lot. We’re Ellery ADU Studio, and we’ve designed, permitted, and built more than 900 ADUs since 2015, every one of them quoted in writing before work began. If you’re weighing a backyard unit on a subdivided East LA lot, call (971) 497-2402 and we’ll scope it for your specific parcel, not a generic template.

East Los Angeles is not the City of Los Angeles. It’s unincorporated LA County, and the permitting path for a new detached ADU here runs through LA County Department of Regional Planning and LA County Building & Safety. That single fact changes the fee structure, the setbacks, the septic and well clearances, and the legalization options for older backyard casitas. Our New Detached ADU team works that County pathway week after week, so the quote you get reflects what this parcel actually requires, not what a City of LA checklist would assume.
Why Ellery ADU Studio Is East Los Angeles’s Preferred New Detached ADU Company
Most East Los Angeles homeowners come to us after a quote from a City of LA contractor falls apart at the County counter. They were told a detached ADU would clear planning in six weeks, then discovered their lot needs a septic setback variance and a soils report for the existing slab. We don’t quote that way. We walk the parcel, pull the County records, check the panel, and only then put a number in writing. That’s Haven Standard Clause 1, and it’s why we put the price on the page instead of asking you to call for one.
Backyard ADU projects here are not anonymous. On a flag lot off Mednik Avenue in the Belvedere district, we scoped a 749-square-foot detached unit with a 60-foot grading run for drainage and a 12-foot rear setback from the septic leach field. The existing main panel was tapped out, so our crew routed a new sub-panel 85 feet from the main service and spec’d a 36,000 BTU Mitsubishi mini-split because East LA hits 105°F on Santa Ana days and an unconditioned unit is unrentable by August. The job went from quote to County approval in nine weeks.
Nadia Ellery founded this studio in 2015, the year California’s ADU permitting landscape actually shifted, and she structured the company so the permit set is the core product, not an afterthought. One contract covers design, permitting, and construction, so neither the designer nor the builder can point at the other when something is off. Our license number appears on every page. Background-checked crews, a documented photo record on every visit, and a live person answering calls 24/7.
Our New Detached ADU Services in East Los Angeles

Custom Built ADU
A custom-built detached ADU in East Los Angeles gives you full control over the footprint, the roofline, and how the unit relates to the alley, the main house, and the neighbors. On the tight 1920s-to-1950s lots that dominate East LA, that control matters because a standard plan often doesn’t clear the County’s rear and side setbacks without a variance. We draw to your parcel’s actual dimensions, then build to those drawings under a single written price. Custom builds here typically run $320,000 to $460,000 depending on size, finishes, and site work.

Studio ADU
Studio ADUs are the most common request we see in East Los Angeles: a single open room with a kitchenette and full bath, often 400 to 550 square feet, placed where the old detached garage used to stand. Because East LA lots are so tightly subdivided, the studio footprint is frequently the only one that fits without triggering a setback variance or eating the whole backyard. Expect $245,000 to $330,000 for a studio with a mini-split, a proper sub-panel, and County-approved drainage.

1-Bed & 2-Bed ADU
For East Los Angeles homeowners who want a long-term rental asset, a one-bedroom unit with a separate bedroom and a real door between spaces rents materially better than a studio, and a two-bedroom unit rents better still. These start around $295,000 and can reach $500,000 on the upper end once you factor in upgraded finishes and a larger footprint. On a narrow East LA lot, the two-bedroom often requires a two-story design, which changes the structural scope. We’ll show you the price difference in the written quote, line by line.

Prefab ADU Installation
Prefab and modular systems can work in East Los Angeles, but only when the existing site is prepared for them. We specify and coordinate Abodu, Cover, Dvele, and Mighty Buildings units within the same single contract. The catch on East LA lots is access: a prefab module needs a crane or a wide-load truck, and many of the rear-alley lots here can’t take either without a neighbor’s driveway easement or a street closure. We scope that before you commit to a system. Prefab installs including site work typically run $270,000 to $390,000.

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.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in East Los Angeles
We specify and coordinate prefab and modular systems from Abodu, Cover, Dvele, and Mighty Buildings, and we’ve built with James Hardie siding on dozens of East Los Angeles projects. Because we’re the single contract on the job, the brand choice doesn’t become a finger-pointing exercise between a module maker and a site contractor. We handle the County submittals, the foundation, the utility connections, and the final inspection regardless of which system you choose. One written price covers all of it.

Common New Detached ADU Problems We See in East Los Angeles Homes

- Assuming City of LA ADU rules apply. East Los Angeles is unincorporated LA County. A placement that clears City of LA setbacks may fail County septic setback and well clearance requirements on day one. We check the County’s rules before we draw anything.
- Long material hauls and alley access failures. The subdivided 1920s-to-1950s lots here often have narrow rear alleys that a concrete truck or a prefab module carrier simply can’t navigate. If that’s your parcel, the price needs to include a pump truck, a crane reroute, or a staged delivery. We scope it up front, not when the truck is stuck on the corner of Hammel Street.
- Building on an informal casita slab without a County soils report. A lot of East LA backyards have an old unpermitted casita sitting on a slab that was poured decades ago, maybe without rebar, maybe without proper grading. Building a new unit on that slab without a soils report is how you get a failed foundation and a full re-pour. We audit the slab before we quote.
- No mechanical cooling on an inland basin lot. East LA sits well inland and regularly hits 95°F to 105°F during summer heat events. A detached unit without a mini-split is not rentable from June through September. This is not an upgrade. It’s table stakes for an East Los Angeles ADU.
Pricing for New Detached ADU in East Los Angeles, CA
Here are the numbers as we see them on East LA parcels in 2026.
| ADU Type | Typical East Los Angeles Range |
|---|---|
| Studio ADU (400-550 sq ft) | $245,000 - $330,000 |
| 1-Bed ADU (500-750 sq ft) | $295,000 - $410,000 |
| 2-Bed ADU (750-1,000 sq ft) | $380,000 - $500,000 |
| Custom Built ADU (site-specific) | $320,000 - $460,000 |
| Prefab ADU Installation (including site work) | $270,000 - $390,000 |
What moves the number on an East Los Angeles lot: grading runs for drainage, septic and well setback variances, how far the new sub-panel has to travel from the main service, alley access for equipment, and whether you’re building fresh or legalizing an existing casita. Every quote we write is a fixed price, set before any work starts, under Haven Standard Clause 1. The scope is locked at signing. No door-side upsells, no change orders for things we should have caught in the first walk. Call (971) 497-2402 to schedule a free estimate on your specific parcel. If you already have a written estimate from another company, bring it in. We’ll give you a free second opinion.
We Also Serve Cities Near East Los Angeles

Our New Detached ADU in East Los Angeles work extends across the wider LA Basin and the state, including Los Angeles, San Diego, San Jose, and San Francisco. Dispatch and scheduling are coordinated from our Los Angeles office; crews serve East Los Angeles locally. If your property sits near the County line or in a neighboring jurisdiction, call us and we’ll confirm which permitting path your parcel falls under before you commit to anything.
Serving East Los Angeles, CA - Our Local Coverage Area
We’re based in the East 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 - New Detached ADU in East Los Angeles

East Los Angeles is unincorporated LA County, so every new detached ADU permit runs through LA County Department of Regional Planning and LA County Building and Safety, not the City of LA. This changes the fee schedule, the ordinance language, the septic and well setbacks, and the review timeline. A City of LA contractor who doesn’t file County paperwork regularly will likely misquote the project. Call (971) 497-2402 for an exact scope on your parcel, estimates are free.
On an East Los Angeles lot served by septic, the County requires a defined setback between your new ADU’s foundation and the leach field, and between the unit and any well. Those clearances can kill a standard backyard placement on day one, especially on the tightly subdivided 1920s-to-1950s parcels common here. We check the County’s setback requirements before we draw the footprint. Call (971) 497-2402 and we’ll pull the records for your lot.
Legalizing an existing casita in East Los Angeles typically runs $120,000 to $220,000 when the structure is sound, including the County’s legalization application, electrical and plumbing corrections to bring the unit to code, and a new sub-panel where the old informal wiring tapped the main panel. Building a new detached ADU on the same lot typically runs $245,000 to $500,000. A pre-construction electrical and plumbing audit comes first because the informal systems we see are often unsafe. Call (971) 497-2402 for a written price on legalizing your specific casita.
Yes, practically speaking. East LA sits inland in the LA Basin and routinely hits 95°F to 105°F during summer heat events and Santa Ana wind conditions, far hotter than coastal Los Angeles neighborhoods. A detached unit without a mini-split becomes uninhabitable by midday in July. We include mechanical cooling as a baseline line item in every East Los Angeles ADU quote. Call (971) 497-2402 for a written quote that includes it.
On East Los Angeles lots with narrow rear alleys, getting a concrete truck, crane, or prefab module carrier to the build site may require a pump truck, a neighbor’s driveway easement, or a city street closure permit. Those costs are real and they’re line items in our quotes. We’re the only ones paid to scope the access problem before you sign. Call (971) 497-2402 and we’ll assess your alley access as part of the free estimate.
Call (971) 497-2402 to schedule your free written estimate for a new detached ADU in East Los Angeles. If you have a written estimate from another company, bring it in for a free second opinion at no charge.
Written by Nadia Ellery, Owner at Ellery ADU Studio, serving East Los Angeles since 2015.