Fast, Reliable ADU Design & Permitting Across Los Angeles
ADU design and permitting on Los Angeles County acreage runs $8,500-$22,000 for the full design and permit set before construction begins, with county-permitted projects typically adding 4-8 weeks to city timelines due to septic, well, and grading requirements. Ellery ADU Studio’s ADU Design & Permitting team coordinates every step from site assessment through final inspection, with dispatch and scheduling run from our Los Angeles office and crews serving unincorporated county lots from Sylmar to the Antelope Valley.
We don’t quote city timelines for county jobs. The LADBS Standard Plan Program - that 6-8 week shortcut every city contractor advertises - stops at the city limit. Cross into LA County Public Works jurisdiction and you’re looking at a different permit track, different setback rules, and often a percolation test that can reshape where the ADU sits on the lot. We’ve priced and permitted over 900 ADUs since 2015, and the county acreage jobs are a distinct category we scope separately from the start.
Call (424) 551-7706 to schedule your free estimate. Written price before any work starts, per Haven Standard Clause 1.
Why Ellery ADU Studio Los Angeles Is Los Angeles’s Preferred ADU Design & Permitting Company
Our reputation in Los Angeles rests on documentation, not slogans. Every client receives a written price before work starts, a documented photo record on every site visit, and the 365-Day Done Right Promise in writing - if the finished ADU doesn’t match the permitted drawings, we make it right. This is Haven Standard governance, not marketing language.
Los Angeles homeowners specifically mention our permit-set thoroughness in reviews. They describe receiving a complete LADBS or LA County Public Works submittal package with structural calcs, Title 24 energy compliance, and drainage plans already coordinated - not a drawing set that stalls at plan check. Our response time to Los Angeles metro and county acreage inquiries is same-day during business hours; a live person answers calls 24/7, no voicemail queue.
Local knowledge matters because Los Angeles contains multiple permitting authorities with incompatible rules. LADBS covers the incorporated city. LA County Public Works covers unincorporated acreage. Pasadena, Long Beach, and Burbank each run their own separate processes. We know which authority governs your parcel before we quote, and we price accordingly.
Our ADU Design & Permitting Services in Los Angeles

Site Assessment
A county acreage site assessment in Los Angeles runs deeper than a city lot walkthrough. We verify jurisdiction - LADBS versus LA County Public Works - then map septic tank location, leach field area, well head and setback radius, slope percentage for grading trigger, and VHFHSZ status. On a two-acre parcel off Little Tujunga Canyon Road in Sylmar, our crew scoped a detached 900-square-foot ADU where the well sat 90 feet from the proposed footprint and the County percolation test drove a larger leach field than the client expected; we pulled a County grading permit for the pad and hauled every load of James Hardie cladding and rebar up a 400-foot unpaved driveway because a 40-foot delivery truck could not turn around. The VHFHSZ designation forced Class A roofing, ember-resistant vents, and ignition-resistant siding into the design before we could even submit - all of which we priced in the scope, not after. Site assessment for county acreage: $1,800-$3,200.

ADU Design & Blueprints
Our architectural team produces permit-ready drawings calibrated to your jurisdiction’s exact submittal requirements. For county acreage, this means grading and drainage plans integrated with the structural set, septic field accommodation in the site plan, and VHFHSZ-compliant material specifications written into the construction notes. We specify and coordinate prefab and modular systems from Abodu, Cover, and Dvele when the project suits factory-built delivery - though on steep county lots with restricted equipment access, stick-built often wins on logistics. Design and blueprint production for county ADUs: $5,500-$14,000 depending on square footage, structural complexity, and whether grading plans are triggered.

Permit Application
LA County Public Works permit application for an ADU requires a complete package: structural plans, Title 24 energy calculations, grading plans if slope exceeds county thresholds, septic clearance from LA County Environmental Health, and well setback verification. We do not submit incomplete packages that stall in plan check. Our permit application service includes all agency coordination, response to corrections, and resubmittal - priced as a line item, not an open-ended hourly. County permit application and coordination: $1,200-$4,800.

HOA & Zoning Compliance
County acreage rarely involves HOAs, but zoning compliance still bites. Minimum lot size for ADUs, maximum coverage ratios, and hillside development restrictions vary by county zone classification. We pull the zoning verification before design starts, not after the client has fallen in love with a footprint that won’t fly. This is included in our site assessment scope.

What happens when you call
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A real person answersNo phone trees - you reach a local pro.
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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 Los Angeles
Ellery ADU Studio specifies and coordinates prefab and modular systems from Abodu, Cover, Dvele, Mighty Buildings, Boxabl, Plant Prefab, Tuff Shed, and James Hardie within our single-contract design-build model. For Los Angeles County acreage with restricted equipment access - narrow gates, steep drives, or unpaved roads like that Little Tujunga Canyon parcel - we evaluate whether a factory-built module can actually reach the pad or whether site-built with James Hardie cladding and conventional framing makes more logistical sense. We don’t sell a brand; we specify what works for your access, your slope, and your county permit conditions. All material lead times are priced into the written scope before signing.
Common ADU Design & Permitting Problems We See in Los Angeles Homes

- Scoping a county lot on the LADBS Standard Plan timeline. Pre-approved plans and 6-8 week plan check do not cross into County jurisdiction. Contractors who promise this shortcut for a county parcel either don’t know the boundary or don’t care - either way, the schedule promise collapses at submittal.
- Treating septic and well setbacks as a post-design detail. We’ve redrawn entire footprints after discovering the leach field expansion radius or well setback forces the ADU 20 feet left of where the client wanted it. We test for this in site assessment, before ink hits blueprint.
- Ignoring VHFHSZ triggers on hillside acreage. Class A roofing assemblies, ember-resistant vents, and ignition-resistant cladding add material lead time and cost that flatland quotes omit. We flag this in the first site walk, price it in the scope, and specify the materials in the permit set.
- Undersizing equipment access in the construction budget. A 40-foot module delivery truck can’t turn around on a 400-foot unpaved driveway. We photograph the access route, measure turning radius, and price crane or smaller-vehicle alternatives before the client commits.
Pricing for ADU Design & Permitting in Los Angeles, CA
ADU design and permitting on Los Angeles County acreage typically runs $8,500-$22,000 for the complete package from site assessment through issued permit. The spread depends on four factors we verify before quoting: jurisdiction (County adds grading and septic coordination), square footage (larger ADUs need more structural and energy calc detail), slope (grading plans trigger at county thresholds and add engineering cost), and VHFHSZ status (fire-resistant material specifications add design time and material specification work).
Here’s how it breaks:
- Site Assessment (jurisdiction, septic, well, slope, VHFHSZ): $1,800-$3,200
- ADU Design & Blueprints (architectural, structural, Title 24): $5,500-$14,000
- Permit Application & Agency Coordination: $1,200-$4,800
Every project is quoted with a written price before any work begins, per Haven Standard Clause 1. No “call for pricing.” No range that widens after you sign. The number you receive is the number on the contract. Call (424) 551-7706 for your exact quote - estimates are free, and we offer a Free Second Opinion on any written estimate already in hand.
We Also Serve Cities Near Los Angeles

Ellery ADU Studio’s Los Angeles office dispatches crews throughout the metro, including South Gate, Inglewood, Compton, and Hawthorne. Each of these incorporated cities runs its own permit process distinct from both LADBS and LA County Public Works - we verify jurisdiction and price accordingly, never assuming one city’s timeline applies to another.
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 - ADU Design & Permitting in Los Angeles

No. The LADBS Standard Plan Program is exclusive to the incorporated City of Los Angeles. Unincorporated LA County acreage falls under LA County Public Works, which has no equivalent pre-approved plan library. County ADUs go through full plan check, typically 3-4 months versus the 6-8 weeks LADBS advertises for Standard Plan projects. Call (424) 551-7706 and we’ll verify your parcel’s jurisdiction before quoting - estimates are free.
They can relocate the entire footprint. LA County Environmental Health requires minimum separation distances between septic leach fields, well heads, and any new structure foundation. On one Sylmar parcel, our percolation test results expanded the required leach field area and pushed the ADU 20 feet from its original siting. We discover this in site assessment, before design, and price the revised footprint in the written scope. Call (424) 551-7706 for an exact quote on your lot - estimates are free.
City lots are flat and paved; county acreage is often sloped, unpaved, and sheds water across the pad. LA County Public Works requires grading and drainage plans on slopes that trigger their threshold, with engineered cut-fill balances and drainage retention designed to prevent downstream erosion. Flatland city jobs rarely trigger this. We survey slope percentage in our site assessment and include grading engineering in the permit set when required. Call (424) 551-7706 to schedule your site assessment - estimates are free.
Restricted access adds material handling cost that flatland jobs don’t carry. Narrow gates, steep grades, or unpaved roads can block standard delivery trucks and require smaller vehicles, cranes, or hand-carry of materials. On the Little Tujunga Canyon project, we hauled every load of James Hardie cladding and rebar up a 400-foot driveway because a 40-foot truck couldn’t turn around. We photograph and measure access during site assessment, then price the logistics line item in your written quote. Call (424) 551-7706 for your exact logistics assessment - estimates are free.
It mandates Class A roofing assemblies, ember-resistant vents, and ignition-resistant exterior cladding - materials with longer lead times and higher cost than standard assemblies. Bel Air, Brentwood, Sylmar, Sun Valley, and any lot bordering the Santa Monica Mountains fall under this designation. We verify VHFHSZ status in our first site assessment, specify compliant materials in the permit set, and price the upgrade in the written scope before you sign. Call (424) 551-7706 to check your parcel’s fire zone status - estimates are free.
Ready to price your Los Angeles County acreage ADU? Call (424) 551-7706 to schedule your free estimate. Written price before any work starts. Documented photo record on every visit. 365-Day Done Right Promise, in writing, before the project begins.
Written by Nadia Ellery, Owner at Ellery ADU Studio, serving Los Angeles since 2015.