Fast, Reliable ADU Design & Permitting Across Westlake Village
ADU design and permitting in Westlake Village typically runs $8,500-$18,000 for the full service, from site assessment through issued permit, with most projects reaching plan-check submittal within 4-6 weeks of contract signing. Because Westlake Village straddles the Los Angeles County and Ventura County border, the exact jurisdiction, fee schedule, and timeline depend on which of three agencies actually reviews your parcel. Our ADU Design & Permitting team verifies this before any design work begins.
We coordinate dispatch and scheduling from our Los Angeles office, and crews serve Westlake Village properties directly. If you’re on a Three Springs cul-de-sac, along Westlake Boulevard, or tucked into the North Ranch area, we map your parcel to the correct authority first. Call (805) 301-9518 to schedule your free estimate. Every project receives a written price before work starts, per Haven Standard Clause 1.
Why Ellery ADU Studio Camarillo Is Westlake Village’s Preferred ADU Design & Permitting Company
We’ve designed, permitted, and built ADUs across Westlake Village since 2015, the year California’s ADU laws shifted. That timing matters. We learned the local landscape as it formed, not after the fact. Our 900+ completed ADUs include dozens in Westlake Village proper and the surrounding master-planned neighborhoods, each with a documented photo record and a written price locked at signing.
Clients in Westlake Village choose us because we handle the jurisdiction puzzle that defeats most contractors. We verify county parcel maps. We know which side of Westlake Boulevard tips into Ventura County, which cul-de-sacs fall under Thousand Oaks, and where the City of Westlake Village’s Building & Safety department holds sway. This isn’t trivia. Pulling a permit through the wrong agency costs weeks and sometimes restarts the entire process.
Our response time to Westlake Village inquiries is same-day during business hours, and a live person answers calls 24/7. Nadia Ellery, who leads our studio, reviews every Westlake Village site assessment personally before the design phase begins. We don’t hand off your project to a rotating cast.
Our ADU Design & Permitting Services in Westlake Village

Site Assessment
Every Westlake Village project starts with a site assessment that includes jurisdiction verification. We pull the county parcel map, confirm whether your address routes to the City of Westlake Village, Ventura County Planning Division, or Thousand Oaks Community Development, and document existing conditions with a photo record you receive. On a recent Three Springs-area assessment, we mapped two adjacent parcels on the same cul-de-sac: one in the City of Westlake Village, one in unincorporated Ventura County. The City parcel sat in a Very High Fire Hazard Severity Zone. The Ventura County parcel did not. That single finding changed material specifications, setback calculations, and the submittal timeline for each. We build this verification into every Westlake Village site assessment, because guessing wrong here cascodes through everything that follows.

ADU Design & Blueprints
Our permit sets are the core product, not an afterthought. For Westlake Village properties, we design to the specific authority’s setback, height, and lot-coverage rules from the first draft. The City of Westlake Village allows detached ADUs up to 1,200 square feet on most residential lots, but Ventura County’s unincorporated areas may apply different lot-coverage formulas. Thousand Oaks enforces its own rear-setback minimums. We don’t design to a generic standard and hope for a variance. We design to your parcel’s actual rules. For properties in the VHFHSZ, we specify ignition-resistant construction from the start: ember-resistant vents, Class A roofing, fire-rated siding, typically James Hardie or equivalent. This avoids the plan-check correction that restarts your review clock.

Permit Application
We file the complete submittal packet, not you. For Westlake Village addresses, this means routing to the correct agency with the correct fee schedule already calculated. The City of Westlake Village’s Building & Safety department, Ventura County Planning Division, and Thousand Oaks Community Development each charge different plan-check fees and operate on different review timelines. We stagger submittals when a property has multiple structures or when adjacent parcels under common ownership can share utility connections. On that Three Springs project, we submitted the Ventura County permit first, knowing its plan-check timeline was shorter, so framing could begin while the City permit cycled through review. No half-finished shell sat waiting on a committee.

HOA & Zoning Compliance
Nearly every Westlake Village property carries HOA CC&Rs from the original 1960s-1990s master plan. California AB 670 bars HOAs from outright ADU bans, but CC&Rs can impose design and material standards that significantly affect scope and cost. We review your HOA’s architectural guidelines before design finalization, submit the packet to the architectural review committee ourselves, and schedule construction around that approval. Ignoring this step means a stalled submittal after you’ve already paid for plans. We’ve seen contractors skip HOA review, assume the ADU will “pass,” and then face a redesign when the committee rejects roof pitch or exterior color. We don’t let that happen. Under Haven Standard Clause 5 (No Surprises), the scope is locked at signing; no redesigns driven by missed steps.

Title 24 Energy Compliance
All California ADUs must meet Title 24 energy standards. For Westlake Village’s climate zone, this affects insulation values, window performance, and HVAC sizing. We model energy compliance during design, not as a last-minute add-on, and include the required documentation in the permit set.

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 Westlake Village
We specify and coordinate prefab and modular systems within our single-contract model, including Abodu, Cover, and James Hardie. For Westlake Village properties in the VHFHSZ, James Hardie’s fire-rated siding meets ignition-resistant construction requirements without the lead time of custom material sourcing. Abodu and Cover units can be adapted to local setback and height rules during our design phase, not after delivery. We don’t sell you a unit and hand off the permitting. We design, specify, permit, and build as one contract at one written price.
Common ADU Design & Permitting Problems We See in Westlake Village Homes

- Wrong agency, wrong rules. A contractor pulls the permit through Ventura County Planning Division for an address that’s actually in the City of Westlake Village. The setback calculation is wrong. The fee is wrong. The permit gets rejected two weeks in, and the review clock restarts from zero.
- Fire zone materials missed. A designer specifies standard vents and composite roofing for a North Ranch property in the VHFHSZ. Plan check flags it. The correction cycle adds 3-4 weeks and changes the material budget by $4,000-$7,000.
- HOA review ignored. A pool house conversion moves straight to city submittal without architectural review. The HOA committee rejects the exterior color match. The city permit gets held pending redesign. Two months lost.
- Neighboring jurisdiction rules applied. A designer uses Thousand Oaks setback minimums for a Ventura County parcel. The rear yard is 18 inches short. Plan check rejects it. The correction restarts review.
Pricing for ADU Design & Permitting in Westlake Village, CA
A typical ADU design and permitting package in Westlake Village runs $8,500-$18,000 all-in, covering site assessment, full permit set, jurisdiction filing, and HOA architectural review coordination. Garage conversion ADUs, where the existing structure reduces design complexity, typically fall at the lower end, $8,500-$12,500. New detached ADUs in the VHFHSZ, requiring ignition-resistant construction documentation and often structural engineering for hillside lots, run $14,000-$18,000. Junior ADU and interior conversions, where plumbing and electrical routing drive the design, typically range $9,500-$14,000.
What moves the number: jurisdiction (City, County, or Thousand Oaks fees differ), fire zone status, HOA review complexity, and whether the site requires geotechnical or structural engineering. Every project receives a written line-item quote before any work begins, per Haven Standard Clause 1. No change orders on the design and permitting scope. Call (805) 301-9518 for your exact quote. Estimates are free.
We Also Serve Cities Near Westlake Village

Our crews work throughout the western Ventura County and eastern Los Angeles County corridor. We also provide ADU Design & Permitting in Westlake Village and surrounding communities including Thousand Oaks, Agoura Hills, Oak Park, and Calabasas. Each city carries its own jurisdiction rules, and we verify every parcel before design begins.
Serving Westlake Village, CA - Our Local Coverage Area
We’re based in the Westlake Village 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 Westlake Village

It depends on which side of the county line your parcel falls: the City of Westlake Village Building & Safety (LA County), Ventura County Planning Division, or Thousand Oaks Community Development. We verify this with the county parcel map during our site assessment before any design or cost estimate is reliable. Call (805) 301-9518 to schedule your free estimate.
No. California AB 670 prohibits outright ADU bans, but Westlake Village’s master-plan HOAs can impose design, material, and color standards that affect project scope and cost. We submit to your HOA architectural review committee as part of our standard process, before city submittal, to avoid mid-process redesigns. Call (805) 301-9518 for a written quote that includes HOA coordination.
VHFHSZ ADUs require ignition-resistant construction: ember-resistant vents, Class A roofing, and fire-rated siding such as James Hardie. These add material costs that standard-construction ADUs in lower-risk areas don’t carry, typically $4,000-$7,000 on a detached unit. We specify these from the first design draft to avoid plan-check rejection. Call (805) 301-9518 for a project-specific estimate.
We sequence submittals and construction phases around approval timelines. On a recent Three Springs project, we submitted the Ventura County permit first, began framing when it cleared, and ran the City plan check in parallel rather than waiting for sequential approvals. No shell sat idle. This scheduling is built into our project planning, not improvised. Call (805) 301-9518 to discuss timeline for your property.
Yes. Westlake Village’s 1960s-1990s housing stock includes many pool houses and bonus rooms that are natural conversion candidates. We assess structural capacity, utility routing, and fire zone status during site assessment, then design the conversion to meet your specific jurisdiction’s rules. Most conversions run $8,500-$14,000 for design and permitting. Call (805) 301-9518 for a free estimate.
Written by Nadia Ellery, Owner at Ellery ADU Studio, serving Westlake Village since 2015.