Many homeowners underestimate the documentation required to get an ADU permit approved. Then they find out LADBS wants a site plan, floor plans for the existing house, four exterior elevations, a Title 24 energy package, and potentially a structural engineer’s stamp. None of those documents are simple to produce, and most homeowners don’t have any of them on hand. That gap between “I want to build a backyard unit” and “I have a complete, permit-ready plan set the city will accept” is exactly what a professional ADU documentation service is designed to close.

At As-Built Drawings Los Angeles, our principals have been walking LA County homeowners through this process since the late 1990s. The work starts with a field visit to your property and ends with a complete, LADBS-compliant drawing package ready for permit submittal. By the time you finish reading, you’ll know exactly what a documentation service delivers, what’s in the plan set, what it costs, how long it takes, and what to ask before you hire anyone.

What an ADU Documentation Service Actually Does

The phrase “adu documentation service” can sound vague, so it helps to break the work into its two distinct phases: field documentation and CAD production. Both are required. Neither one alone is enough to get a permit approved.

Starting with the Field Visit: Measuring What Already Exists

Before any drawing is drafted, a technician visits your property to capture existing conditions. That means measuring the main house, the proposed ADU footprint or conversion space, the lot boundaries, and any structures that affect setback calculations or lot coverage math. These field measurements are the foundation of everything that follows. LADBS plan checkers are experienced at spotting dimensional inconsistencies, and a site plan that doesn’t match actual property dimensions triggers a correction notice on the first review.

Depending on project complexity and the provider’s workflow, this phase may use traditional manual measurement or 3D laser scanning. Laser scanning can speed up measurement and produce denser datasets than hand measurement alone, which is especially useful on older or irregular buildings where manual methods leave gaps.

From Raw Measurements to a CAD Drawing Package

Once field data is collected, the drafting phase begins. The team converts site measurements into AutoCAD or Revit files that form the backbone of the permit set. This is where a adu documentation service earns most of its value: organizing raw field notes and photos into dimensionally accurate, properly formatted architectural drawings that meet the jurisdiction’s requirements. A full-service provider handles both phases under one roof, which eliminates the handoff errors that occur when measurement and drafting are split between two separate vendors working from different data sets.

The Complete Deliverable List: Your ADU Permit Documentation Checklist

Before you hire any ADU documentation service, ask for their standard deliverable list and compare it to what your jurisdiction actually requires. A permit set that’s missing one sheet delays the entire application. Use this as your baseline ADU permit checklist.

Core Drawings Every ADU Permit Set Needs

A complete ADU plan set for LADBS submittal, or most California city departments, includes three non-negotiable drawing types:

• Site plan showing property lines, setbacks, the existing house footprint, the proposed ADU location, easements, utility routing, and parking
• Floor plans for both the existing structure and the new unit, with room dimensions, door and window locations, and fixture placement
• Exterior elevation drawings showing all four sides of the ADU with labeled height dimensions

Missing or incomplete versions of any of these document types will produce a correction notice on the first plan check.

Supporting Sheets That Depend on Your Project Type

Beyond the core three, the plan set typically includes additional sheets based on whether the project is a new detached structure, a garage conversion, or an attached addition. Common additions include building sections, a roof plan, structural framing sheets with engineering calculations, Title 24 energy compliance documentation (required in California for all new habitable space), and utility connection notes showing how water, sewer, gas, and electrical tie into the main house. On hillside lots or sites with poor soil conditions, LADBS may also require a geotechnical report before the application moves through plan check.

A reliable ADU documentation service will scope all of these items upfront. If a provider quotes you only for a “floor plan and site plan” without asking about your project type or lot conditions, that’s a signal they may not have deep LADBS permitting experience. Ask them directly how they handle scope gaps discovered after work begins.

DADU and JADU Permit Requirements: How Project Type Affects Your Package

Not all ADU projects follow the same documentation path. DADU and JADU permit requirements differ in meaningful ways, and understanding those differences helps you scope the work accurately before you commit to a provider.

A detached ADU (DADU) on a standard lot typically requires the full plan set described above, including structural framing when the unit is new construction. A junior ADU (JADU), which is carved out of existing living space within the primary dwelling, generally requires less structural documentation but still demands a complete set of ADU application forms, a site plan, floor plans showing the conversion area, and Title 24 calculations. Garage conversions fall between these two in complexity: no new foundation is typically required, but the structural adequacy of the existing slab and framing must be addressed in the drawings. Whichever path applies to your project, confirm with your provider that their standard scope covers the specific ADU permit documentation your project type triggers.

How Long the Process Takes from Field Visit to Permit Submission

Timeline surprises are one of the most common homeowner frustrations in the ADU permitting process. Setting accurate expectations from the start lets you plan your contractor schedule, your financing, and your overall project timeline without building in false assumptions.

A Realistic Timeline for Most LA County ADU Projects

From the initial field measurement visit to a complete, submission-ready plan set, most professional services take three to six weeks depending on project complexity and current workload. Once the application is submitted to LADBS or a local city department, the first plan check review typically takes four to eight weeks. Per state ADU law (Government Code Section 65852.2), LADBS must approve or deny a complete ADU application within 60 days, but in practice most projects go through at least one correction cycle, pushing total approval timelines to eight to sixteen weeks or longer. Projects requiring a structural engineer’s stamp or a soils report on a hillside lot consistently sit at the longer end of that range.

What Eats Up Time When Permits Drag On

The single most common reason an ADU permit takes longer than expected is an incomplete initial submittal. A missing sheet, an incorrect setback dimension, or an absent energy compliance form sends the application back and restarts part of the review queue. LADBS correction cycles routinely add four to eight weeks to a project. An ADU documentation service that has processed ADU permit sets through LADBS before knows exactly which items trigger corrections and prepares the package to avoid them from the start. That LADBS-specific experience is worth asking about directly when you’re evaluating providers.

What ADU Documentation Service and Permit-Ready Plans Cost in Los Angeles

Cost transparency is rare in this industry, so here are honest numbers broken into components so you can budget accurately and spot proposals that are underpriced because they’re under-scoped.

How Fees Break Down Across the Service Scope

ADU documentation costs in LA County generally fall into two buckets. Field measurement and existing-conditions work typically runs between $800 and $2,500 depending on property size and complexity. The full architectural plan set, including all required drawings and supporting documents, commonly ranges from $3,500 to $10,000 or more for a permit-ready package. Full-service packages that include engineering coordination, Title 24 preparation, and plan check response support can reach the mid-teens or higher for complex projects. Note that high-complexity or hillside projects may exceed these bands. These figures don’t include city permit fees, which add another $2,000 to $12,000 depending on the valuation and the specific jurisdiction within LA County.

Where Full-Service Pricing Pays Off

A lower-cost provider that offers drafting only, without field measurement, shifts the measurement responsibility to you. That’s a significant liability if your numbers are off, because dimensional errors on the site plan are one of the most common correction triggers at LADBS. Full-service firms that handle the site visit and the complete CAD package cost more upfront, but they reduce the risk of correction-driven delays that consume both time and money during plan check. For a project where permit fees, contractor schedules, and carrying costs are already on the line, a clean first submittal has real financial value that the fee difference often doesn’t capture.

How to Evaluate an ADU Documentation Service Before You Hire

Not every drafting service has the same depth of LADBS experience. Some firms produce attractive plans that repeatedly fail plan check because the preparer doesn’t understand the specific requirements of the city or district covering your parcel. Two questions will tell you most of what you need to know before signing a contract.

The Two Questions That Separate Capable Providers from the Rest

First, ask how many ADU permit sets the provider has submitted specifically through LADBS or the particular city department that covers your property. Requirements vary meaningfully between the City of Los Angeles, unincorporated LA County parcels, Pasadena, Santa Monica, and other local jurisdictions. A firm that learns your city’s plan check process on your project is doing that learning at your expense. Second, ask whether their scope includes ADU permit expediting service support, meaning plan check response assistance if LADBS issues a correction notice after submission. A service that hands you the drawings and disappears leaves you managing the correction cycle without the technical expertise to respond to it efficiently.

Why As-Built Drawings Los Angeles Is Worth a Direct Conversation

As-Built Drawings Los Angeles has handled ADU documentation, garage conversion plan sets, and JADU permit packages across LA County for decades. The workflow covers every phase: 3D laser scanning or manual field measurement, AutoCAD and Revit drafting, and a final permit-ready plan set formatted for LADBS submittal. The team brings hands-on familiarity with local zoning rules and city-specific submittal requirements built through years of processing permit sets across jurisdictions throughout the county. For homeowners who want a single vendor to handle everything from the site visit to the permit window, that local depth is a meaningful advantage over generalist drafting firms working remotely from out-of-area. Request a scoped ADU documentation quote directly to discuss your property and get a clear picture of what your project requires before any work begins.

Pre-Approved ADU Plans and What ADU Permit Documentation They Still Require

Los Angeles County offers a pre-approved ADU Standard Plans Program, and several cities within the county offer similar programs. Using a pre-approved design can reduce plan check time and, in some cases, lower the plan check fee. But these programs are frequently misunderstood, and that misunderstanding leads homeowners to underestimate the documentation work that remains.

What a Pre-Approved ADU Plan Actually Means

A pre-approved plan set has already passed the building department’s design review for that specific plan type. The building design is approved; your lot is not. Before the application can move forward, you still need site-specific ADU permit documentation: a site plan showing the existing house, property lines, setbacks, easements, utility routing, and proposed ADU placement. You also need site-specific Title 24 energy calculations, any required agency referral items, and a completed plot plan approved by the relevant planning department. The architectural design drawings are handled by the pre-approved set; all the site-specific documentation is still your responsibility.

Why ADU Documentation Services Still Matter for Pre-Approved Projects

A homeowner who selects a pre-approved ADU design but attempts to prepare the site-specific documents without professional help is taking on the same risk that causes most application rejections: an incomplete submittal. The site plan must be drawn to city standards with correct dimensions, accurately reflecting the existing house, proposed ADU placement, property lines, easements, and utility routing. An ADU documentation service handles exactly this scope, making it faster and cleaner to pair a pre-approved design with a properly prepared, site-specific package that LADBS will accept on the first pass.

The Bottom Line on ADU Documentation

A complete ADU documentation service delivers field measurement, existing-conditions drawings, a full permit-ready plan set, and, from the right provider, plan check support through approval. The biggest risk in the ADU permitting process is an incomplete initial submittal, and a qualified local service eliminates that risk before it becomes a four-to-eight-week delay sitting in a correction queue.

For LA County homeowners ready to move from idea to permit-ready drawings, As-Built Drawings Los Angeles offers the full scope: site visit, field documentation, AutoCAD and Revit production, and LADBS-compliant deliverables built on decades of local permitting experience. Schedule a site visit or reach out to our team to discuss your property, and we’ll walk you through exactly what your project requires before any work begins.