--- title: "LADBS ADU Plan Check Requirements Explained" description: "Learn exactly what the Los Angeles Department of Building and Safety checks during ADU plan review." url: "https://adubuilder-losangeles.com/ladbs-adu-plan-check-requirements/" --- # LADBS ADU Plan Check - What Reviewers Look For ## Why Plan Check Is the Make-or-Break Stage Most accessory dwelling unit (ADU) projects in Los Angeles stall not during construction but during plan review. The Los Angeles Department of Building and Safety (LADBS) reviews submitted drawings to confirm that every element, from structural framing to plumbing layout, meets California Building Code and city ordinance requirements before a single shovel breaks ground. Getting that review right the first time saves weeks, sometimes months, of back-and-forth with plan checkers. Understanding what reviewers actually scrutinize gives you a practical target. The sections below break down each major area of focus so you can prepare drawings that move through LADBS ADU plan check requirements without unnecessary corrections. --- ## Site and Zoning Compliance Reviewers open every submittal by checking whether the proposed ADU is even permitted on the lot. They verify zoning classification, lot size, and whether an existing primary dwelling is present, since California state law requires a lawfully established primary residence on the same parcel for most detached ADU types. Setbacks are checked next. Los Angeles requires a minimum 4-foot rear and side setback for detached ADUs. Drawings must dimension these setbacks clearly on the site plan, with the property lines identified from recorded survey data, not estimated. Units larger than 1,200 square feet will be flagged for exceeding the state-mandated maximum regardless of how well the rest of the drawings are prepared. --- ## Architectural and Structural Documents Plan checkers review floor plans, elevations, and sections for code compliance on ceiling height, emergency egress windows, door widths, and bathroom ventilation. Each room must be labeled with its use, square footage, and dimensions. Missing room labels or vague notations like "bedroom" without window specs are common correction triggers. Structural drawings receive close attention, particularly for detached ADUs built on new foundations. Reviewers confirm that foundation type, footing size, and anchor bolt placement are sized to the soil conditions on the site. If a soils report or geotechnical investigation is required for the parcel, it must be referenced on the structural sheets with the engineer of record's stamp and signature visible. ### Title-24 Energy Compliance California's Title-24 energy standards apply to all new ADU construction and to conversions that change the thermal envelope. The plan check package must include a completed CF-1R (Certificate of Compliance) form generated by approved software. Reviewers verify that insulation R-values, window U-factors, and mechanical equipment efficiency ratings on the plans match the values declared in the energy compliance report. Missing or mismatched energy documentation is one of the most common reasons an ADU submittal comes back with a correction notice on the first round. --- ## Mechanical, Electrical, and Plumbing Systems MEP drawings must show how the ADU connects to or separates from the main dwelling's utilities. For a detached ADU, reviewers look for a dedicated electrical panel or a clearly documented connection to the main service, sized for the new load. The panel schedule must list all circuits with breaker sizes. Plumbing sheets need to show fixture unit counts, drain line sizes, cleanout locations, and how the sewer lateral ties into the existing system. Utility connection points must be labeled with pipe sizes and materials. Los Angeles requires separate gas shutoffs for ADUs, so reviewers confirm that detail appears on the mechanical sheets. --- ## LADBS ADU Requirements Checklist A complete submittal to LADBS typically needs the following documents: - Completed LADBS application forms - Site plan dimensioning setbacks, lot coverage, and existing structures - Architectural floor plans, elevations, and building sections at a minimum 1/4-inch scale - Structural calculations and drawings stamped by a licensed California structural engineer - Title-24 energy compliance report (CF-1R and CF-2R) - Plumbing, mechanical, and electrical plans - Soils report if required by the parcel's conditions - Owner authorization or contractor license documentation Missing any of these at intake means the submittal is rejected before a reviewer touches it, adding days to your timeline before the clock even starts. --- ## What Documents Do I Need for LADBS ADU Plan Check **The core package is a site plan, full architectural drawings, structural engineering, and Title-24 energy compliance documentation.** Depending on the project type, you may also need a soils or geotechnical report and a stormwater drainage plan. Garage conversion ADU projects sometimes require a report confirming the existing slab thickness and condition before a structural engineer can certify the foundation. Using LADBS pre-approved standard ADU plans can reduce what you need to prepare from scratch. Those plans come with pre-stamped structural and energy documentation, so you primarily supply site-specific sheets showing how the standard plan fits your property. --- ## ADU Plan Check Fees LADBS LADBS plan check and permit fees for ADUs typically total between $10,000 and $25,000 for a standard detached project, covering plan check, building permit issuance, and associated city fees. This range reflects variation in square footage, construction type, and whether the project triggers additional departmental reviews such as fire or sanitation. ADUs under 750 square feet are exempt from local agency impact fees in California under AB 68 and related state legislation, which can produce meaningful savings for projects sized specifically to stay below that threshold. Always confirm current fee schedules directly with LADBS, since fee structures are subject to revision. --- ## How Long Is LADBS ADU Plan Check **Standard LADBS ADU plan check turnaround runs 4–12 weeks for a conventional submittal.** Projects using LADBS-approved standard plans can move through review in as little as 1–4 weeks because the structural and energy documentation has already been vetted. The gap between those two timelines is the strongest practical argument for using pre-approved plans on a straightforward site. Correction cycles extend the timeline significantly. Each round of corrections followed by resubmission adds weeks, so submitting a complete and accurate package the first time is not just ideal but financially material. If your general contractor is priced for a construction start date, a correction-driven delay can disrupt that schedule and affect subcontractor availability. --- ## Common Reasons Submittals Come Back with Corrections Plan checkers most frequently flag missing dimensions on site plans, structural details that reference a soils report that was not included, Title-24 reports generated for a different version of the plans, and electrical load calculations that do not account for the ADU's full square footage. Each of these is preventable with a thorough internal review before submission. Working with a licensed architect who has prior LADBS ADU experience reduces the likelihood of these errors. Architects familiar with current LADBS conventions know which notes, callouts, and detail numbers reviewers expect to see on each sheet type. The architectural and design fee range of $8,000–$20,000 for a typical ADU project is partly justified by the cost savings from a cleaner first submission. ## Frequently Asked Questions ### LADBS ADU Requirements Checklist A complete LADBS ADU submittal includes a site plan with dimensioned setbacks, architectural floor plans and elevations at 1/4-inch scale, stamped structural drawings and calculations, a Title-24 energy compliance report (CF-1R and CF-2R), plumbing and electrical plans, and owner or contractor authorization. A soils report is also required on certain parcels. Missing any of these at intake results in rejection before review begins. ### What Documents Do I Need for LADBS ADU Plan Check? **The core package is a site plan, full architectural drawings, structural engineering stamped by a licensed California engineer, and Title-24 energy compliance documentation.** Garage conversion ADU projects may also require a slab condition report. Using LADBS pre-approved standard ADU plans reduces what you must prepare from scratch, since structural and energy documents for those plans are already vetted. ### ADU Plan Check Fees LADBS LADBS plan check and permit fees for a standard detached ADU typically total $10,000–$25,000, covering plan check, building permit issuance, and associated city fees. ADUs under 750 square feet are exempt from local agency impact fees in California under AB 68. Confirm current fee schedules directly with LADBS, as these figures are subject to change. ### How Long Is LADBS ADU Plan Check? **Standard LADBS ADU plan check turnaround is 4–12 weeks for a conventional submittal.** Projects using LADBS pre-approved standard plans can receive approval in as little as 1–4 weeks. Each correction cycle adds additional weeks, so submitting a complete and accurate package on the first attempt has a direct impact on your construction start date. ### What Are the Most Common Reasons an ADU Plan Check Submittal Comes Back with Corrections? **The most frequent correction triggers are missing dimensions on the site plan, structural details that reference a soils report not included in the package, Title-24 energy reports generated for an earlier version of the plans, and electrical load calculations that undercount the ADU's square footage.** Each is preventable through a thorough review before submission, ideally with a licensed architect who has prior LADBS ADU experience.