How to Win ADU Plan Approval Without Revisions

The Secret to First-Pass ADU Plan Approval

Getting your ADU plans approved on the first submission without any revisions is the holy grail of the permitting process. While it might seem rare, it is absolutely achievable with the right preparation, the right team, and a systematic approach to plan preparation. Homeowners who achieve first-pass approval save an average of 2 to 4 months on their project timeline and $5,000 to $15,000 in revision-related costs.

In this comprehensive guide, we will share the exact strategies that consistently produce zero-revision ADU plan approvals across California cities. These strategies come from years of experience working with building departments in Los Angeles, Pasadena, Long Beach, Santa Monica, and dozens of other jurisdictions.

Every piece of advice here is practical and actionable. By the time you finish reading, you will know exactly what to include in your plans, how to organize your submittal package, and which common mistakes to avoid entirely.

Step 1: Pre-Design Research and Due Diligence

The work of getting first-pass approval begins long before your architect draws a single line. Thorough pre-design research is the foundation of a clean submittal.

Property Research Checklist

Before starting any design work, gather the following information about your property:

• Current zoning designation: Use your city's zoning lookup tool (ZIMAS in Los Angeles) to determine the exact zoning code for your property
• Overlay zones: Identify any specific plans, historic districts, hillside ordinances, or coastal zones that apply
• Lot size and dimensions: Obtain a current property survey showing exact lot dimensions, easements, and right-of-way lines
• Existing structures: Document all existing buildings, including square footage, height, and setbacks from property lines
• Utility locations: Identify water, sewer, gas, and electrical connection points and easements
• Tree survey: Document all protected trees (species, size, and location) as they may affect ADU placement
• Soil conditions: Check if your property is in a liquefaction zone, landslide area, or has expansive soils that require special foundation design

This research typically takes 1 to 2 weeks but can save you months of revisions later. The cost of a property survey ($500 to $1,500) and a preliminary geotechnical investigation ($1,500 to $3,000) is a fraction of what you will spend on revision cycles.

Contact the Building Department Early

Many California building departments offer free or low-cost preliminary consultations. During this meeting, you can discuss your project scope, confirm zoning requirements, and ask about specific issues like property line concerns or setback requirements. In Los Angeles, you can schedule a pre-application consultation through LADBS. Other cities like Burbank, Glendale, and Torrance offer similar programs.

Come prepared with a basic site plan showing your proposed ADU location, approximate size, and relationship to existing structures. The plan checker may identify potential issues on the spot, saving you from learning about them weeks later in a correction letter.

Step 2: Assemble the Right Design Team

The quality of your design team is the single most important factor in achieving first-pass approval. Here is who you need and what to look for:

Architect or Designer

For ADU projects, you need a designer who has specific experience with ADU permitting in your city. Ask potential architects the following questions:

• How many ADUs have you designed and permitted in this city specifically?
• What is your average number of revision cycles?
• Do you prepare the complete submittal package (including Title 24, structural coordination, grading)?
• Will you attend any plan check meetings if needed?
• Are your revision fees included in your base price or charged separately?

An experienced ADU designer will typically charge $5,000 to $15,000 for a complete set of plans, depending on the complexity and size of the project. This may seem like a significant investment, but compare it to the cost of multiple revision cycles with an inexperienced designer. See our detailed guide on choosing the right ADU professional.

Structural Engineer

A licensed California structural engineer (SE or PE with civil/structural designation) is essential. They should have experience with wood-frame residential construction and California seismic requirements. Verify their license through the California Board for Professional Engineers.

Title 24 Energy Consultant

A certified energy analyst (HERS rater or CEC-certified) will prepare your Title 24 compliance documentation. This specialist ensures that your ADU meets California's energy efficiency requirements and coordinates with your architect to verify that the plans match the energy report.

Team Member	Typical Cost	Critical Deliverable
Architect/Designer	$5,000 - $15,000	Complete construction documents
Structural Engineer	$2,000 - $5,000	Structural calculations and details
Title 24 Consultant	$500 - $1,500	Energy compliance forms (CF-1R)
Surveyor	$500 - $1,500	Property survey with topography
Civil Engineer (if needed)	$2,000 - $4,000	Grading and drainage plan

Step 3: Prepare Bulletproof Construction Documents

Your construction documents are the package you submit to the building department. Every sheet must be thorough, accurate, and consistent with every other sheet. Here is what a complete ADU submittal package should include:

Cover Sheet

The cover sheet should include the project address, assessor's parcel number (APN), owner information, designer information, scope of work description, applicable codes (CBC 2022, CRC 2022, CPC 2022, CMC 2022, CEC 2022, Title 24), a sheet index, a general notes section, and a vicinity map. Many correction letters cite missing information that should have been on the cover sheet.

Site Plan

The site plan is arguably the most important sheet. It should show property lines with dimensions, all existing structures with setback dimensions, proposed ADU location with setback dimensions from all property lines, lot coverage calculations, floor area ratio calculations, existing and proposed utility connections (water, sewer, gas, electric), proposed grading and drainage, parking (if applicable), trash enclosure location, and landscape changes.

Floor Plans

Floor plans should be drawn at 1/4 inch equals 1 foot scale and include all room dimensions, door and window locations with sizes, plumbing fixture locations, electrical outlet and switch locations, HVAC equipment location, kitchen and bathroom layouts with clearances, and accessibility features if required.

Elevations

Show all four exterior elevations with existing and proposed grade lines, overall building height, roof slope and material, exterior finish materials, window and door sizes (matching the floor plan), and foundation details visible above grade.

Sections and Details

Include at least one building section through the most complex part of the ADU. Show the foundation type and dimensions, wall framing and insulation, ceiling/roof framing, floor-to-ceiling height, and connection details at the foundation, walls, and roof.

Step 4: Eliminate Common Mistakes Before Submittal

Before you submit, conduct a thorough internal review. Here are the most common mistakes that trigger permit revisions and how to catch them:

Consistency Check

Cross-reference every dimension, material specification, and detail across all plan sheets. If the floor plan shows a 3068 door (3 feet 0 inches by 6 feet 8 inches), verify that the same door appears on the elevations, door schedule, and structural plans. If the Title 24 report specifies R-21 wall insulation, verify that the wall section detail shows R-21 insulation.

Code Compliance Verification

Walk through each applicable code section and verify compliance. For ADUs, pay special attention to California Government Code Section 65852.2, the California Residential Code (CRC) for structural and general construction requirements, CBC Chapter 7A for fire hazard zones (if applicable), California Plumbing Code for fixture counts and venting, California Electrical Code for service size and panel requirements, and California Mechanical Code for HVAC and ventilation.

Local Requirements

Many cities have adopted local amendments to the state building codes. In Los Angeles, for example, the City has additional requirements for grading, green building, seismic retrofitting, and accessibility. Check your city's municipal code for any local amendments that may affect your ADU project.

Step 5: Submit Like a Pro

How you submit your plans matters almost as much as what is in them. Here are tips for a smooth submittal process:

Organize Your Package

Submit your plans in the order specified by the building department. Include a transmittal letter listing all documents included. Provide the correct number of plan sets (usually 2 to 4 copies plus a digital copy). Include all supplemental reports (structural calculations, Title 24 report, soils report if required, grading calculations) clearly labeled and bound separately from the plans.

Pay Attention to Formatting

Use standard sheet sizes (24x36 or 30x42 inches). Use consistent title blocks on every sheet. Include your architect's or designer's license number and stamp. Number all sheets consecutively and reference them in the sheet index. Make sure all text is legible at the printed scale.

Include a Code Analysis Summary

On your cover sheet or a dedicated code analysis sheet, include a summary of key code compliance points. This shows the plan checker that you have done your homework and makes their job easier. Include zoning compliance (lot coverage, FAR, setbacks, height), building code compliance (occupancy, construction type, fire separation), and energy code compliance (Title 24 reference).

Step 6: After Submittal Best Practices

Once your plans are submitted, stay proactive. Follow up with the building department weekly to check on the status of your plan review. If you receive any corrections, respond promptly and thoroughly. Address every item in the correction letter; do not skip any. When you resubmit, include a correction response letter that references each correction item by number and explains how you addressed it.

If you disagree with a correction, do not ignore it. Contact the plan checker to discuss it. In many cases, a phone call or meeting can resolve misunderstandings and prevent additional revision cycles. If necessary, you can escalate to a supervising plan checker or the chief building official.

Real-World Case Study: Zero-Revision Approval in Los Angeles

To illustrate these principles in action, consider a recent project in the Sherman Oaks neighborhood of Los Angeles. The homeowner wanted to build a 750-square-foot detached ADU in their backyard. By following the strategies outlined in this guide, the project received plan check approval on the first review with zero corrections.

Key factors in their success included hiring a designer with 50+ permitted ADUs in LA, obtaining a current property survey before design began, scheduling a pre-application consultation with LADBS, using a comprehensive plan check list, coordinating all consultants through a single project manager, and submitting a complete, well-organized plan package with a code analysis summary.

The total permitting timeline from submittal to permit issuance was 47 days. Without the first-pass approval, this project could have easily taken 4 to 6 months. The estimated savings from avoiding revisions: $8,000 in professional fees and $6,000 in avoided construction cost escalation.

Frequently Asked Questions

Is it realistic to expect zero revisions on an ADU permit?

Yes, it is realistic, though not guaranteed. Experienced ADU designers achieve zero-revision approvals on 30% to 50% of their projects. The key is thorough preparation, a complete and consistent plan set, and proactive communication with the building department. Even when revisions do occur, well-prepared plans typically require only one minor revision cycle.

How much does it cost to have a professional prepare ADU plans?

Complete ADU plan preparation typically costs $8,000 to $25,000, depending on the size and complexity of the project. This includes architectural plans, structural engineering, Title 24 compliance, and potentially civil engineering for grading. While this may seem expensive, it is a fraction of the total project cost and pays for itself many times over in avoided revisions and delays. Explore our complete cost guide for more details.

Can I submit ADU plans myself without an architect?

In California, owner-builders can prepare and submit their own plans for single-story, wood-frame residential buildings under certain square footage thresholds without a licensed architect. However, structural calculations must still be prepared by a licensed engineer, and Title 24 compliance must be prepared by a certified analyst. Submitting plans without professional design experience significantly increases your risk of multiple revision cycles.

What if my city requires additional studies (soils report, arborist report)?

Include all required supplemental reports with your initial submittal. Submitting without required reports will result in your application being deemed incomplete, which means the processing clock will not even start. Check your city's ADU requirements list carefully and include every required document from the start.

How do I find an ADU designer with a good track record?

Ask for referrals from your local building department (some maintain lists of active ADU designers), check the Contractors State License Board for any complaints, ask potential designers for references from recent ADU clients, and review their portfolio for projects similar to yours. A good designer should be able to tell you their average number of revision cycles and provide examples of first-pass approvals.

Does the size of my ADU affect the likelihood of first-pass approval?

Larger and more complex ADUs generally face more scrutiny and have a higher chance of revisions. A simple 400-square-foot studio ADU will have fewer opportunities for errors than a 1,200-square-foot two-bedroom unit with complex structural requirements. However, the principles in this guide apply to ADUs of all sizes.

Pre-Submission Checklist: Ensure Your ADU Plans Are Approval-Ready

Before submitting your ADU permit application, use this comprehensive checklist to verify that your plans are complete and code-compliant. Addressing these items before submission dramatically reduces the chance of correction notices and resubmittal delays.

Site Plan Checklist

• Property boundaries clearly shown with dimensions from a recent survey or assessor map
• Existing structures labeled with distances to property lines
• Proposed ADU location with setback dimensions to all property lines (minimum 4 feet side and rear)
• Driveway, walkways, and access paths to the ADU clearly marked
• Utility connections (water, sewer, electrical, gas) shown from main lines to the ADU
• Existing and proposed landscaping, fences, and retaining walls noted
• Lot coverage calculation showing total impervious surface area

Architectural Plans Checklist

• Floor plan with room dimensions, door swings, and window locations
• All four exterior elevations with height dimensions and material callouts
• Roof plan showing slopes, drainage direction, and overhang dimensions
• Cross-section drawing showing foundation, wall, and roof construction details
• Kitchen and bathroom layouts with fixture locations and clearances
• Accessibility features if required by local ordinance

Engineering and Compliance Checklist

• Structural calculations signed by a licensed engineer
• Title 24 energy compliance report (CalGreen requirements)
• Fire-rated wall details for walls within 5 feet of property lines
• Soils report if required by your city or if the site has slope conditions
• Drainage plan showing how stormwater will be managed on site

For details on what happens when plan check identifies issues, read our guide on plan check property line issues.

Frequently Asked Questions

How many sets of plans do I need to submit for an ADU permit?

Most California cities require two to four sets of printed plans plus a digital copy (PDF) for ADU permit applications. Some cities have moved to fully digital submissions. Check with your local building department for their specific requirements. Submitting extra sets can speed up the process if multiple departments need to review your plans simultaneously.

Should I hire an architect or can I draw my own ADU plans?

While California does not require an architect for residential structures under a certain size, hiring a licensed architect or designer significantly improves your chances of first-time approval. Professional plans are more likely to include all required details, comply with building codes, and avoid the common errors that trigger correction notices. The cost of professional plan preparation is typically recovered through faster approvals and fewer revisions.

What is the most common reason ADU plans are sent back for corrections?

The most common correction items include incomplete Title 24 energy calculations, missing structural details at connections and load paths, insufficient setback documentation, and incomplete utility connection plans. Many of these issues can be avoided by using a qualified ADU designer or architect who has experience with your city's specific requirements. Review our detailed article on over-the-counter vs. plan check approval to understand the review process.

How long is my ADU permit valid once approved?

In most California cities, a building permit is valid for 12 to 24 months from the date of issuance. You must begin construction within this period, or the permit may expire and you will need to reapply. Some cities offer permit extensions of 6 to 12 months for an additional fee. Once construction begins, you typically have a set number of months to complete the project and obtain a final inspection.