Step-by-Step ADU Permit Process in California

Getting your California ADU permit approved involves a strategic 6-phase process spanning approximately 12-20 weeks from initial research to permit in hand. Understanding each phase—and executing them correctly—is the difference between 60-day approval and 6+ month delays.

Phase 1: Pre-Application Research (1-2 Weeks)

Before investing in design, you need to confirm your property can support an ADU and understand the specific requirements that will govern your project.

Step 1.1: Verify Property Eligibility

Check Zoning Designation

• Look up your property's zoning on your city's zoning map (usually available online)
• Confirm ADUs are permitted in your zone (residential zones almost always allow ADUs under state law)
• Identify any overlay zones (historic district, coastal zone, fire hazard area)

Confirm Property Characteristics

• Lot size: Minimum requirements vary, but state law allows ADUs on any lot with existing or proposed dwelling
• Existing structures: Primary dwelling must exist or be proposed concurrently
• Easements: Identify any easements that may restrict building location
• Utilities: Confirm water, sewer, and electrical service availability

Step 1.2: Research City-Specific Requirements

Find Your City's ADU Ordinance

• Search "[City Name] ADU ordinance" or check municipal code
• Look for ADU-specific webpage on city planning department site
• Download any ADU handouts, checklists, or application guides

Key Requirements to Identify

• Maximum ADU size (state law: 1,200 sq ft for detached, 1,000 sq ft for attached, 850 sq ft for studio/1BR)
• Setback requirements (state law: 4 ft rear and side for new construction)
• Height limits (varies by city, typically 16-25 ft)
• Parking requirements (often waived within 1/2 mile of transit)
• Design standards (materials, colors, architectural compatibility)

Step 1.3: Order Property Survey

Critical: A current property survey is the foundation of your entire permit package. Skipping this step is the #1 cause of plan corrections and delays.

What to Order

• ALTA/NSPS Land Title Survey (most comprehensive) or
• Boundary Survey with Topography (minimum for most cities)

Survey Should Include

• Property boundaries with monuments
• Existing structures with dimensions
• Topographic contours (1-2 ft intervals)
• Easements of record
• Utility locations
• Trees (if protected tree ordinance applies)

Timeline: 1-3 weeks depending on surveyor availability

Cost: $800-$2,500 depending on lot size and complexity

Step 1.4: Schedule Pre-Application Meeting

Most California cities offer free or low-cost pre-application meetings for ADU projects. This is highly recommended but not always required.

Benefits of Pre-App Meeting

• Confirm ADU eligibility for your specific property
• Identify any special requirements (historic review, coastal permit, etc.)
• Get clarity on city-specific submittal requirements
• Establish relationship with planning staff
• Document city's verbal guidance (helpful if issues arise later)

What to Bring

• Property address and APN
• Preliminary site plan showing proposed ADU location
• Basic ADU specifications (size, height, type)
• List of questions about requirements

Phase 2: Design & Documentation (4-6 Weeks)

This is where your ADU takes shape on paper. The quality of your design documentation directly determines permit timeline and construction success.

Step 2.1: Hire Your Design Team

Option A: Full-Service Drafting Firm (Recommended)

A firm like Andalusia Drafting coordinates all professionals and delivers a complete package:

• Architectural design and drafting
• Structural engineering coordination
• Title 24 energy compliance
• MEP (mechanical, electrical, plumbing) plans

Advantage: Single point of contact, coordinated documents, faster timeline

Option B: Hire Separately

• Architect or designer for plans
• Structural engineer for structural calculations and details
• Energy consultant for Title 24 compliance
• MEP engineer if required by city

Challenge: Coordination burden falls on homeowner; conflicts between documents cause corrections

Step 2.2: Develop Architectural Plans

Required Plan Sheets (Typical)

Sheet	Description
Cover Sheet	Project info, code summary, sheet index, vicinity map
Site Plan	Property boundaries, setbacks, existing and proposed structures, utilities
Floor Plan	Room layout, dimensions, door/window schedule, fixture locations
Roof Plan	Roof shape, slopes, drainage, materials
Exterior Elevations	All four sides showing materials, heights, windows, doors
Building Sections	Cut-through views showing construction, ceiling heights
Details	Construction details for windows, doors, connections

Step 2.3: Structural Engineering

California requires stamped structural calculations and details for all new ADU construction.

Structural Package Includes

• Foundation plan and details
• Framing plans (floor, wall, roof)
• Structural calculations
• Seismic design compliance
• Connection details

Special Considerations

• Hillside properties: May require geotechnical report
• Existing structures: Require as-built verification for attached ADUs
• Second-story ADUs: More complex structural requirements

Step 2.4: Title 24 Energy Compliance

All California ADUs must comply with Title 24 Building Energy Efficiency Standards (2022 code, with 2025 updates taking effect).

Required Documentation

• CF-1R (Certificate of Compliance): Proves design meets energy code
• Energy calculations: Software-generated analysis
• HERS documentation: Required for performance compliance path

Key Title 24 Requirements for ADUs

• Insulation values (R-values for walls, roof, floor)
• Window specifications (U-factor, SHGC)
• HVAC efficiency
• Water heating (heat pump preferred)
• Lighting (LED required)
• Solar-ready or solar photovoltaic (may apply)

Learn more about Title 24 compliance requirements →

Step 2.5: MEP Plans

Requirements for Mechanical, Electrical, and Plumbing plans vary by city.

Minimum Requirements (Most Cities)

• Electrical panel location and sizing
• Plumbing fixture locations and connections
• HVAC equipment location and sizing
• Smoke/CO detector locations

Full MEP Plans (Some Cities)

• Complete electrical layout with circuits
• Plumbing isometric diagrams
• HVAC duct layout and calculations
• Load calculations

Phase 3: Pre-Submittal Review (3-5 Days)

Before submitting to the city, a thorough internal review catches errors that would otherwise cause corrections and delays.

Step 3.1: Internal Quality Control

Cross-Check All Documents

• Verify dimensions match between architectural and structural plans
• Confirm Title 24 specifications match plan details
• Check that site plan matches survey data
• Ensure all required sheets are included
• Verify all signatures and stamps are in place

Code Compliance Review

• Setbacks meet city requirements
• Height complies with limits
• Size within allowed maximum
• Parking addressed (or exemption documented)
• Fire safety requirements met

Step 3.2: Prepare Submittal Package

Typical Submittal Requirements

• Completed application form
• Plan sets (number of copies per city requirements)
• Property survey
• Title 24 documentation
• Structural calculations
• Owner authorization (if applicant is not owner)
• Application fee payment

Electronic Submittal (Most Cities)

• PDF files meeting city specifications (typically 24x36, specific naming convention)
• File size limits (compress if needed)
• Separate files for each discipline (architectural, structural, etc.)

Phase 4: Permit Application Submittal (1-2 Days)

Step 4.1: Submit Application

Online Submittal (Preferred)

Most California cities now accept or require electronic submittals:

• Los Angeles: LADBS ePlanLA system
• San Francisco: DBI Permit Portal
• San Diego: DSD Online Submittal
• San Jose: ePlan system

In-Person Submittal

Some cities or complex projects may require in-person submittal:

• Schedule appointment if required
• Bring all required copies
• Be prepared for over-the-counter review

Step 4.2: Pay Initial Fees

Initial submittal fees typically include:

• Plan check fee: $500-$3,000 (often percentage of permit fee)
• Technology/processing fee: $50-$200

Remaining fees (permit fee, impact fees, school fees) are paid at permit issuance.

Step 4.3: Receive Confirmation

• Get permit application number
• Note assigned plan checker (if provided)
• Confirm estimated review timeline
• Set up account to track status online

Phase 5: City Review & Corrections (8-12 Weeks)

This is typically the longest phase. Your strategy during review determines whether you achieve 60-day approval or face months of delays.

Step 5.1: Completeness Review

Under SB 543 (effective 2026), cities must determine application completeness within 15 business days.

Possible Outcomes

• Complete: Application accepted for substantive review. 60-day clock starts.
• Incomplete: City identifies missing items. Must resubmit with corrections. Clock does not start until complete.

Step 5.2: Plan Check Review

Once deemed complete, your plans are reviewed by multiple departments:

Typical Review Departments

• Planning/Zoning: Setbacks, height, size, design standards
• Building: Structural, accessibility, life safety
• Fire: Sprinklers (if applicable), access, smoke detection
• Public Works: Drainage, utilities, grading
• Energy: Title 24 compliance

Timeline by City (Approximate)

• Los Angeles: 50-70 days for first review
• San Francisco: 60-90 days
• San Diego: 50-75 days
• San Jose: 35-55 days
• Sacramento: 45-65 days

Step 5.3: Respond to Corrections

Most first reviews result in some corrections. How quickly and completely you respond determines final timeline.

Correction Response Protocol

1. Review immediately: Read all comments same day you receive them
2. Clarify if needed: Contact plan checker for any unclear corrections
3. Coordinate response: Ensure all consultants address their portions
4. Respond within 48-72 hours: Fast response maintains queue priority
5. Document changes: Use clouding/revision marks per city requirements

Common Corrections (and How to Avoid Them)

• Setback discrepancies: Use accurate survey data
• Missing details: Include comprehensive construction details
• Title 24 conflicts: Ensure CF-1R matches plan specifications
• Structural inconsistencies: Coordinate architectural and structural plans
• Incomplete information: Follow city's submittal checklist exactly

Step 5.4: Re-Review Cycles

If corrections are substantial, plan checkers may require multiple review cycles. Each cycle adds 1-3 weeks.

Minimizing Re-Review Cycles

• Address ALL corrections in first response (don't submit partial fixes)
• Verify corrections don't create new conflicts
• Include cover letter summarizing all changes
• Request plan checker review of complex corrections before formal resubmittal

Phase 6: Permit Issuance (1-3 Days)

Step 6.1: Plan Approval

Once all corrections are resolved, you'll receive notice that plans are approved and ready for permit issuance.

Step 6.2: Pay Final Fees

Fees Due at Issuance

• Building permit fee: Based on valuation
• Impact fees: If ADU >750 sq ft
• School fees: If applicable
• Utility connection fees: If new connections required

See our complete ADU permit cost breakdown for detailed fee information.

Step 6.3: Receive Permit

What You'll Receive

• Permit card: Must be posted at job site
• Approved plans: Stamped set for construction
• Inspection card: Lists required inspections
• Conditions of approval: Any special requirements

Step 6.4: Prepare for Construction

Before Breaking Ground

• Hire licensed contractor (if not owner-builder)
• Schedule utility locates (call 811)
• Order materials
• Post permit card and approved plans at site
• Schedule first inspection (typically foundation)

Complete Timeline Summary

Phase	Duration	Cumulative
Phase 1: Pre-Application	1-2 weeks	1-2 weeks
Phase 2: Design & Documentation	4-6 weeks	5-8 weeks
Phase 3: Pre-Submittal Review	3-5 days	6-9 weeks
Phase 4: Submittal	1-2 days	6-9 weeks
Phase 5: City Review	8-12 weeks	14-21 weeks
Phase 6: Issuance	1-3 days	14-21 weeks