Getting Your ADU Approved: The Permit Process Explained
You've got your architectural plans, structural engineering, and Title 24 report. Now it's time to submit everything to the city and get your building permit. This is where many DIY builders get stuck — but it doesn't have to be painful.
What You'll Submit
A complete ADU permit application typically includes:
- Permit application forms (city-specific)
- Architectural plans (site plan, floor plans, elevations, sections)
- Structural plans and calculations
- Title 24 energy compliance report
- Soils/geotechnical report (if required)
- Plot plan / survey showing your ADU's location on the lot
- Grading plan (if significant earth movement is needed)
- Utility plans (sewer, water, electrical connections)
The Review Process
Initial Screening (1-3 days)
The building department checks that your submittal is complete. Missing documents mean immediate rejection and starting over.
Plan Check (3-8 weeks)
Multiple departments review your plans simultaneously:
- Building & Safety: Structural adequacy, fire safety, accessibility
- Planning/Zoning: Setbacks, height limits, lot coverage, parking
- Fire Department: Sprinkler requirements, access, smoke detectors
- Public Works: Sewer connections, drainage, sidewalk impacts
- Health Department: Septic systems (if applicable)
Corrections (1-3 rounds)
Almost every project receives correction comments. Common ones include:
- Insufficient structural details at connections
- Missing fire-rated assemblies
- Window egress requirements
- Drainage plan inadequacies
- Title 24 calculation discrepancies
Each round of corrections can add 2-4 weeks to the process.
Permit Issuance
Once all corrections are resolved and fees are paid, you receive your building permit. Now you can start construction!
California's ADU Advantages
State law (SB 13, AB 68, AB 881) gives ADU builders significant advantages:
- 60-day review mandate: Cities must act on ADU applications within 60 days
- Ministerial review: ADUs that meet objective standards must be approved — no discretionary review or public hearings
- Reduced fees: Impact fees are waived for ADUs under 750 sq ft
- No parking requirements: For garage conversions and ADUs near transit
- Relaxed setbacks: State law limits rear and side setbacks to 4 feet
Common Mistakes That Delay Permits
- Incomplete submittals — missing even one document resets the clock
- Inaccurate site plans — the plot plan must precisely show property lines, setbacks, and existing structures
- Ignoring pre-existing violations — unpermitted work on your property can complicate your ADU permit
- Wrong zoning assumptions — always verify your property's zoning before starting design
- Skipping the pre-application meeting — many cities offer free pre-submittal consultations that can save weeks
Permit Fees
Typical ADU permit fees in LA and OC range contact us for a quote by project depending on the city and project size. Some cities offer fee waivers for affordable ADUs.
Pro Tips
- Let your builder handle submittals. Experienced ADU builders know each city's requirements and quirks.
- Respond to corrections quickly. The longer you wait, the longer your project sits idle.
- Keep a paper trail. Document every interaction with the building department.
- Ask about express plan check. Some cities offer expedited review for additional fees.
Coming Up Next
Day 5: Start of Construction — what happens on Day 1 of your build, from demolition to site preparation.
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Vision ADU has navigated permits in over 50 Southern California cities. Let us handle your permits — it's included in our full-service package.
Related Vision ADU Resources
- How to Build an ADU, Day 6: Foundation
- How to Build an ADU, Day 7: Framing
- How to Build an ADU, Day 8: Electrical
- How to Build an ADU, Day 9: Plumbing
- ADU Contractor in Huntington Beach
- ADU Contractor in Santa Ana
- Los Angeles County ADU Builder
- Orange County ADU Builder
- Inland Empire ADU Builder
- 2026 ADU Cost Calculator
- All Vision ADU Service Areas