AB 1332: Pre-Approved ADU Plans
30-day permits, lower costs, and streamlined approvals — how California's pre-approved plan law changes ADU permitting.
30days
Max approval time
All
CA cities required
Jan 2025
Program deadline
1,200sf max
Detached ADU
What Is AB 1332?
Assembly Bill 1332, signed into law October 11, 2023, adds Government Code §65852.27 requiring every California local agency — cities, counties, and charter cities — to establish a program for pre-approving ADU plans.
The law creates a two-track system:
Pre-Approval Track
Anyone can submit non-site-specific ADU plans for pre-approval. Agencies review against standard ADU requirements, then post approved plans on their website.
Fast-Track Permits
When a homeowner uses a pre-approved plan for a detached ADU, the agency must approve or deny within 30 days of a complete application (ministerial review only — no public hearings).
California ADU Size Limits (Statewide)
| ADU Type | Maximum Size | Notes |
|---|---|---|
| Detached (new construction) | 1,200 sq ft | Must allow at least 800 sq ft regardless of lot size |
| Attached | 50% of primary dwelling | Up to 850 sq ft (1BR) or 1,000+ sq ft (multi-BR) |
| Conversion (garage, etc.) | No max | Existing structure footprint |
| JADU (Junior ADU) | 500 sq ft | Must be within primary dwelling |
| Efficiency unit | 190 sq ft minimum | Studio-style layout |
Cities with Pre-Approved ADU Plans
All California cities were required to have programs by January 1, 2025. Here are cities that have published pre-approved plan libraries:
This list is not exhaustive. Check your city's planning department website for their specific pre-approved plan program.
How to Use a Pre-Approved Plan
Browse Your City's Library
Visit your local planning department website and find their pre-approved ADU plan catalog. Plans include floor layouts, elevations, and specifications.
Select a Plan That Fits Your Lot
Choose a plan that meets your needs and fits your lot dimensions. Pre-approved plans are non-site-specific, so you'll adapt it to your property.
Prepare Site-Specific Documents
Add your site plan, property survey, energy/solar calculations, and utility connections to the pre-approved design package.
Submit for Fast-Track Permit
File your complete application. The agency must approve or deny within 30 days using ministerial (staff-level) review — no public hearings or discretionary decisions.
Begin Construction
Once approved, pull your building permit and start construction. The same fees apply as a standard ADU permit for the same size unit.
Benefits of Pre-Approved Plans
Faster Approvals
30-day turnaround vs. 60-90+ days for custom designs
Lower Design Costs
Skip $5K-$15K in architect fees by using vetted plans
Reduced Risk
Plans already meet local standards — fewer revision cycles
No Public Hearings
Ministerial approval only — staff review without discretionary delay
Recent Updates (2025–2026)
- • SB 477 (2024) recodified ADU laws to Government Code §66310-66342 with minor updates to §65852.27
- • SB 543 (2025) clarified interior livable square footage calculations and added fee exemptions for ADUs under 500 sq ft
- • HCD Handbook Update (March 2026) provides updated guidance on pre-approved plan programs and ministerial review timelines
- • SANDAG published a comprehensive AB 1332 implementation guide (June 2025) for San Diego County jurisdictions
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