AB 2533 lets California homeowners legalize an unpermitted ADU or garage conversion built before January 1, 2020 without penalties, fines, or impact fees, as long as it meets basic health and safety standards. It uses a focused safety checklist rather than a full current-code retrofit. Here’s how to legalize an unpermitted ADU under AB 2533.
If you built an ADU before 2020 without permits, you’re not alone. Thousands of California homeowners have unpermitted garage conversions, backyard cottages, or basement apartments. Most live with constant worry about code enforcement, fines, or forced removal.
Assembly Bill 2533 changed that. Effective January 1, 2025, the law creates a clear path to legalize unpermitted ADUs without penalties or excessive fees. The process focuses on safety, not rigid code enforcement.
Here’s everything you need to know about AB 2533 and how to get your ADU permitted.
Here at GreatBuildz, a free service that connects homeowners throughout California with reliable, thoroughly screened ADU contractors, we are well versed in ADU permits and helping homeowners every step of the way.
What is AB 2533?
Assembly Bill 2533, authored by Assemblymember Juan Carrillo and signed September 28, 2024, prohibits cities from denying permits for unpermitted ADUs based solely on code violations. Cities can only deny applications if violations create genuine health or safety risks.
This represents a major shift. Previous amnesty programs covered only ADUs built before January 1, 2018. AB 2533 extends eligibility to January 1, 2020, helping thousands more homeowners.
The law covers all unpermitted ADU types:
- Detached backyard units
- Garage conversions (see our Los Angeles garage conversion guide for LA-specific details)
- Basement or attic conversions
- Junior ADUs (500 sq ft or less within the main house)
- Above-garage units
- Converted pool houses or workshops
Key protections:
- No penalties for previous unpermitted status
- No retroactive impact fees or connection charges
- Right to confidential pre-inspection before applying
- Cities must provide clear checklists and guidance
- Protection from code enforcement during legalization
Eligibility Requirements
You qualify if your ADU or JADU was built or converted before January 1, 2020. This includes units with no permits, active code enforcement cases, or Notices of Violation.
The only disqualifier is “substandard” classification under California Health and Safety Code Section 17920.3. Substandard buildings have serious safety hazards:
- Major structural defects threatening collapse
- Serious fire hazards (inadequate exits, unsafe heating)
- Dangerous electrical systems posing an immediate risk
- Complete lack of emergency egress
- Severe habitability issues (no running water, extreme deterioration)
Minor code violations don’t disqualify you. Missing smoke detectors, needed GFCI outlets, or undersized egress windows can be fixed during the process.
Proving construction date: Use utility connection records, property tax assessments, Google Earth historical imagery, dated photos, contractor invoices, or real estate disclosure documents.
The 7-Step Legalization Process
Step 1: Verify Eligibility
Confirm your ADU was built before January 1, 2020. Gather documentation proving the construction date.
Step 2: Get a Confidential Pre-Inspection
AB 2533 allows you to hire a licensed contractor to inspect your ADU before submitting an application. This confidential inspection reveals what needs fixing and provides accurate cost estimates without triggering code enforcement.
Cost: $500 to $1,500, often included in contractor quotes.
Step 3: Prepare Required Documents
Your application needs:
- Proof of construction date
- Site plan showing ADU location and setbacks
- Floor plan with labeled rooms, dimensions, and utilities
- Completed Substandard Housing Checklist (provided by city)
- Exterior elevations, if required
Most homeowners need an architect or designer for proper drawings. Cost: $3,000 to $8,000.
Step 4: Submit Application
Contact your local building department. Cities must post clear information online about the AB 2533 process.
Permit application fee: $570 to $800 (varies by city).
Step 5: City Safety Inspection
An inspector evaluates your ADU against Health and Safety Code Section 17920.3. This isn’t full code compliance for new construction. Inspectors check basic safety:
- Smoke detectors and carbon monoxide alarms
- Safe electrical (GFCI outlets, no exposed wiring)
- Emergency egress (properly sized windows and doors)
- Functional plumbing and heating
- Structural soundness
- Sanitary conditions
The inspector provides a list of required corrections.
Step 6: Make Required Upgrades
The city issues a permit for specific safety improvements. Ensure you only hire licensed contractors for the work.
Common upgrades and costs:
- Smoke/CO detectors: $100 to $300
- GFCI outlets: $150 to $400
- Egress window improvements: $500 to $3,000
- Electrical panel upgrade: $1,500 to $3,000
- Structural repairs: varies
- Ventilation or heating: $500 to $2,500
Total for upgrades: $10,000 to $70,000+, depending on condition.
Step 7: Final Inspection and Approval
Schedule final inspection after completing the work. Upon approval, you receive a Certificate of Occupancy or Certificate of Compliance.
Your ADU is now legal. You can legally rent it, obtain proper insurance, include it in refinancing, and avoid code enforcement concerns.
Timeline: 2 to 6 months from application to approval.
Legalization Costs
Fees waived:
- Penalties or fines for unpermitted status
- Retroactive impact fees
- Connection or capacity charges (unless new infrastructure needed)
Actual costs:
| Expense | Range |
| Permit fees | $570 – $800 |
| Architect/designer | $3,000 – $8,000 |
| Pre-inspection (optional) | $500 – $1,500 |
| Safety upgrades | $2,000 – $30,000+ |
| Structural engineer | $2,000 – $5,000 |
| Total | $10,000 – $50,000 |
Legal ADUs add 20% to 30% more property value than unpermitted units. Legal rental income ranges from $1,800 to $4,500 monthly in most California markets. Proper insurance coverage and refinancing options become available. Compare this to the cost of demolition and rebuilding. Starting from scratch costs $150,000 to $400,000. Code violation fines can reach $500 to $5,000 daily in some cities.
City-Specific Implementation
Los Angeles
LADBS processes AB 2533 applications. The city has tens of thousands of unpermitted ADUs. Pre-application consultations available. For LA garage conversion specifics, see our complete guide to legalizing an unpermitted garage.
San Diego
Information Bulletin 242 outlines the process. Works alongside SB 1226 for older units. Coastal Act areas require additional approvals.
Bay Area
- Berkeley: Pilot program through December 31, 2028 (single-family lots only)
- Hayward: Confidential consultations, $570 flat fee plus state fees
- Foster City, Milpitas: Streamlined processes with online guidance
- Other cities: Check individual websites for AB 2533 implementation
To find your city’s process, you can do it by searching “[city name] AB 2533” or “Legalize unpermitted ADU in [city name]” or contact your building department directly.
Why Permit Your ADU Now
Financial benefits:
- Legal rental income immediately available
- Property value increase of 20% to 30%
- Access to refinancing and home equity
- Tax deductions for legitimate expenses
Legal protection:
- Eliminates risk of $500 to $5,000+ daily fines
- Prevents forced demolition
- Provides landlord-tenant law protections
- Enables proper insurance coverage
Safety and peace of mind:
- Ensures proper safety measures
- Protects against personal liability
- Provides tenant protections
- Eliminates enforcement concerns
Timing advantages:
- Cities improving processes through 2028
- Contractor availability remains reasonable
- Real estate market heavily discounts unpermitted ADUs
FAQ
Can I rent my ADU during legalization?
You’re protected from penalties during the process. Most homeowners continue renting.
What if I have active code enforcement?
AB 2533 applies to units with existing Notices of Violation or enforcement cases.
How long does the process take?
2 to 6 months typically. Complex cases requiring extensive upgrades may take longer.
Will legalization affect property taxes?
It may increase the assessed value. Consult a tax professional for your specific situation.
What if my city hasn’t posted AB 2533 information?
They’re required by law. Contact your building department and request AB 2533 guidance.
If you’re wanting to take the next step in your ADU process, we are here to help. We at GreatBuildz specialize in making sure your home construction project goes smoothly every step of the way.
Call us at 818.317.3567 or Submit Your Project Today. We’ll match you with vetted contractors so you can move forward with confidence and clarity.
