How to Legalize an Unpermitted ADU or Garage Conversion Under AB 2533

Published August 10, 2026

AB 2533 stops California cities from denying a permit for an unpermitted ADU or garage conversion built before January 1, 2020, just because it violates a building code. Here is what the law actually requires and where it still lets a city say no.

The short answer

AB 2533, Chapter 834 of 2024, bars California cities and counties from denying a permit for an unpermitted accessory dwelling unit or junior ADU built before January 1, 2020, solely because it violates a building standard. The one exception is a genuinely substandard building under Health and Safety Code section 17920.3. Cities also cannot charge impact or connection fees to legalize it, except where new utility infrastructure is required.

Last verified: August 10, 2026

What problem this law is solving

Thousands of California homeowners converted a garage, added a bonus room, or built a backyard unit without ever pulling a permit. Some did it decades ago. Some did it because permitting felt slow or expensive. Whatever the reason, the unit exists, someone may be living in it, and it shows up as an unpermitted structure the moment a buyer's inspector, an insurance adjuster, or a code enforcement complaint finds it.

Before AB 2533, a city could refuse to legalize that structure over almost any code deficiency, no matter how minor, effectively forcing an owner to demolish a habitable space or leave it in permanent limbo. AB 2533 narrows that discretion for units built before 2020.

What the law actually requires

The bill amends Government Code section 66332. The operative rule, in the statute's own terms, is that a local agency "shall not deny a permit for an unpermitted accessory dwelling unit or unpermitted junior accessory dwelling unit that was constructed before January 1, 2020" because of a building standard violation, with one carve out.

The exception. A city can still deny or condition approval if correcting the violation is necessary to bring the structure up to the standards in Health and Safety Code section 17920.3, which defines what makes a building legally substandard. Think structural hazards, inadequate sanitation, faulty wiring, and similar conditions that threaten health and safety, not cosmetic or minor dimensional nonconformities.

No penalty for having built it without a permit. The law directs that the local agency "shall not penalize an applicant for having the unpermitted accessory dwelling unit or junior accessory dwelling unit and shall approve necessary permits to correct noncompliance." The point of entry is fixing the unit to a safe standard, not punishing the owner for the original violation.

Inspection and disclosure. Agencies may inspect the unit and provide recommendations for bringing it into compliance. But they must also publish, in advance, a public checklist of the section 17920.3 conditions that would make a building substandard, and they must tell homeowners they have the option of getting a confidential third party code inspection from a licensed contractor before ever involving the city. That lets an owner find out privately how bad the problem is before deciding whether to apply.

Fee limits. Cities cannot charge impact fees or connection and capacity charges to legalize the unit, except when new utility infrastructure is actually required to meet section 17920.3 standards, and even then only as otherwise authorized under existing law. A city cannot use a legalization application as a revenue opportunity beyond what the safety fix genuinely requires.

What this does not do

AB 2533 is a floor, not a blanket amnesty. Some limits worth naming plainly, based on the statute as written:

• It only covers units built before January 1, 2020. A garage converted in 2021 without a permit does not get this protection.
• It does not waive the building code itself. The unit still has to meet the safety standard in section 17920.3; the law changes what a city can use to refuse the permit, not what the finished unit has to look like.
• It does not touch zoning, setback, or lot coverage rules independently. Those are governed by the state's separate ADU statutes (Government Code sections 66310 to 66342), not by this bill specifically.
• It does not exempt the owner from state or local fire, health, or accessibility standards that a city can lawfully require to make the space safe to occupy.

The practical sequence for an owner

1. Confirm the build date. If the ADU or garage conversion was built on or after January 1, 2020, this statute does not apply to it; talk to your city about its standard ADU permitting process instead.
2. Consider a private inspection first. The law entitles you to get a confidential third party code inspection from a licensed contractor before you ever file with the city. Use it to see the real scope of what needs fixing.
3. Request the city's section 17920.3 checklist. Agencies are required to make this public. It tells you exactly what standard your unit is being measured against.
4. Apply for the permit. The city can require corrections tied to genuine substandard conditions, but it cannot deny the permit outright for lesser violations, and it cannot penalize you for the original unpermitted work.
5. Budget for the fix, not for city fees. Impact and connection fees are off the table except where new utility infrastructure is genuinely required. Your cost driver is the physical correction work, not a city surcharge.

Why this matters for South Bay owners specifically

El Segundo, Manhattan Beach, Hermosa Beach, Redondo Beach, Torrance, Hawthorne, Inglewood, Gardena, and Carson all sit in older housing stock with a long history of garage conversions and informal in law units, many predating any ADU ordinance at all. AB 2533 is a state floor that every one of those cities has to honor, but each city can still run its own application process, checklist format, and inspection scheduling. Confirm the local procedure with your city's building and safety division before you file, since the statute sets the ceiling on what a city can deny, not the paperwork it will ask you to complete.

FAQ

Does AB 2533 apply to a garage conversion built in 2022?

No. The legalization protection in the statute applies only to unpermitted ADUs and junior ADUs constructed before January 1, 2020. A newer unpermitted conversion falls under the standard ADU permitting rules instead.

Can a city still deny my legalization permit?

Yes, but only for conditions that make the building substandard under Health and Safety Code section 17920.3, things like structural or life safety hazards. It cannot deny the permit for lesser code nonconformities.

Will legalizing my unit trigger new impact fees?

The law bars impact fees and connection or capacity charges for legalization, except where new utility infrastructure is actually required to meet the section 17920.3 standard.

Do I have to let the city inspect before I apply?

No. You are entitled to get a confidential third party inspection from a licensed contractor first, so you can assess the scope privately before deciding whether and how to apply.

Does this law change zoning rules like setbacks or unit size for my ADU?

No. AB 2533 addresses building standard violations and the permit denial process. Zoning and dimensional standards are governed separately under the state's broader ADU statutes and local ordinances.

This article is general information about a specific California statute, not legal advice, and code enforcement outcomes depend on the condition of your specific structure. Confirm your city's legalization procedure and get a licensed contractor's assessment before filing any permit application.

Topics: compliance, ADU, unpermitted construction, AB 2533, South Bay, landlord compliance

Get a free management quote

Back to the Schofield Properties blog

Schofield Properties is a family run property management company at 323 Richmond St, El Segundo, CA 90245. We have managed the South Bay since 1972 and personally oversee about 186 doors today. Book a call to talk about your property.