At the heart of any code enforcement program is an adopted fire code and related standards. Codes and standards establish minimum requirements but should not prevent or discourage someone from exceeding the minimum requirement.
In the Woodside Fire Protection District, our Local Ordinances set the rules for fire safety. The Woodside Fire Protection District has adopted local fire ordinances—such as Fuel Mitigation Ordinance No. 24-01—that are tailored to our community’s wildfire risk. Because wildfire danger is especially high in our area, we have adopted stronger rules to better protect lives, homes, and open spaces.
These local ordinances are designed for our community’s safety. Think of state law as the baseline. Local ordinances add stronger protections to keep our community safer. Here, our ordinances are the governing rules everyone must follow. These ordinances were adopted by the District Board of Directors and are fully enforceable. They are the official fire safety standards for all properties within the Woodside Fire Protection District.
AB-2533: What Homeowners Need to Know | Fire Department Guide
Fire Department Public Guide
Understanding AB-2533
for Homeowners
California's law that helps homeowners legalize unpermitted ADUs — and what it means for fire safety.
Signed: September 28, 2024
Applies to: ADUs built before Jan 1, 2020
Source: Gov. Code §66332
📋
What Is AB-2533?
Many California homeowners have unpermitted ADUs (Accessory Dwelling Units) — extra living spaces like converted garages, backyard cottages, basement apartments, or in-law units that were built without going through the official permit process.
Before this law, homeowners in that situation risked serious consequences if the unit was discovered — including large fines and demolition orders. AB-2533 changes that by giving homeowners a clear, protected pathway to get their unpermitted unit properly permitted.
💡
The simple version: If your unpermitted ADU or JADU was built before January 1, 2020, this law says your local agency must work with you to get it permitted — and cannot fine you just for coming forward to apply.
ADU — Accessory Dwelling Unit
A separate living space on your property with its own kitchen, bathroom, and sleeping area. Can be attached to your home or a completely separate structure.
JADU — Junior ADU
A smaller unit (500 sq ft or less) located inside your existing home — like a converted bedroom or interior suite. May share a bathroom with the main house.
Source: OSFM IB-25-004; Gov. Code §66313
✅
Does My Situation Qualify?
To use AB-2533's protections, your unpermitted ADU or JADU needs to meet a few basic criteria:
Your unit likely qualifies if:
It was built or converted before January 1, 2020
It's on a residentially zoned property (single-family or multi-family)
It doesn't already have a final court-ordered demolition order against it
You are willing to make any corrections needed to meet health and safety standards
AB-2533 does NOT apply if:
The unit was built on or after January 1, 2020 — standard permitting rules apply
The building has been officially declared substandard under Health & Safety Code §17920.3
The unit is on a commercially zoned property
⚠️
Important: This law does not give you a pass on fire and life safety issues. If your unit has conditions that are dangerous — like missing smoke detectors, no safe way to escape in a fire, or major structural hazards — those must be corrected. The law was designed to help you fix those things, not avoid them.
Source: AB-2533, Gov. Code §66332(a)-(c)
🔑
How the Process Works
Here is a plain-language overview of how the legalization process works under AB-2533:
Get informed before you apply
Your local agency is required by law to publish a checklist of what would make a unit "substandard" and must let you know you can hire a licensed contractor for a confidential code inspection before submitting any paperwork — meaning what the contractor finds stays between you and them.
Submit your permit application
Once you apply to permit your unpermitted ADU or JADU, the law immediately protects you. The local agency cannot penalize you or fine you just because the unit was previously unpermitted.
Inspection and recommendations
A local agency inspector may visit to check the unit against health and safety standards and give you a list of what needs to be corrected. This is to help you get into compliance, not to punish you.
Make required corrections
The local agency must approve the permits needed to correct any issues. You'll address things like safety systems, electrical, plumbing, or structural concerns as required.
Final approval
Once corrections are complete and pass inspection, your ADU or JADU is officially permitted. You now have a legal unit with proper documentation.
💬
On fees: You generally cannot be charged impact fees or connection/capacity fees during this process — unless new utility infrastructure is actually needed to meet health and safety standards.
Source: AB-2533, Gov. Code §66332(d)-(f)
🔥
What Fire Safety Requirements Apply?
AB-2533 does not create or change fire code requirements — those come from the California Fire Code and California Building Code. What the law does is set Health & Safety Code §17920.3 as the standard: if your unit has any of these conditions, they must be corrected as part of the permitting process.
🚨
Fire departments can enforce life-safety violations at any time — regardless of where you are in the AB-2533 process. Getting your application in does not pause fire code enforcement.
Common fire and life safety conditions that must be addressed:
🚪 Emergency Exits (Egress)
Every bedroom must have a window or door that can be used to escape in a fire. If yours are too small, blocked, or missing, that must be corrected.
🔔 Smoke & CO Detectors
You need working smoke detectors in and outside every bedroom, and carbon monoxide detectors if you have gas appliances or an attached garage. Battery-only detectors don't meet code — they must be hardwired.
🧱 Fire Separation Walls
If your ADU shares a wall with your main home or is very close to a property line, that wall needs to be fire-rated — meaning it can slow a fire from spreading for a specific period of time.
🌿 Wildfire Zone Requirements
If your property is in a High or Very High Fire Hazard Severity Zone, additional standards apply — including fire-resistant exterior materials and ember-resistant vents. These apply to all structures, including ADUs.
💡
One window, two jobs: A bedroom window can serve double duty — as an emergency escape (egress) and as the room's natural light and ventilation requirement — as long as it's the right size. However, if that wall also needs to be fire-rated (because it's close to a property line or shared with the main house), those two requirements conflict. In that case, the egress window would need to be on a different wall.
Source: H&S Code §17920.3; OSFM IB-25-004; CA Fire Code; CA Building Code
💧
Do I Need Fire Sprinklers?
The State Fire Marshal has issued clear guidance on this. The rules depend on whether your main house already has sprinklers — not just the ADU.
Sprinkler Requirement Quick Reference — Per OSFM IB-25-004
Your main house already has a fire sprinkler system
→
Sprinklers required in your ADU
Your main house does not have sprinklers
→
Sprinklers NOT required in your ADU
You're adding an ADU to a brand new home being built
→
Sprinklers required — new construction requires them
Your ADU triggers the question: does the main house now need sprinklers?
→
No — adding an ADU cannot force you to retrofit sprinklers in your existing home
⚠️
Check your local rules: Some cities and counties have adopted additional requirements beyond state law — for example, some require sprinklers in ADUs located in High Fire Hazard Severity Zones even if the main house doesn't have them. Always confirm with your local fire department or building department.
No. AB-2533 specifically prohibits the local agency from penalizing you for having an unpermitted ADU once you submit a permit application. The whole point of the law is to encourage homeowners to come forward without fear of punishment.
Unfortunately, no. AB-2533 only covers ADUs and JADUs built before January 1, 2020. If yours was built after that date, you would need to go through the standard permit process, which does not include the same penalty protections. Contact your local building department for guidance.
Under Health & Safety Code §17920.3, a building is "substandard" when specific dangerous conditions exist — things like hazardous wiring, structural failure, no way to safely exit, or serious fire hazards. AB-2533 says the local agency can only deny your permit if your unit meets this definition. If the issues are less serious, they must work with you to fix them rather than deny or demolish. The local agency is required to publish a checklist of exactly what qualifies as substandard so you can check before you apply.
Yes — and the law specifically protects this right. You can hire a licensed contractor to inspect your unit and tell you what would need to be corrected before you submit anything to the government. That inspection is confidential. It is a smart way to go in prepared and avoid surprises.
The law limits what fees can be charged. You generally cannot be required to pay impact fees or utility connection/capacity fees — unless the work genuinely requires new utility infrastructure to meet safety standards. Standard permit fees may still apply; check with your local agency for specifics.
Being in a Fire Hazard Severity Zone does not prevent you from using AB-2533 to legalize your ADU. However, the State Fire Marshal has made clear that additional building standards may apply — including requirements from the California Fire Code and California Building Code Chapter 7A for ignition-resistant construction. Your local fire department or AHJ (Authority Having Jurisdiction) can tell you what additional standards apply to your property.
Not necessarily. As long as there is not already a final court order for demolition, you may still be able to apply under AB-2533. We strongly recommend contacting your local building department and, if needed, consulting a licensed contractor or attorney to understand your specific situation and options.
Have Questions?
Contact your local fire department or building department for guidance specific to your property.
Sources: AB-2533 (Gov. Code §66332, Chapter 834, Statutes of 2024) · H&S Code §17920.3 · OSFM Information Bulletin IB-25-004 (March 3, 2025) · osfm.fire.ca.gov · leginfo.legislature.ca.gov
This page is for general informational purposes only and does not constitute legal advice. Requirements vary by jurisdiction.
