California has hundreds of thousands of unpermitted ADUs: garage conversions, back houses, and basement units built without permits. AB 2533 (Carrillo, 2024) expanded the state's amnesty rule so that, for an ADU or JADU built before January 1, 2020, a city cannot deny a permit to legalize it unless the unit is substandard under the health and safety code.
What the city has to do
- Review the unit against health and safety standards only, not current zoning or building code for new construction.
- Post a checklist of what qualifies as substandard, so the standard is objective.
- Allow a licensed contractor, architect, or engineer to inspect and certify the unit if the owner prefers that route.
- Waive impact fees, connection fees, and capacity charges for the legalization permit.
What this means in practice
A 1980s garage conversion with a kitchen and a bathroom that works, has egress, smoke and CO detectors, and no life-safety hazards can be permitted as an ADU without meeting today's setbacks, parking rules, or energy code. The owner gets a legal, insurable, financeable unit and the rent it already produces becomes bankable income on an appraisal.
The 2020 cutoff
The amnesty applies to units built before January 1, 2020. Units built after that date still have to meet the ADU standards that applied when they were built, though the state's broader ADU rules are generous enough that most still qualify under a normal application.
Why legalize now
Unpermitted units cannot be counted on an appraisal, cannot be disclosed cleanly on sale, and expose the owner to code enforcement and uninsured liability. Legalized under AB 2533, the same unit adds value under the income or comps approach and can be part of a larger project: an SB 1211 or two-ADU plan that stacks new units on top of the legalized one.
Parcy flags existing accessory structures on your parcel from building footprint data. If you have an unpermitted unit, tell us in a consult and we will map the amnesty path with the new units.
Frequently asked questions
Can a city deny a permit for my unpermitted ADU?
For an ADU built before January 1, 2020, only if the unit is substandard under the health and safety code. Zoning and current building code for new construction do not apply.
Do I pay impact fees to legalize an ADU?
No. Impact fees, connection fees, and capacity charges are waived for the legalization permit under AB 2533.
Informational only. Not legal, architectural, or investment advice. Confirm current rules with your local planning department.