Marin County describes an AB 2533 legalization program for unpermitted accessory dwelling units (ADUs) and junior ADUs (JADUs) built before January 1, 2020. The County reviews the plans and health-and-safety conditions, and its final letter has a narrower scope than an occupancy certificate. The County’s steps apply within its jurisdiction; incorporated cities may have their own procedures.
Review the inspection checklist before applying
The County recommends reviewing its inspection checklist to understand what Building & Safety will examine. Before providing a name or address, an owner may complete an optional confidential third-party code inspection by a licensed contractor to learn about the unit’s condition or potential improvements. This private inspection is preparatory only; it does not establish the County’s findings or replace the County’s inspection.
To apply, the County asks for plans prepared by a licensed design professional, an application and acknowledgement, and drawings identifying the address and parcel number. The listed drawings include a site plan showing boundaries, setbacks, structures and flood zones; a floor plan labeling rooms and dimensions; and elevations showing height, grade and fences. Environmental Health Services, Fire and Land Development also review the project as part of the County’s health-and-safety process. Additional flood-area conditions may apply.
Track the one-year deadline and final record
After the permit application is filed, the County says the owner has one year to complete the legalization process. If the process is not completed within that period, the application information may be sent to Code Enforcement for corrective action. Once the permit issues, the owner must arrange inspection, correct health or safety violations and obtain any additional permits needed for the corrections.
After a passing inspection, Marin County issues a Letter of Legalization, which the County expressly distinguishes from a Certificate of Occupancy. Do not treat the letter as proof of a separate occupancy approval or of work outside the reviewed scope. Check the County’s current ADU Legalization Program page for its forms, checklist and current requirements. For a particular property, confirm eligibility, active enforcement cases, permits, health reviews, inspection results and the scope of the final letter with the County.