Governor Newsom signs four new accessory dwelling unit bills

Governor Gavin Newsom signed four new bills into law last month that modify California's accessory dwelling unit regulations, continuing the state's annual tradition of refining ADU and junior ADU policies.

The legislation includes AB 462, AB 1154, SB 9, and SB 543, with AB 462 taking immediate effect as an urgency measure while the remaining three bills become active January 1, 2026.

The changes are primarily technical and clarifying in nature, building on previous ADU reforms that established 60-day ministerial approval requirements, allowed separate sales of ADUs from primary dwellings in certain cases, and enabled property owners to legalize unpermitted units.

AB 462 specifically addresses coastal development permits for ADUs in disaster-affected areas, modifying longstanding requirements that ADUs in coastal zones obtain additional permits beyond standard local approvals.

Previously, these coastal development permits were not subject to the state's 60-day approval timeline and could be appealed to the California Coastal Commission.

Local jurisdictions must update their ordinances promptly to comply with the new state requirements, as non-conforming local laws risk being declared null and void entirely.

For California homeowners and developers, these ongoing legislative adjustments continue to expand opportunities for adding secondary housing units to existing properties, though specific impacts will depend on individual project locations and local implementation of the updated regulations.