CA AB306

Imposes a six-year moratorium (October 1, 2025 to June 1, 2031) prohibiting cities, counties, and state agencies from adopting new or modified building standards affecting residential units, with exceptions for emergency health and safety standards, home hardening/wildfire protection, and certain administrative improvements

Allows local jurisdictions to maintain building standard modifications that were in effect as of September 30, 2025, and permits changes aligned with general plans approved by June 10, 2025 that allow mixed-fuel residential construction while incentivizing all-electric construction

Requires the California Building Standards Commission to reject local building code modifications for residential units during the moratorium period unless they meet specified exceptions, with a 45-day review timeline for administrative practice changes

Establishes that building standards in effect when a model home design permit is approved will apply to all future homes built from that same design in the same jurisdiction for up to 10 years

Adds the International Wildland-Urban Interface Code to the definition of "model code" for California building standards and limits intervening period code changes to editorial corrections, emergencies, and State Fire Marshal wildfire amendments