Accessory dwelling units: ministerial approval: single-family dwellings.

Assembly Member Quirk-Silva's proposal to expand accessory dwelling unit (ADU) development would require local agencies to ministerially approve two detached ADUs on lots with single-family homes, doubling the current one-unit maximum. The measure maintains existing four-foot side and rear setback requirements while capping total floor area at 800 square feet per unit.

The legislation outlines specific parameters for ADU approval and construction. Local agencies must process applications ministerially when units meet prescribed standards for exterior access, fire safety setbacks, and height limitations. The bill prohibits requiring fire sprinklers in ADUs unless mandated for the primary residence and bars agencies from imposing additional objective development standards beyond those explicitly authorized.

For multifamily properties, the measure preserves current provisions allowing ADUs within unused spaces like storage rooms and basements, provided units comply with building codes. Local agencies must permit at least one ADU within existing multifamily dwellings and allow ADUs in up to 25% of existing units. The bill requires ADU rentals to exceed 30-day terms and allows agencies to mandate recent percolation tests for units connecting to onsite wastewater systems.