Accessory dwelling units and junior accessory dwelling units.

Senator McNerney's accessory dwelling unit legislation revises California's regulatory framework for both accessory dwelling units (ADUs) and junior accessory dwelling units (JADUs), establishing new standards for size requirements and approval processes. The bill redefines JADUs as units with no more than 500 square feet of interior livable space while maintaining the requirement that they be contained within single-family structures.

The legislation implements strict timelines for local agencies' permit processing, requiring determinations of application completeness within 15 business days and final decisions within 60 days of receiving completed applications. Local agencies must provide detailed written explanations for incomplete or denied applications, along with specific remediation instructions. The bill creates an appeals process for denied applications, mandating final determinations within 60 business days of receipt.

The measure adjusts fee structures by prohibiting impact fees on ADUs with 750 square feet or less of interior livable space and JADUs with 500 square feet or less. For larger ADUs, impact fees must be charged proportionally based on the primary dwelling's square footage. Local agencies must submit ADU and JADU ordinances to the Department of Housing and Community Development within 60 days of adoption for review. Ordinances that fail to meet state requirements or are not submitted within the specified timeframe become void, requiring agencies to apply state standards until compliant ordinances are adopted.