The purposes of the Factory-Built Housing (FBH) Program are to ensure the health and safety of persons using or purchasing factory-built homes or FBH building components, and to provide California residents with reduced housing costs through mass production techniques resulting from a factory production environment.

In order to achieve these responsibilities, the following activities are conducted by the Department of Housing and Community Development (HCD) pursuant to the Health and Safety Code, commencing with Section 19960.

• Plan check of FBH designs through HCD-approved Design Approval Agencies.
• In-plant inspections of FBH through HCD-approved Quality Assurance Agencies.
• Insignia of Approval issuance and record-keeping.
• Application review for eligibility to act as a Design Approval Agency and perform plan checking on behalf of HCD.
• Application review for eligibility to act as the Quality Assurance Agency or Quality Assurance Inspector and perform in-plant inspection on behalf of HCD.
• Monitoring of Design Approval and Quality Assurance Agencies, Quality Assurance Inspectors, and local building departments.
• Complaint handling and investigations.

HCD regulates the manufacturing of factory-built housing and building components manufactured for sale in California, which are defined as follows in state law:

• Factory-Built Housing is a residential building, dwelling unit, individual dwelling room, or combination of rooms, or building components, assembly, or system manufactured so that all concealed parts or processes of manufacturing cannot be inspected before installation.
• A Building Component is a subsystem, subassembly or other system designed for use in or as part of a structure which may include structural, electrical, mechanical, plumbing, and fire protection systems or any other system affecting health and safety.

The Factory-Built Housing Handbook for Local Enforcement Agencies, Builders, and the General Public (PDF), form HCD FBH 314 provides information to assist local building agencies and the public in their understanding of the manufacture, assembly, installation, post-installation alteration and code enforcement upon factory-built homes, their systems and their components.