Factory-Built Housing

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, form HCD FBH 314 (PDF) 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.

Insignia of Approval

Insignia Requirements:  All factory-built housing (FBH) and building component systems that are offered for sale within the state to first users (meaning a person, firm, or corporation which initially installs factory-built housing or component) must bear an Insignia of Approval issued by HCD (California Health and Safety Code, Section 19980 ).  The insignia must be on the FBH unit or building component before it is shipped.  After the unit is installed, the insignia can be removed.



The insignia informs local building officials that the unit has been inspected and approved in accordance with the approved plans, which must be submitted to the local agency.  Installation of factory-built housing or building components is subject to inspection by the local building department.  


Alterations to factory-built housing after manufacture, but prior to installation, must receive approval from HCD's Division of Codes and Standards. After installation, alterations made to factory-built housing must receive approval from the local building department.  


Check the listing of fees (PDF) associated with factory-built housing with notations indicating when a fee applies.

Frequently Asked Questions (FAQs)

The Factory-Built Housing Pamphlet (PDF) has additional information about the program in FAQ format.

Forms and Publications

  • HCD FBH 307 (PDF) — Design Approval Agency and/or Quality Assurance Agency Certification Application
  • HCD MH/FBH 443 (PDF) — Notice of Third-Party Contract or Contract Termination
  • HCD FBH 314 (PDF) — Factory-Built Housing Handbook for Local Enforcement Agencies, Builders, and the General Public
  • HCD FBH 315 (PDF) — Factory-Built Housing Pamphlet (Frequently Asked Questions)

Laws and Regulations

The Laws and Regulations page provides more information about the applicable laws and regulations governing the Factory-Built Housing Program.

Third-Party Design Approval Agencies

Third-party agencies (PDF) perform as Design Approval Agencies (DAAs) and/or Quality Assurance Agencies (QAAs) acting on behalf of HCD. For more information, visit the Third-Party Design Approval Agencies page.

Submit a Complaint

HCD receives and processes complaints related to factory-built housing construction defects. Owners may request assistance where there is believed to be a failure to meet the required building and design requirements for factory-built housing systems or components. HCD conducts complaint investigations for alleged violations related to factory-built housing construction defects. If you would like to file a factory-built housing construction defect complaint, visit HCD’s Submit a Complaint page.