Third-party agencies (PDF) are certified by the Department of Housing and Community Development's (HCD's) Manufactured Housing Program staff to perform as a Design Approval Agency (DAA) and/or a Quality Assurance Agency (QAA), enforcing design and construction approval of commercial modulars (CMs), special purpose commercial modulars (SPCMs), and multifamily manufactured homes (MFMHs) designated for sale in California.

Third-party agencies, once approved, provide these services as a small business acting on behalf of HCD.