Installer Requirements

Any individual or company that is paid to install a manufactured or mobile home must be certified to perform the installation (RCW 43.22A).  This includes dealers, manufactured or mobile home park owners, and contractors. Homeowners who are working on their own residence are exempt from these requirements, as long as they do not pay anyone for installation work.

Verify your installer - Ask to see their certified manufactured home installer card or certificate with their certification number and verify the expiration date.  Or you can verify your certified installer using our online tool.

Supervision & installer certification tag requirements

A certified manufactured home installer must be on site at all times during each phase of installation. Different installers can supervise each phase of installation. Licensed plumbers or electricians working within the scope of their license do not need additional supervision or certification.

Certified manufactured home installers must place a red metallic installer certification tag, issued by L&I, on each home they install before it is inspected by the local jurisdiction. This tag must list all installation work performed by the installer. One tag is required for each installer.  For example, if one installer sets the forms and pours the concrete runners and another installer performs all other installation work, there should be two tags affixed to the home. These tags should be placed directly above or below the HUD certification label, or temporarily located in plain sight within 3 feet of the home's front entry. Tags can only be removed by the homeowner after the local enforcement agency has issued its final approval.

Work that requires a certified installer

  • Construction of the foundation system, including building forms for concrete
  • Setup and assembly
  • Installing support piers
  • Installing earthquake-resistant bracing systems
  • Connection to the foundation system and support piers
  • Re-leveling of the home
  • Installing skirting of any kind, whether decorative or load-bearing
  • Connections to the on-site water and sewer systems for normal operation of the home
  • Installing ground anchors
  • Other service work to the home that falls under the definition of mobile or manufactured home installation (See RCW 43.22A.010 and WAC 296-150I-0020 for definitions)

Work that does not require a certified installer

  • Site preparation, such as grading and excavation
  • Sewer and water connections outside of the building site
  • Pouring concrete into forms
  • Painting and drywall finishing
  • Carpet installation
  • Specialty trades responsible for constructing accessory structures such as garages, carports and decks
  • Specialty work performed by a licensed plumber or electrician that falls within the scope of their license

Forms for Installers

  • Installer certification tags shall be removed only by the homeowner following final approval of the installation of the home by the local enforcement agency.


For more information:

RCW 43.22 Sections 335-495 - Manufactured/mobile homes, factory-assembled structures. (
RCW 43.22A - Mobile and Manufactured Home Installation. (
WAC 296-150I - Manufactured Home Installer Training and Certification Program, Installation Code. (
WAC 296-150M - WA Manufactured Home Code. (

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